CHAPTER 35

Achlya Nees von Esenbeck Nova Acta Phys.–Med. Acad. Caes. Leop.–Carol. Nat. Cur. 11:514. 1823

Hydronema Carus, Nova Acta Phys.–Med. Acad. Caes. Leop.–Carol. Nat. Cur. 11:514. 1823.

Monoecious or dioecious. Sporangia fusiform, naviculate, cylindrical, or clavate; renewed sympodially or by basipetalous development and cymose branching. Spores mono- or dimorphic; when the latter the two flagella are quickly evanescent; primary spores at discharge encysting and clustering at the exit orifice in a spherical, hollow mass that subsequently may fall away from the sporangium; cysts floating free and then germinating to produce laterally biflagellate, reniform planonts, or remaining in the spherical cluster and then releasing the secondary planonts; in some , the secondary sporangia discharge the spores in a dictyucoid or thraustothecoid manner, or the spores germinating in situ in an aplanoid fashion. Gemmae present or absent; functioning as sporangia, or oogonia, or producing new hyphae directly upon germination. Oogonia lateral on stalks or various lengths, or terminal, intercalary or sessile; variously shaped, but predominantly spherical or pyriform; sometimes reverting to the production of hyphae, or proliferating. Oogonial wall pitted or unpitted; smooth or ornamented on the outer surface, smooth or irregular on the inner. Oospores centric, subcentric, subeccentric, or eccentric; occasionally aborting; one to many in an oogonium; germinating by producing a mycelium directly or by a germ tube bearing a terminal sporangium. Antheridial branches present or absent, or reduced to a hypogynous cell; when present, diclinous, monoclinous, androgynous, or exigynous. Antheridial cells predominantly tubular or clavate; attached apically, laterally, or in a digitate fashion. Type species: prolifera Nees von Esenbeck, Nova Acta Phys.-Med. Acad. Caes. Leop.–Carol. Nat. Cur., 11:514. 1823.

The Achlya has a blemished early history. From the figures accompanying the description of Bysus aquatica in Florae Danicae (O. F. Müller, 1782:6, pl. 896) it seems likely that the genus was first known under this binomial. The illustrations of this “alga” do not show sporangia or oogonia, but the clavate ends depicted on some of the filaments recall one of the stouter Achlyas. In 1819, a representative of the genus was accorded yet another binomial, Vaucheria aquatica, this proposed by Lyngbye. It is not clear whether Agardh (1824) was aware of Nees von Esenbeck’s work, for he reduced Byssus aquatica, Vaucheria aquatica, Schrank’s (1798) Conferva piscium, and Carus’ Hydronema to synonymy with Leptomitus clavatus, but made no mention of Achlya. In 1949, Kützing included Hydronema as a synonym of ferax, but as the organism named by Carus was clearly an Achlya, it is obvious that Kützing’s concept of Saprolegnia also included Achlya.

473 Various proposals to divide the genus into subgenera or subgroups have appeared in the literature. An early attempt at such a division was that by Schröter (1893), in which two subgenera were recognized, Euachlya (for those species with smooth oogonia), and, for the ornamented Achlya spinosa, Acanthachlya. Coker (1923) separated the genus into four subgenera, Centroachlya (centric oospores), Euachlya (eccentric oospores), Glomeroachlya (branched oogonial stalks), and Thraustoachlya (spore release by some sporangia in a thraustothecoid manner). Centroachlya and Euachlya were further subdivided. Three subgenera, erected on the basis of oospore structure, ere proposed by Johnson (1956b). Two of these, Centroachlya and Subcentrica, certainly must be discarded since it is abundantly clear that centric and subcentric oospores can occur in the same species, and even in individual oogonia. Cejp (1959:127, 163, 176) reduced Coker’s and Johnson’s subgenera to synonymy with sectional designations – Prolifera, Apiculata, and Racemosa – that he created. Although he did not recognize subgenera, Dick (1973) carefully bundled the various species of the genus into groups based upon such characters as egg structure, racemose or glomerulate arrangement of oogonia, and the nature of oogonial wall ornamentations. The most extensive infrageneric segregation of the genus Achlya seems to be that adopted in 1954 by Naumov. He divided the genus into four subgenera, Proliferae, Hypogynae, Saprolegniopsis, and Thraustoachlya. The largest subgenus, Saprolegniopsis was further divided into two sections, Spinosae and Leiotheca, with the latter split into two subsections, Polyandrae and Brevipedes. Finally, Naumov segregated the subsection Brevipedes into the “divisions” De Baryanae and Racemosae. This detailed fracturing seems unnecessarily complicated. None of the infrageneric schemes of classification appears, in retrospect, to offer any proof of natural relationships. This being so, the retention (or introduction) of additional names provides only a convenience, and we see no reason to perpetuate a scheme which has no more value than this. Accordingly, we do not recognize subgeneric groupings. Members of the genus have been used extensively in physiological and biochemical studies (Chapters 16, 19, 20), and in ecological work (Chapters 4, 5). Perhaps the genus is best known for the work which has been done with its dioecious species on the hormonal control of sexual reproduction (Chapter 21). Some taxonomic implications have been extracted from analyses of DNA base composition (Green and Dick, 1972). A few species have been shown (Win-Tin and Dick, 1975) to have gametangial meiosis. The of the genus is difficult; representatives of the genus do not always fall into place readily. This has, of course, been recognized for some time, and was first pointed out – with specifics – by Moreau and Moreau (1935a). Members of the genus producing smooth oogonia with eccentric oospores have long been notoriously difficult, and their identification often doubtful. Evidence from an analysis of several hundred collections of these Achlyas has prompted a severe revision of this section of the genus, much as Seymour (1970) did for the ferax complex of Saprolegnia.

474 Ordinarily, recognizing Achlyas in baited cultures or on organic substrates is done with ease, but there are exceptions that are sure to be encountered. A few species – A. dubia, for instance – practice thraustothecoid and dictyucoid spore discharge particularly from the secondarily produced sporangia. It is essential, therefore, that young cultures be examined so that the nature of discharge of the first-formed sporangia can be determined. Assignment of individuals to the genus is on the basis of these primary sporangia. By the inclusion into Achlya of two species formerly assigned to de Bary’s (1888) Aplanes, we have admitted taxa that consistently produce sporangia in such small numbers and so rarely that the species effectively are seen only as asporangiate forms. The two species, A. treleaseana and A. androgyna, are recognized easily by their dolioform, intercalary oogonia (these often develop only after 4–7 days in gross cultures), and appear to be restricted to acid bog habitats. See also, remarks under Protoachlya and Brevilegnia.

Key to the species of Achlya

1. Thallus monoecious when isolated, although some cultures capable of cross-conjugating (interspecific mating) ...... 2 1. Thallus dioecious, being potentially antheridial or oogonial donors, when isolated; but some cultures capable of self-conjugation and expressing it on isolation ...... 43 2. Oospores centric, subcentric, or both ...... 3 2. Oospores eccentric ...... 17 3. Sporangia sparse or abundant, but present in initial growth period of isolates; special culture conditions not required to induce sporangia ...... 4 3. Sporangia extremely rare, and not present in initial growth period of isolates; may be induced only by special culture conditions ...... 16 4. Oogonial wall densely ornamented ...... 5 4. Oogonial wall predominantly smooth, but some oogonia may be very sparsely ornamented ...... 9 5. Oogonial wall ornamentations mammiform or predominantly so ...... A. radiosa (p. 481) 5. Oogonial wall ornamentations not mammiform or only very rarely and inconspicuously so ...... 6 6. Antheridial branches lacking ...... A. stellata (p. 484) 6. Antheridial branches present, though sometimes sparse ...... 7 7. Oogonial wall ornamentations papillate ...... 8 7. Oogonial wall ornamentations predominantly stout, lobed, truncate, indented, broadly bifurcate,

475 or wart-like; occasionally long-conical or long-cylindrical ...... A. spinosa (p. 484) 8. Oogonia positioned in a racemose fashion on short stalks producing closely attending androgynous antheridial branches ...... A. colorata (p. 486) 8. Oogonia positioned at irregular intervals on short or long stalks that are often coiled or twisted; antheridial branches monoclinous or androgynous ...... A. papillosa (p. 489) 9. Antheridial branches strictly diclinous, and often deliquescing ...... 10 9. Antheridial branches some combination of monoclinous, androgynous, and diclinous, but never strictly the latter; seldom if ever, deliquescing ...... 11 10. Oospores small, predominantly 22–28 µm in diameter ...... A. oblongata var. oblongata (p. 490) 10. Oospores large, predominantly 36–49 µm in diameter ...... A. oblongata var. gigantica (p. 493) 11. Oospores centric ...... A. oligacantha (p. 494) 11. Oospores subcentric, or both subcentric and centric ...... 12 12. Oospores subcentric ...... 13 12. Oospores both centric and subcentric ...... 15 13. Oospores large, predominantly 44–52 µm in diameter ...... A. megasperma (p. 496) 13. Oospores small, predominant size less than 30 µm in diameter ...... 14 14. Antheridial branches predominantly diclinous; generally no more than 3 oospores per oogonium ...... A. bonariensis (p. 497) 14. Antheridial branches predominantly androgynous; generally 8 or more oospores per oogonium ...... A. polyandra (p. 498) 15. Oogonia generally positioned in a racemose fashion on the principal hyphae; not apiculate; antheridial branches predominantly androgynous ...... A. racemosa (p. 500) 15. Oogonia not racemosely arranged; frequently or occasionally apiculate; antheridial branches predominantly monoclinous ...... A. apiculata (p. 504) 16. Oogonia predominantly terminal or intercalary; usually dolioform, fusiform, or naviculate; wall pitted, smooth or sparsely to densely papillate; almost always with more than one oospore ...... A. androgyna (p. 507) 16. Oogonia predominantly lateral; usually

476 spherical or subspherical; wall unpitted, densely covered with truncate or rounded, conical projections or papillae, and additionally with some cylindrical, straight or hamate, lobed or inconspicuously dented ornamentations; oogonia not predominantly papillate only ...... A. ornata (p. 512) 17. Primary sporangia discharging in a thraustothecoid or achlyoid fashion; secondary ones predominantly in an achlyoid manner ...... A. dubia (p. 513) 17. Primary sporangia discharging only in an achlyoid fashion; secondary ones releasing spores in an achlyoid, dictyucoid, aplanoid, or thraustothecoid manner ...... 18 18. Large, inflated, subspherical to asymmetrical, thin-walled, unpitted; nonfunctional hyphal swellings intermingled among the oogonia ...... A. diffusa (p. 516) 18. Lateral, inflated, nonfunctional hyphal swellings lacking ...... 19 19. Oogonia generally lobed, hemispherical, or cylindrical ...... A. intricata (p. 517) 19. Oogonia generally spherical or obpyriform; sometimes angular or subspherical, but not distinctly lobed or hemispherical ...... 20 20. Oogonia large and inflated, predominant diameter greater than 100 µm ...... A. inflata (p. 518) 20. Oogonia not inflated, the predominant diameter less than 100 µm ...... 21 21. Oogonial wall predominantly smooth; some oogonia occasionally to rarely provided with one to a few wall projections or having wall substances protruding through some pits, but are neither sparsely nor densely ornamented ...... 22 21. Oogonial wall crenulate to sparsely or densely ornamented, occasionally to rarely smooth, but predominantly ornamented ...... 34 22. Antheridial branches seldom or rarely formed, or very sparse but persisting ...... 23 22. Antheridial branches usually present or frequently formed; persisting or deliquescing after attaching to an oogonium ...... 24 23. Oospores small, predominantly 15-18 µm in diameter, almost always single in an oogonium; antheridial branches rarely produced ...... A. oviparvula (p. 519) 23. Oospores predominantly 20-24 µm in diameter; predominantly 2-4 per oogonium; antheridial

477 branches sparse ...... A. caroliniana (p. 520) 24. Oogonia never containing more than one oospore ...... A. pseudoachlyoides (p. 522) 24. Oogonia may contain only one oospore, but some always with more than one ...... 25 25. Oogonial stalks usually long relative to the oogonial diameter, and generally bent or recurved ...... A. orion (p. 523) 25. Oogonial stalks usually short relative to the oogonial diameter; curved, sinuous, irregular, or straight, but rarely if ever bent or recurved ...... 26 26. Secondary sporangia frequently discharging spores in a thraustothecoid manner, but some also released in an achlyoid fashion ...... A. irregularis (p. 525) 26. Secondary sporangia not discharging spores in a thraustothecoid manner but may do so in a dictyucoid and aplanoid fashion in addition to achlyoid release ...... 27 27. Antheridial branches predominantly or nearly exclusively monoclinous or androgynous; when monoclinous, generally of near origin ...... 28 27. Antheridial branches predominantly or nearly exclusively diclinous, or usually diclinous and monoclinous in various proportions, but monoclinous ones often of distant origin ...... 30 28. Oospheres often not maturing, or oospores occasionally aborting; oogonial wall smooth; oogonial stalks generally longer than the diameter of the oogonium ...... A. debaryana (p. 527) 28. Oospheres usually maturing, and oospores seldom or rarely aborting; oogonial wall smooth or with sparse projections; oogonial stalks usually as long as the diameter of the oogonium, or shorter ...... 29 29. Oogonial wall occasionally provided with one to a few cylindrical or conical projections, or wall substances sometimes protruding through pits to give oogonium a sparsely or faintly papillate aspect; oospores predominantly 3-6 per oogonium ...... A. cambrica (p. 535) 29. Oogonial wall smooth; oospores predominantly 6-14 per oogonium ...... A. americana (p. 537) 30. Oogonium predominantly with one oospore ...... A. rodrigueziana (p. 540) 30. Oogonium predominantly with more than

478 one oospore ...... 31 31. Some oogonia provided with one to a few scattered, cylindrical or conical projections, or having wall substances protruding through some pits to give oogonium a sparsely and faintly papillate aspect; predominant number of oospores 3-6 per oogonium ...... A cambrica (p. 535) 31. Oogonia smooth; predominant number of oospores in range of 6-16 per oogonium ...... 32 32. Antheridial branches strictly diclinous; oospheres predominantly maturing; antheridial branches often deliquescing after contacting oogonia ...... A. prolifera (p. 541) 32. Antheridial branches predominantly but not exclusively diclinous; monoclinous ones often of distant origin; usually not deliquescing after contacting oogonia ...... 33 33. Antheridial branches occasionally coiling profusely about vegetative hyphae which may or may not bear oogonia, and also coiling around oogonial stalks ...... A. proliferoides (p. 545) 33. Antheridial branches not coiling about vegetative hyphae or oogonial stalks ...... A. debaryana (p. 527) 34. Oogonia never containing more than one oospore ...... A. achlyoides (p. 547) 34. Oogonia may contain only one oospore predominantly, but some always with more than one ...... 35 35. Antheridial branches lacking or rare to sparse; most oogonia lacking antheridia ...... 36 35. Antheridial branches present, usually abundant ...... 40 36. Antheridial branches absent ...... A. abortiva (p. 548) 36. Antheridial branches rarely or sparsely produced, most oogonia lacking antheridia ...... 37 37. Oogonia predominantly ornamented; smooth ones rarely or seldom produced ...... 39 37. Oogonia often smooth, but isolates always having some sparsely and unevenly ornamented ones ...... 38 38. Wall substances occasionally protruding through pits to give oogonia a faint and sparsely papillate appearance; oospores predominantly 24-28 µm in diameter; antheridial branches generally monoclinous

479 and androgynous ...... A. cambrica (p. 535) 38. Wall substance not protruding through pits; oogonia usually with 1-4 oospores; oospores predominantly 20-24 µm in diameter; antheridial branches generally monoclinous and diclinous ...... A. caroliniana (p. 520) 39. At least some oogonia produced on glomerulate stalks; almost always one oospore per oogonium; oogonial wall generally papillate or tuberculate; oogonia predominantly 30-40 µm in diameter ...... A. glomerata (p. 549) 39. Glomerulate oogonial stalks absent; predominantly with 1-4 oospores per oogonium; oogonial wall generally crenulate; oogonia predominantly 40-60 µm in diameter ...... A. crenulata (p. 550) 40. Antheridial cells usually attached to the oogonial wall at short, sometimes inconspicuous, tuberculate projections that are truncate terminally ...... A. subterranea (p. 552) 40. Antheridial cells not attached to tuberculate projections from the oogonial wall ...... 41 41. Antheridial branches strictly diclinous; oogonial wall ornamentations usually bilobed, cordate, and with intermingled, broad, stout, short tubercles; apex of ornamentations not thin-walled; oospores predominantly 1-2 per oogonium ...... A. lobata (p. 553) 41. Antheridial branches androgynous or monoclinous, never or rarely diclinous; oogonial wall ornamentations usually or predominantly conic-truncate, the apex thin-walled; oospores predominantly 4-8 per oogonium ...... 42 42. Some secondary sporangia discharging spores in a thraustothecoid manner, others in an achlyoid fashion; oogonial wall provided with stout papillae, rounded or truncate at apex, or with some crenulate protrusions; oogonial stalks not recurved; antheridial branches monoclinous or androgynous ...... A. priomoachlya (p. 554) 42. Secondary sporangia not releasing spores in a thraustothecoid manner;

480 oogonial wall provided with stout, conic-truncate projections, but wall not papillate or crenulate; oogonial stalks frequently recurved; antheridial branches androgynous, rarely monoclinous ...... A. recurva (p. 556) 43. Thallus dioecious when isolated, and only some strains capable of self-conjugating, but then not producing androgynous or monoclinous antheridial branches; interthallic mating both antheridial branches and oogonia cross-induced ...... 44 43. Thallus dioecious or monoecious when isolated, but freely capable of self-conjugation with antheridial branches being monoclinous and androgynous as well as diclinous; in interspecific matings only antheridial branches are cross-induced ...... A. heterosexualis (p. 558) 44. Oospheres predominantly maturing; oospores generally 1-18 per oogonium and predominantly 18-24 µm in diameter; gemmae cylindrical in both mating strains ...... A. ambisexualis (p. 560) 44. Oospheres infrequently to rarely maturing; oospores generally 5-10 per oogonium and predominantly 22-26 µm in diameter; gemmae in oogonial thallus spherical to short-cylindrical, spherical to cylindrical in antheridial thallus ...... A. bisexualis (p. 561)

Achlya radiosa Maurizio Mitt. Deutsch. Fischerei-Vereins 7:57, figs. 18, 19. 1899 (Figure 61 G-M)

Achlya decorata Petersen, Bot. Tidsskr., 29: 383, fig. 3a, e. 1909. (Also in Ann. Mycol., 8: 522, fig. 3a, e. 1910.) Achlya asterophora Minden, Kryptogamenfl. Mark Brandenburg, 5:549, fig. 2c. 1912. Achlya turfosa Johannes, Archiv- Mikrobiol., 14: 599, fig. 2. 1950. Achlya pseudoradiosa Rogers and Beneke, Rickia, 1: 246, pl. 2. 1962. Achlya echinulata Beroqui, in, Beroqui de Martinez, Darwiniana, 15:12, text fig. 1A, B; pl. 1, figs. C-E. 1969.

Monoecious. Mycelium moderately to noticeably dense, or diffuse and extensive; hyphae slender, abundantly to sparingly branched. Sporangia fusiform to cylindrical; straight, curved, or irregular; renewed sympodially; 98-620 x 7-70 µm. Spores

481 monomorphic; discharge and behavior achlyoid; in some instances not formed, and sporangium discharging its amorphous protoplasm; primary spore cysts 8-13 µm in diameter. Gemmae lacking. Oogonia lateral, usually in a racemose arrangement, occasionally terminal or intercalary; spherical, subspherical, or broadly obpyriform; (23-) 42-59(-77) µm in diameter, including wall ornamentations. Oogonial wall unpitted; provided generally with mammiform ornamentations, occasionally and additionally with bifurcate ones, infrequently having simple papillae, rarely crenulate; size and density of ornamentations variable. Oogonial stalks (1/4-) l (-5) times the diameter of the oogonium in length; straight, curved, bent, sometimes irregular. Oospores subcentric; spherical, ellipsoidal, or oval; 1-3(-6) per oogonium, and sometimes filling it; (19-) 29-35 (-41) µm in diameter; germination not observed. Antheridial branches predominantly androgynous, infrequently (?) monoclinous and of distant origin, rarely diclinous; slender, irregular, curved, bent, or twisted; unbranched or once-branched; persisting. Antheridial cells simple; clavate; persisting; apically appressed; fertilization tubes present or absent, not persisting.

There should be no difficulty in recognizing this well-marked species (although the list of synonyms suggests otherwise). The oogonial wall ornamentations are predominantly mammiform (Fig. 61J) and even in the rare instances when oogonia are papillate, crenulate, or sparsely ornamented, or generally have long, prominent ornamentations, some projections are always of this distinctive shape (Fig. 61 H, I, L, M). Characteristics other than the nature of the oogonial wall projections ordinarily are not needed for the identification of Maurizio’s species. Oogonia of Achlya radiosa usually are accompanied by short, curved, androgynous antheridial branches (Fig. 61 G, J), just as in A. racemosa and A. colorata. The nature of the oogonial wall readily separates these three species. We have never seen monoclinous antheridial branches in the specimens we have examined; they were evidently present (to what degree is not known) in Beroqui de Martinez’s (loc. cit.) variant. The synonymy recorded by T. W. Johnson (1956b:43) need not be further justified but there are additional species to consider. Achlya pseudoradiosa clearly is a variant of A. radiosa, as T. W. Johnson et al. (1975) demonstrated. Beroqui’s Achlya echinulata digresses from A. radiosa primarily in two characteristics. The Argentinian specimen had somewhat larger oogonia than A. radiosa, and some antheridial filaments (chiefly the monoclinous ones) were longer and more branched than is ordinarily encountered in Maurizio’s species. These are but minor digressions of no taxonomic consequence when it is recognized that the oogonia of A. echinulata have mammiform ornamentations and contain a single oospore for the most part. The illustrations provided by Beroqui de Martinez leave no doubt that she had collected A. radiosa. It has been demonstrated by some rather unrefined experimental work by T. W. Johnson et al. (1975) that conditions of culture incubation influence the expression of some structural features of Achlya radiosa. For example, the density of wall

482 ornamentation on the oogonia of some isolates was influenced by temperature (and to some degree the source of water used in hempseed cultures): there were fewer wall projections on oogonia of colonies grown at 25 oC in pond water than at 18 oC. Colonies grown in soil extract had slightly larger oogonia than did controls (in charcoal-filtered, distilled water). Oogonia in one test isolate grown in sterile or nonsterile soil extract at 18o or at 25 oC were sparsely ornamented with large projections. While Johnson and his collaborators found that all isolates grew on semisolid media, they generally did not develop beyond forming oogonial initials. In some instances, where a high nitrogen to low carbon ratio was built into the medium, oospores developed, but only scantily. In sum, while culture conditions modified size, density, and to some extent shape of the oogonial wall ornamentations in forms of A. radiosa, the characteristic mammiform projections were not eliminated. Neither oospore size nor number was influenced by the varied conditions under which the specimens were grown. Gepp (1899) misidentified specimens of Achlya radiosa as A. spinosa. As a consequence of that error, he inferred that his specimens provided a link between deBary’s A. spinosa and A. stellata. The very characteristic wall ornamentations of A. radiosa do not support Gepp’s views. Tiesenhausen (1912) reported two forms of A. radiosa from Switzerland. Only one of those described is recognizable as this species. The only records of the collection of Achlya radiosa in the New World are those from South America and additionally a report of the species from the United States (see distributional records to follow). The species is common in bog and acid lake habitats in Norway and Sweden, particularly in shallow waters containing detritus of Sphagnum spp.

CONFIRMED RECORDS: -- BRITISH ISLES: Dick (1969b: pl. 1, figs. 5-7; site of collection not recorded); Forbes (1935a:230, pl. 8, fig. 2); Gepp (1899:200, pl. 400, figs. 12, 13). CZECHOSLOVAKIA: Cejp (1934:191, pl. 1, figs. 14, 15; pl. 3, figs. 1, 2; 1959a:164, figs. 50, 51). DENMARK: Petersen (loc. cit.). GERMANY: Johannes (loc. cit.); Richter (1937:246, fig. 7). ICELAND: T.W. Johnson et al. (1975:115, 117, figs. 1-17). SOUTH AMERICA: Beneke and Rogers (1962:187) first report of A. pseudoradiosa, as an undetermined species; 1970:57; Beroqui de Martinez (loc. cit.); Milanez (1969:43); A. L. Rogers and Beneke (loc. cit.); A. L. Rogers et al. (1970: 101). SWITZERLAND: Maurizio (loc. cit.); Tiesenhausen (1912:283 et sqq., figs. 10-13. UNITED STATES: R. L. Butler (1975): figs. 129-132). RECORDED COLLECTIONS: -- BRITISH ISLES: Apinis (1964); Cook and Forbes (1933); Cook and Morgan (1934); Dick (1962, 1963, 1966); Dick and Newby (1961); Forbes (1935b); Hunter (1975); O’Sullivan (1965); Perrott (1959, 1960); Pickering et al. (1979); R. E. Roberts (1963); Willoughby (1965, 1974); Willoughby and Collins (1966). DENMARK: A. Lund (1934, 1978); Obel (1910b). GERMANY: Bock (1956). ICELAND: Howard et al. (1970). JAPAN: Hoshina et al. (1958). NETHERLANDS: Beverwijk (1948). SPECIMENS EXAMINED: -- AUSTRALIA (2), RLS. ICELAND (5), NORWAY (8), SWEDEN (10); TWJ: UNITED STATES (3), RLS. Centraalbureau (1).

483 Achlya stellata de Bary Bot. Zeitung (Berlin) 46:648, pl. 10, figs. 10, 11. 1888 (Figure 65 A-G)

Monoecious. Mycelium diffuse, moderately extensive; hyphae slender, sometimes sinuous; sparingly branched. Sporangia sparse or moderately abundant; fusiform, naviculate, or cylindrical; usually slightly irregular; unbranched; wall not thickened in vicinity of exit pore; renewed sympodially; 118-782 x 18-62 µm. Spores monomorphic; discharge and behavior achlyoid, very rarely aplanoid; spore cluster not persisting at exit orifice; primary spore cysts 10-12 µm in diameter. Gemmae lacking. Oogonia terminal or lateral, occasionally to infrequently intercalary; spherical, subspherical, obpyriform, or ovoid, occasionally broadly dolioform to nearly cylindrical, often with a prominent neck; (20-) 45-65 (-138) µm in diameter, including wall ornamentations. Oogonial wall unpitted; densely ornamented with short or long papillae, or with long, conical, straight or curved projections, apical one occasionally 1 1 attenuated. Oogonial stalks ( /3-) 1-1 /2 (-3) times the diameter of the oogonium in length; slender, curved and usually irregular; unbranched. Oospores subcentric; subspherical, oval, broadly ellipsoidal, or irregular or slightly constricted; 1(-8) per oogonium, and usually filling it; (16-) 30-38 (-48) µm in diameter; germination not observed. Antheridial apparatus lacking.

Achlya stellata is discussed in relation to A. spinosa and A. ornata in the respective accounts of these species. The variety multispora of A. stellata described by J. N Rai and Misra (1977a, b) is A. W. Ziegler’s (1958a) A. mucronata, which we are assigning to Protoachlya because of its spore behavior pattern. Humphrey (1893) and Coker (1923) believed that Achlya stellata was synonymous with A. cornuta (see excluded taxa). Both A. Fischer (1892: 356) and Minden (1912: 552) provided descriptions of A. stellata though neither evidently saw specimens. Their compilations seem to characterize A. spinosa rather than A. stellata.

CONFIRMED RECORDS: -- BRITISH ISLES: Dick (1960b:480, pl. 12, figs. 4-6; text figs. 2, 4a-e, j). GERMANY: de Bary (loc. cit.). ICELAND: T. W. Johnson (1974b:13, figs. 134-138); T.W. Johnson et al. (1975:113, figs. 18-32). INDIA: G. C. Srivastava (1975a:139). LATVIA: Apinis (1929a:228, pl. 4, fig. 1). MIDDLE EUROPE: Migula (1903:71). USSR: Naumov (1954:70). RECORDED COLLECTIONS: -- BRITISH ISLES: Dick (1963, 1966); Dick and Newby (1961); Ramsbottom (1915a; as A. cornuta)(?). SPECIMENS EXAMINED: -- AUSTRALIA (1), RLS. ICELAND (1), TWJ.

Achlya spinosa de Bary Abh. Senckenberg Naturf. Ges. 12:278 et sqq., pl. 4, figs. 13-18. 1881 (Figure 65 H-P)

484 Monoecious. Mycelium extensive, dense; hyphae slender, moderately branched. Sporangia infrequent; cylindrical, long-clavate, or long-fusiform; slightly irregular and curved; some provided with one or more slender, lateral exit tubes in addition to the terminal exit pore; wall thickened in vicinity of exit orifice; renewed sympodially or in basipetalous succession; 166-1815 x 16-45 µm. Spores monomorphic; discharge and behavior achlyoid, occasionally dictyucoid or aplanoid; spore cluster not persisting at exit pore; primary spore cysts 8-12 µm in diameter. Gemmae abundant; cylindrical, long-obpyriform, short-clavate; often curved; terminal and intercalary, single and catenulate. Oogonia infrequent; terminal or intercalary, infrequently lateral; spherical, ovoid, or dolioform; (30-) 50-60 (-108) µm in diameter, including wall ornamentations. Oogonial wall unpitted; densely or sparsely provided with stout, lobed, wart-like, or conical papillae, infrequently also having long, curved or straight, cylindro-conic projections; apical ornamentation occasionally attenuated and straight or irregular; larger projections truncate, indented, or broadly bifurcate. Oogonial stalks short or long, irregular or twisted; unbranched, or with one or two short, lateral, cylindrical projections. Oospores subcentric; ovoid, ellipsoidal, or subspherical, and sometimes laterally compressed or slightly irregular; 1(-4) per oogonium, and usually nearly filling it; (l7-) 30-38 (-45) µm in diameter; germination not observed. Antheridial branches present, but usually sparse or infrequent; androgynous or monoclinous: short, irregular, slender; unbranched; persisting. Antheridial cells simple; clavate to short-cylindrical; persisting; laterally appressed; sometimes hypogynous but producing a short, lateral, bent branch the apex of which contacts the oogonium; fertilization tubes present or absent.

Achlya spinosa and A. stellata seem very closely allied structurally, and are therefore best treated in a single discussion. Both species were relegated to the category of taxa of doubtful affinities by T. W. Johnson (1956b), but Dick (1960b) collected and studied living specimens of the two and correctly considered them to be recognizable entities. We have examined, as had Dick (1960), de Bary’s specimens of the two species (British Museum, Natural History), and are satisfied that A. spinosa and A. stellata are reflected as quite different species in the de Bary collection (Figs. 65 F, G and 65 H-M). The cultured specimens we have examined of both taxa conform quite comfortably to the fungi de Bary described. Achlya spinosa and A. stellata have ornamented oogonia, generally produce a single, subcentric oospore in each, and have much the same sporangial configuration (contrary to Dick, 1960b). The differences between the two species, however, are conspicuous. In A. spinosa, the wall projections are stout, prominent, and often irregular (lobed, truncate, bifurcate -- Fig. 65 O, P), while those of A. stellata are more regularly papillate to conical (Fig. 65 A, D, E). The oogonia preserved in the de Bary specimens reflect this difference precisely (compare Fig. 65 H-M and F, G). In contrast to A. spinosa, A. stellata lacks both gemmae and antheridial branches. The type of oogonium wall ornamentations produced by Achlya stellata (papillate or conical, not lobed, truncate, or furcate) evidently is a reasonably stable configuration.

485 Two isolates of A. stellata were grown (T. W. Johnson et al., 1975) in several different culture conditions (various combinations of water source and temperature) and the nature of the ornamentations described. In colonies grown in soil extract at 18o and 25 oC, for example, the wall projections produced by the oogonia were sparse but very much enlarged (T. W. Johnson et al. 1975: figs. 23-32), yet retained the configuration associated with the species: elongate-papillate or conical, and broad or slender and nearly echinulate. None was lobed, bifurcate, or irregular as is characteristic of A. spinosa. Modifications in the culture environment changed oogonial size and shape to some extent in A. stellata, but did not influence oospore number or size. Neither gemmae nor antheridia were induced to form. The specimens of Achlya spinosa reported and described briefly by Gepp (1899) were misidentified; they were without question A. radiosa. Minden’s A. stellata also was incorrectly named. We believe, as did Dick (1960b), that Minden’s plant was A. spinosa. The sparsely developed specimen that Humphrey (1893) described as Archer’s A. cornuta was in all probability A. stellata. Archer’s fungus, being parasitized, is excluded as a named species of Achlya.

CONFIRMED RECORDS: -- BRITISH ISLES: Dick (1960b:43, pl. 12, figs. 1-3; text figs. 1, 3, 4f-i. The legend to text figure 4 is in error; A. spinosa is represented in fig. 4f-i, 4 not 4i). GERMANY: de Bary (loc. cit.; 1888:647). MIDDLE EUROPE: Migula (1903:70). RECORDED COLLECTIONS: -- BRITISH ISLES: Apinis (1958, 1960, 1964); Dick (1963, 1966); Dick and Newby (1961); O’Sullivan (1965). FINLAND: Häyrén (1943-44, 1956). GERMANY: Höhnk (1956a). USSR: Logvinenko and Meshcheryakova (1971). SPECIMENS EXAMINED: -- Preserved specimen, de Bary collection, British Museum (Natural History). SWEDEN (1), TWJ. Centraalbureau (1), MWD (1); no oogonia were produced by these cultures.

Achlya colorata Pringsheim Sitzungsber. Deutsch. Akad. Wiss. Berlin, Math.-Naturwiss. Kl. 1882:855, 889, pl. 14, figs. 15, 17-31. 1882. (Figure 63 A-C)

Achlya racemosa var. stelligera Cornu, Ann. Sci. Nat. Bot. (5e sér.), 15:22. 1872. Achlya racemosa var. spinosa Cornu, ibid., p. 22. 1872. Achlya racemosa forma stelligera Petersen, Bot. Tidsskr., 29:383, fig. 3d. 1909. (Also in Ann. Mycol., 8: 522, fig. 3d. 1910.) Achlya racemosa forma pringsheimii Minden, Kryptogamenfl. Mark Brandenburg, 5:548. 1912. Achlya racemosa var. stelligera Minden non Cornu, ibid., p. 549. 1912. Achlya racemosa forma stelligera Minden, ibid., p. 549. 1912. Achlya racemosa var. stelligera forma polyspora Shkorbatov, Bot. Mater. Inst. Sporov. Rast. Glavn. Bot. Sada RSFSR, 2:35. 1923. Achlya racemosa forma pringsheimii Milovtsova, Trudy Inst. Bot. Kharkivs’kiĭ

486 Derzhavniĭ Univ., 1:34, pl. 4, fig. 11 1935.

Monoecious. Mycelium limited or moderately extensive, dense near substratum; hyphae slender, moderately branched near apices, sparingly branched elsewhere. Sporangia cylindrical, clavate, fusiform, or naviculate; straight, curved, or slightly irregular; renewed sympodially or cymosely, occasionally in a basipetalous fashion; 208-650 x 15-61 µm. Spores monomorphic; discharge and behavior achlyoid, rarely dictyucoid or aplanoid; primary spore cysts 9-12 µm in diameter. Gemmae abundant- cylindrical, or cylindrical and slightly irregular to obpyriform; terminal or intercalary, single or catenulate. Oogonia lateral, arranged in a racemose fashion, or occasionally terminal; spherical or obpyriform, rarely oval or obovate; (30-) 45-75 (-115) µm in diameter; inclusive of wall ornamentations. Oogonial wall pitted under area of attachment of antheridial cells, rarely elsewhere as well; sparsely or densely papillate or crenulate, very rarely smooth, rarely with one to a few spines; inner surface smooth or irregular. Oogonial stalks < ½ - 1 ½ (-5) times the diameter of the oogonium, in length; stout, straight or curved, often slightly irregular, unbranched or very rarely branched. Oospores occasionally not maturing; when mature, centric, spherical, or ellipsoidal; (1-) 2-8 (-24) per oogonium, and usually filling it or nearly so; (15-) 26-36 (-48) µm in diameter; at germination forming a short, unbranched germ hypha bearing a terminal, fusiform, or naviculate sporangium. Antheridial branches androgynous, very rarely exigynous; short and unbranched, or long and branched; 1-7 or more per oogonium, but usually one or two; slender, bent or curved, and often slightly irregular; persisting. Antheridial cells simple; clavate or cylindrical, usually strongly bent; persisting; apically appressed; fertilization tubes very rarely observed.

Achlya colorata has had a troubled history largely because of Pringsheim’s (1873-74) evident dissatisfaction with the names (and concepts) of Cornu’s A. racemosa var. stelligera and the variety spinosa. Pringsheim proposed the name colorata for Cornu’s plants, but inexplicably continued to refer to them as racemosa. In 1882(a) Pringsheim equated A. lignicola with A. colorata. No formal description of A. colorata emerged from Pringsheim’s juggling of the nomenclature; hence the first unequivocal reference to the species is limited to certain figures in his 1882(a) paper on sexual reproduction in Achlya and Saprolegnia. The varieties and forms of A. racemosa named by von Minden added nothing to an understanding of A. colorata. Finding both smooth and ornamented racemosely arranged oogonia on the hyphae of a watermold, A. Fischer (1892) concluded that A. racemosa and A. colorata were a single entity. Achlya colorata and A. racemosa do occasionally appear together on the same bait in gross culture, and could easily be taken as a single fungus. To the lengthy synonymy recorded by T. W. Johnson (1956b) for Achlya colorata we add the name A. racemosa forma pringsheimii, described in 1935(a) by Milovtsova. This form is identical with the A. racemosa forma pringsheimii of Minden (loc. cit.), and the one accompanying figure in Milovtsova’s account depicts the sexual apparatus of A. colorata.

487 The papillate ornamentations on the oogonia of Achlya colorata coupled with the androgynous antheridial branches and short stalks (Fig. 63 B, C) constitute the chief identifying characters of the species. Although it has been shown that the pattern of wall ornamentation in Achlya colorata is influenced by temperature, the characteristic still is reliable taxonomically. Reischer (1949c) demonstrated that as the temperature of incubation increased (cultures grown both on agar and in broth), the abundance and prominence of oogonial papillation decreased. At 25 oC, for example, roughened or smooth oogonia were produced, but only papillate ones developed in cultures incubated at 15 oC. In every broth culture of A. colorata, however, only rarely were there completely smooth oogonia (Reischer, 1949c). Temperature (and perhaps also the physical nature of the medium) influences the degree of wall ornamentations in this species, but not their presence or absence. Working with Achlya racemosa var. stelligera (=colorata) Moreau and Moreau (1935c) found that antheridial branches could convert functionally into vegetative hyphae or oogonia, and the latter into antheridial filaments. In 1927 P. M. Patterson demonstrated that fertilization occurred in A. colorata. This is the only species of watermold alleged to have bacterial “galls” in contaminated cultures (Moreau, 1946).

CONFIRMED RECORDS: -- BRITISH ISLES: E. M. Brown (1938:166); Gepp (1899: pl. 400, fig. 11). CANADA: C. L. Moore (1908-09:229, fig. 15). CZECHOSLOVAKIA: Cejp (1959a:178, figs. 59, 60). DENMARK: Petersen (loc. cit.). FRANCE: Cornu (loc. cit.); Moreau and Moreau (1938:233, pl. 3; pl. 6, figs. 10, 11; pls. 7-9, 11-19, 21, 24; fig. 1). GERMANY: Bock (1956:34, pl. 1); Minden (loc. cit.); Pringsheim (loc. cit; 1873-74: pls. 21; 22, figs. 1-3); Richter (1937:245). ICELAND: T. W. Johnson (1974b:7, figs. 97-99). POLAND: Szwanke (1938:10, pl. 4, figs. 3, 4); Zaborowska (1965:43, fig. 6). RUMANIA: Moruzi and Toma (1968: pl. 2, figs. 13-17; pl. 5, figs. 33, 34; fig. 13 on pl. 2 illustrates smooth oogonia; hence may not be this species). UNITED STATES: Beneke (1948b:61); Bretsynder (1943:12); Coker (1923:108, pl, 32); Humphrey (1893:123, pl. 19, figs. 96-98); T. W. Johnson (1956a:187; 1956b:23, pl. 2, figs. E-I); P. M. Patterson (1927: p1s. 8-10); Reischer (1949c: figs. 1-6); A. W. Ziegler (1948b:21, pl. 3, figs. 3-8; pl. 4, fig. 1; 1952: 10, pl. 4, fig. 10). USSR: Milovtsova (loc. cit.); Naumova (1955: 134, fig. 1); Shkorbatov (loc. cit.; 1927: 82). RECORDED COLLECTIONS: -- BRITISH ISLES: Apinis (1960, 1964); Cook and Forbes (1933); Dick (1962, 1963); Dick and Newby (1961); Forbes (1935a, (1965); Perrott (1960); R. E. Roberts (1963); Sparrow (1936); Willoughby (1962, 1974); Willoughby and Collins (1966). CANADA: Dick (1971c). DENMARK: A. Lund (1934). GERMANY: Höhnk (1935a, 1956a). INDIA: Dayal and Thakur Ji (1965, 1966); Thakur Ji (1967; 1970: 183, figs. 19-22; doubtful -- description and illustrations suggest A. racemosa). LATVIA: Apinis (1929a). NETHERLANDS: Beverwijk (1948). POLAND: Zebrowska (1976a). RUMANIA: Toma (1969, 1971). UNITED STATES: Clausz (1970, 1974); Coker (1927); Coker and Braxton (1926); Höhnk (1933); G .C. Hughes (1959, 1962); C. E. Miller (1965); Scott (1960b); Scott et al. (1963); Slifkin (1964, 1967a); Sparrow (1952b);

488 TeStrake (1958); M. W. Ward (1939); A. W. Ziegler (1958b). USSR: Logvinenko and Meshcheryakova (1971). SPECIMENS EXAMINED: -- ICELAND (14), NORWAY (4), TWJ. OCEANIA (2), RLS. UNITED STATES (5), TWJ, RLS. MWD (1).

Achlya papillosa Humphrey Trans. Amer. Phil. Soc. (N.S.) 17:125, pl. 15, fig. 28; pl. 20, figs. 99-102. 1893. (Figure 62 B-G)

Achlya spiracaulis Johnson, Mycologia 41:678, figs. 1, 2. 1949.

Monoecious. Mycelium extensive, diffuse; hyphae stout or slender, sparingly or moderately branched. Sporangia variable in abundance, often produced only at temperatures below 25 oC; fusiform, naviculate, cylindrical, or clavate; straight or curved; renewed sympodially or in basipetalous succession; 149-741 x 12-53 µm. Spores monomorphic, discharge and behavior achlyoid, rarely dictyucoid or aplanoid; primary spores 9-14 µm in diameter. Gemmae, when present, clavate, cylindrical, fusiform, naviculate, globose, subglobose, or obpyriform; occasionally with short, lateral protrusions distally; terminal or intercalary, single or catenulate; usually not disarticulating. Oogonia lateral or terminal, rarely intercalary; obovate, obpyriform, ovoid, spherical, or subspherical, infrequently asymmetrical, naviculate, cylindrical, clavate, obclavate, dolioform, or fusiform; (20-) 40-88 (-143) µm in diameter, nonspherical ones reaching 193 x 90 µm. Oogonial wall unpitted or pitted under region of attachment of the antheridial cells; densely or sparingly ornamented with short, broad papillae, occasionally with scattered, cylindrical to narrowly-conical protrusions; occasionally to rarely tuberculate. Oogonial stalks 1-12 times the diameter of the oogonium, in length; straight, bent, curved, recurved, loosely or tightly coiled, and usually noticeably irregular in outline; unbranched, occasionally to infrequently once- branched or with one to several short, lateral, cylindrical evaginations. Oospores centric; spherical or sometimes compressed from mutual pressure; (1-) 4-12 (-44) per oogonium, and filling it or not; (11-) 24-32 (-46) µm in diameter; at germination forming a slender, short, sparingly branched germ hypha bearing a small, terminal, clavate or fusiform sporangium. Antheridial branches, when present, androgynous or monoclinous, rarely or never diclinous; stout or slender, usually irregular; unbranched or branched; persisting. Antheridial cells, when produced, simple, cylindro-clavate, and slightly irregular; persisting, laterally or apically appressed; fertilization tubes present or absent, not persisting.

Achlya papillosa is closely allied structurally to A. oligacantha, and to no other species of Achlya having centric or subcentric oospores. The characteristics that separate these two species are treated in the account of A. oligacantha. In our experience, A. papillosa rarely is found in the New World, but is relatively more common in the Old

489 World. It is very prevalent in Iceland soils and waters, and we find it commonly, as well, in the southern Scandinavian Peninsula. Recognizing the structural proximity of Achlya spiracaulis T. W. Johnson, loc. cit.) to Humphrey’s A. papillosa, T. W. Johnson and Seymour (1974b) studied variation in nine isolates initially identified with one or the other of these two species. Each fungus was characterized in 17 parameters that, for the most part, were the same as those used by Dick (1969a) in his analysis of Scoliolegnia species. Six of the nine isolates subsequently were selected for further observation. These were propagated in a variety of culture conditions, and eight of the features most essential for the identification of the two taxa then were described for each colony. Incubation temperature and the source of culture water were the two variables. The degree and frequency of oogonial stalk coiling, and the abundance and prominence of oogonial wall ornamentations proved to be sensitive to culture conditions. Since it was precisely on these two features - of proven instability - that A. spiracaulis and A. papillosa had been separated, the two were necessarily merged (T. W. Johnson and Seymour, 1974b). The identification of Achlya papillosa collected in Poland by Stpiczyńska (1962) is probably incorrect, and the author herself seems to have been in doubt on this point. The configuration of the oogonia in her material was that of A. treleaseana (= androgyna), but in antheridial branch origin and the size of the oogonia and oospores, her specimens seem to have allied with A. papillosa or A. treleaseana, Stpiczynśka found only dictyucoid sporangia in the Polish material. The Achlya treleaseana recovered by Muhsin (1977) in Iraq was not that species, but rather A. papillosa. A specimen of A. papillosa generally having long, cylindrical oogonial wall ornamentations (in contrast to the papillate ones ordinarily encountered in Humphrey’s species) was reported by T. W. Johnson in 1956(a).

CONFIRMED RECORDS: -- AFRICA: Alabi (1967: pl. 12, fig. 3). ICELAND: Howard et al. (1970:67, figs. 23-25); T. W. Johnson and Seymour (1974b:446, pl. 1). IRAQ: Muhsin (1977:56, figs. A-E). JAPAN: S. Ito (1936: fig. 34.5); Nagai (1931:15, pl. 3, figs. 15- 18). SOUTH AMERICA: T. W. Johnson (1956b:29, pl. 3, figs. A, B). UNITED STATES: R. L. Butler (1975: figs. 125-128); Humphrey (loc. cit.); T. W. Johnson (loc. cit.; 1956a:187, figs. 8, 9; see also entry for South America). RECORDED COLLECTIONS: -- AFRICA: Alabi (1971b, 1973); Fajola et al. (1979). CANADA: Dick (1971c). GERMANY: Höhnk (1935a). ICELAND: T. W. Johnson (1968). JAPAN: Suzuki (1961f). POLAND: Stpiczyńska (1962: 106, fig. 8)(?). WEST INDIES: Sörgel (1941). SPECIMENS EXAMINED: -- ICELAND (12), TWJ. MWD (1).

Achlya oblongata var. oblongata deBary Bot. Zeitung (Berlin) 46:646, pl. 10, figs. 7-9. 1888 (Figures 60 I-L- 61 A, B)

490 Achlya oblongata var. globosa Humphrey, Trans. Amer. Phil. Soc. (N.S.) 17:122, pl. 19, figs. 90, 91. 1893.

Monoecious. Mycelium diffuse or moderately dense, extensive, hyphae stout, sparingly branched. Sporangia sparse; cylindrical, fusiform, or clavate; straight or curved, or with the distal portion attenuated and bent or irregular; renewed sympodially or cymosely, but in some individuals the sympodial branch terminates in an oogonium; 96-325 x 15-45 µm. Spores monomorphic; discharge and behavior achlyoid, occasionally aplanoid; spore cluster in some individuals falling away from the exit orifice; primary spore cysts 9-13 µm in diameter. Gemmae abundant; globose, obpyriform, cylindrical, fusiform, or irregular, occasionally branched; terminal or intercalary, single or catenulate. Oogonia lateral or terminal, rarely or occasionally intercalary, then single or catenulate; predominantly broadly obovate or obpyriform, occasionally spherical, dolioform, obpyriform, or cylindrical; seldom or rarely laterally bulged or constricted equatorially; immature ones rarely proliferating; obovate or obpyriform ones (58-) 80-148 (-183) x (49-) 65-94 (-133) µm; spherical ones (73-) 80-94 (- 118) µm in diameter; cylindrical, dolioform, or constricted ones (50-) 66-79 (-87) x (24-) 35-4l (-53) µm. Oogonial wall unpitted, pitted only under region of attachment of antheridial cells, or rarely very sparsely pitted elsewhere; in some large, obovate 1 oogonia wall is thin proximal to the septum; smooth. Oogonial stalks (1-) 1 ½ -2 /2 (-4) times the diameter of the oogonium, in length; stout; straight, curved, or slightly irregular; unbranched. Oospores infrequently or rarely reaching maturity; when mature, subcentric, but occasionally then quickly aborting; usually spherical, but ovoid, pyramidal, bacilliform, or ellipsoidal from mutual pressure or confines of lobed or bulged oogonia; (1-) 6-16 (-40) per oogonium, and usually not filling it; mature oospores (19-) 24-28(-50) µm in diameter, oospheres (9-) 22-28 (-70) µm in diameter; germination not observed. Antheridial branches diclinous; slender, irregular; usually sparingly branched; not persisting. Antheridial cells simple; small; tubular or clavate, occasionally irregular, infrequently lobed; persisting; laterally appressed; fertilization tubes not observed.

Achlya oblongata var. oblongata can be recognized by its large, predominantly obovate or obpyriform oogonia (usually not filled by oospheres or oospores), and its diclinous but quickly evanescent antheridial branches (Fig. 60 I-K). Most of the oospheres in the majority of oogonia do not mature, or if they do, the resulting oospores then may abort. De Bary’s fungus might be confused with A. irregularis at first glance, but representatives of that species have eccentric oospores. A characteristic in part diagnostic for A. oblongata var. oblongata, but one readily overlooked, is the persistence of the small, inconspicuous antheridial cells appressed to the oogonia after the antheridial branches have deliquesced. The few preserved specimens in the de Bary collection (British Museum, Natural History) display this condition (Fig. 61 A). Moreover, a few of the oogonia in de Bary’s material show one or two pits (not merely thin areas) in the wall. The species was originally described as being unpitted.

491 We are including in the circumscription of de Bary’s species the characteristics of five specimens recovered by T. W. Johnson (1974b: figs. 146-152) from Iceland soils. Since none of the isolates produced mature oospores, Johnson only provisionally identified the fungi as Achlya oblongata var. oblongata. His specimens formed some catenulate oogonia, and a few were bulged or lobed laterally. Although the oospheres were predominantly in the size range described for de Bary’s species, some were very small, and ovoid, cylindrical, or ellipsoidal (as well as spherical). The oogonia of the Iceland plants generally were noticeably larger than T. W. Johnson (1956b) had recorded for the species (in 1932, Rose provisionally identified as A. oblongata a watermold with very large oogonia). Antheridial branch origin and the deliquescent nature of those filaments in Johnson’s specimens from Iceland are undeniably identical to the condition encountered in Achlya oblongata var. oblongata. We are now satisfied after having again examined the Iceland collection that the fungi were merely forms of de Bary’s species digressing primarily in oogonium position and size, and failure of oospheres to mature. Certain miscellaneous taxonomic notes on de Bary’s species are in order. The reduction of Humphrey’s (loc. cit.) Achlya oblongata var. globosa to synonymous status with the variety oblongata was adequately justified by T. W. Johnson (1956b). Cejp (1959a: 172) regarded “A. oblongata var. oblongata Johnson “ (the varietal name was applied solely in conformity with nomenclatural practice) as a synonym of A. oblongata, along with Humphrey’s variety and Forbes’ (1935a) A. oblongata var. gigantica. Further on in his account, Cejp (1959a: 173, 174) treats the varieties oblongata and gigantea as mere variants. Although T.W. Johnson (1956b: 39) believed that Hamid’s (1942) specimen of A. oblongata (var. oblongata) was probably a misidentification of A. prolifera, Dayal and Thakur Ji (1968b) did not accept this view. Having no evidence to the contrary we are including the record by Hamid in A. oblongata var. oblongata as did Johnson. The description of A. oblongata by Chaudhuri et al. (1947) is at variance to some extent with the illustrations they provided, and their account of this species is accepted with skepticism. The citation to “Earle (1901)” in T. W. Johnson’s (1956b) account of de Bary’s species is incorrect; the paper was written by Mohr (1901) who simply repeated Atkinson’s (1897) record.

CONFIRMED RECORDS: -- AUSTRALIA: Crooks (1937:214, fig. 3A-D). BRITISH ISLES: R. A. Couch (1951:67, pls. 4-6); Forbes (1935a:230). CANADA: Maestres (1977:151, figs. 28-30). CZECHOSLOVAKIA: Cejp (1931:99; 1959a: 172, 173, figs. 56, 57). GERMANY: de Bary (loc. cit.); Bock (1956:37, pl. 3); Fischer (1892:354); Minden (1912:540); Schlösser (1929:538). ICELAND: T. W. Johnson (1974b:9, figs. 146- 152). INDIA: Dayal and Thakur Ji (1968b:239, figs. 8-13); J. N. Rai and Misra (1977b:73, fig. 1C). JAPAN: S. Ito (1936:87, figs. 33.3, 33.4, 34.6); Nagai (1931:24, pl. 3, figs. 19-21); Okane (1977:4, figs. E, F); Ookubo (1954:50, fig. 40). MIDDLE EUROPE: Migula (1903:70). POLAND: Stpiczyńska-Tober (1965:66, fig. 2). SOUTH AMERICA: Beroqui de Martinez (1970:112, fig. 2c). UNITED STATES: Coker 1923:132: pls. 46 (lower), 47);

492 Humphrey (1893:121, 122, pl. 19, figs. 87-91); Hutchison (1940:13, fig. 15); T. W. Johnson (1956b:37: pl. 5, figs. E-J); Rose (1932:39, pl. 4, fig. 36). USSR: Morochkovs’kiĭ et al., (1967:139, fig. 126). RECORDED COLLECTIONS: -- BRITISH ISLES: Cook and Forbes (1933); Forbes (1935b); Hunter (1975); R. E. Roberts (1963). CANADA: D. L. McKay (1967); Maestres and Nolan (1978). FRANCE: Volkonsky (1934). GERMANY: Höhnk (1935a, 1953b); Stoll (1936). INDIA: Chaudhuri et al. (1947: 50, fig. 22)(?); Hamid (1942: 209, pl. 1)(?). JAPAN: Hoshina et al. (1958); Okane (1978); Suzuki (1961f, i). UNITED STATES: Atkinson (1897); R. L. Butler (1975)(?); Coker and Braxton (1926); W. B. Cooke and Bartsch (1959, 1960); T. W. Johnson (1956a); Klich (1980); R. L. Martin (1968a); Monsma (1936); Rooney and McKnight (1972); Schmitt (1967); Slifkin (1964); TeStrake (1958); A. W. Ziegler (1958b). USSR: Érgashev and Kirgizbaeva (1978); Logvinenko (1971); Logvinenko and Meshcheryakova (1971); Meshcheryakova (1974). SPECIMENS EXAMINED: -- Preserved specimens, de Bary collection, British Museum (Natural History) (Germany). ICELAND (5), NORWAY (1); TWJ; UNITED STATES (1), TeStrake.

Achlya oblongata var. gigantica Forbes Trans. Brit. Mycol. Soc. 19:231, pl. 8, fig. 3. 1935

“Growth 2 cm. or more. Hyphae up to 150 µ at the base. Sporangia as in the species. Spores, diameter 12.5 µ when encysted. Oogonia in racemes on long lateral branches; oblong, pear-shaped or cylindrical; often with a pointed apex, walls unpitted; very large, 90-250 x 50-100 µ. Oospores 1-8 per oogonium; wall about 2 µ thick; 36-49 µ diameter; frequently not maturing; very dark when young, and structure difficult to observe, subcentric. Antheridia diclinous, on most oogonia.” (Forbes, loc. cit.)

As described by its author, this variety of Achlya oblongata should be easily recognized and separated from the variety oblongata. The large oogonia and oospores set off the variety gigantica readily from the variety oblongata. Forbes illustrated faintly apiculate oogonia for her variety gigantica, and while we have not seen such cells in our specimens of the variety oblongata, Humphrey (1893: pl. 19, fig. 88) depicted a similar oogonium from his material of de Bary’s species. Subcultures of Forbes’ fungus examined by T. W. Johnson (1956b) were parasitized by a holocarpic, endobiotic chytrid, and thus were of dubious value as specimens on which to base taxonomic judgments. It is not likely that Forbes, being a careful observer of many zoosporic fungi, would have described a new taxon on the basis of infected specimens. The variety must therefore be considered valid in the absence of any contradictory evidence. Although the Iceland specimens identified by T. W. Johnson (1974b) as the variety oblongata approached Forbes’ variety in oogonial size, the oospores were generally smaller than reported for Achlya oblongata var. gigantica. Whether or not this difference will be found to persist in the characterization of future isolates of A. oblongata remains to be seen.

493 Muhsin (1977) reported the recovery of six specimens of Achlya oblongata var. gigantica from Iraq soils. In these watermolds the oospores were even larger (40-62 µm in diameter) than had been described for this variety (Forbes loc. cit.). Muhsin did not characterize or illustrate the oogonia produced by his fungi, but did refer to the tendency of the antheridial branches to deliquesce. The latter character certainly strengthens the identification.

CONFIRMED RECORDS: -- BRITISH ISLES: Forbes (loc. cit.). IRAQ: Muhsin (1977:55, figs. A-C). SPECIMENS EXAMINED: -- UNITED STATES (1), RLS; unable to isolate from gross culture. MWD (1), from Centraalbureau; isolate did not produce sexual apparatus.

Achlya oligacantha de Bary Bot. Zeitung (Berlin) 46:647, pl. 10, fig. 1. 1888 (Figures 62A; 63 D-L)

Achlya oligacantha var. brevispina Shkorbatov, Bot. Mater. Inst. Sporov. Rast. Glavn. Bot. Sada RSFSR 2:36. 1923.

Monoecious. Mycelium diffuse; hyphae slender, moderately branched near periphery of colony, and sparingly branched elsewhere. Sporangia very sparse or rare; cylindrical or fusiform, straight, curved, bent, or slightly sinuous; renewed sympodially; 280-765 x 24-36 µm. Spores monomorphic; discharge and behavior achlyoid; spore cluster persisting at exit orifice or falling away; primary spore cysts 9-12 µm in diameter. Gemmae absent. Oogonia lateral or terminal, rarely intercalary; predominantly obpyriform or obovate, often spherical, occasionally ovoid, rarely angular, dolioform, or apiculate; (48-) 70-90 (-180) x (38-) 60-80 (-16l) µm, spherical ones (45-) 70-87 (-124) µm in diameter; including wall ornamentations. Oogonial wall unpitted, sparsely pitted, or with a few broad, circular, thin areas on inner surface; smooth, but occasionally to infrequently sparsely papillate, or with a very faint, crenulate aspect. Oogonial stalks (1/8-) 2-3 (-8) times the diameter of the oogonium, in length; stout; usually curved or irregular, infrequently to rarely bent or sparingly coiled, rarely straight or branched. Oospores very infrequently or only rarely maturing, or forming but then quickly aborting; centric or subcentric; spherical; (1-) 10-16 (-28) per oogonium, and only occasionally filling it; (14-) 20-28(-44) µm in diameter; germination not observed. Antheridial branches predominantly monoclinous, infrequently diclinous, and rarely androgynous; moderately stout; usually irregular, unbranched or branched, or with stout, cylindrical evaginations; persisting. Antheridial cells simple; clavate or tubular, occasionally irregular; persisting; laterally appressed; fertilization tubes usually absent, when formed may or may not persist.

Achlya oligacantha is not a watermold species that can be recognized quickly because of the rather marked degree of variation among individuals. Isolates grown in

494 40-50 mL of charcoal-filtered, distilled water or tap water are the least variable, in our experience. Recognition of Achlya oligacantha generally must be based on a combination of three structural features: obovate or obpyriform oogonia that are smooth (or only infrequently display a few inconspicuous papillae) and usually contain 10-14 oospheres distributed loosely within the oogonial cavity. There are in addition other characteristics secondarily useful in identifying this species. In all the specimens we have examined, monoclinous antheridial branches clearly predominate (Fig. 62A). When the oospheres mature -- and they very seldom do -- the resulting oospores are centric with one or two rows of refractive droplets. In exceptional instances (Fig. 63 J) the wall projections are relatively abundant, but never is the oogonium densely papillate as in some of the eccentric-egged species of Achlya. The oogonial stalks -- noticeably irregular (Fig. 63 D, E) -- may be coiled (recalling the usual condition in A. papillosa (Fig. 62 E, F), but only infrequently. Isolates of Achlya oligacantha with predominantly smooth, obpyriform to obovate oogonia resemble superficially specimens of A. oblongata var. oblongata. Oogonia of the latter are not ornamented, and the attendant antheridial branches are exclusively diclinous so far as is known. The antheridial filaments of A. oligacantha persist; they seldom do so in A. oblongata var. oblongata. Although T. W. Johnson (1956b) recognized the resemblance of his Achlya spiracaulis (=papillosa) to A. oligacantha, he maintained that the two could be separated readily. Later, however, he (T. W. Johnson, 1974b) was less sure of recognizable differences between the two, a view also generated by the results of an extensive analysis of elements of the A. spiracaulis /A. papillosa complex by T. W. Johnson and Seymour (1974b). Some of the isolates they examined had sparsely papillate or smooth oogonia and a low frequency of oogonial stalk coiling, and in these respects the specimens showed an alliance with de Bary’s species. Johnson and Seymour concluded that heaviest weight might have to be given to the single character, in A. oligacantha, of failure of oospheres to mature, if it was to remain separated from A. papillosa. The results from some simple culture manipulations (T. W. Johnson, 1974b) in growing Achlya oligacantha are pertinent to the question of the status of the species. Oogonia on mycelium propagated at 18 oC in autoclaved pond water varied widely in the frequency and prominence of their wall ornamentations. In none of the oogonia, however, were the papillae as dense as is common in A. papillosa. When grown at 25 oC, in autoclaved pond water–soil extract medium, specimens of A. oligacantha produced only smooth or very sparsely papillate, spherical or ovoid oogonia. In the pond water- soil extract medium at 18 oC, however, the fungus developed large, obovoid, obpyriform, or angular oogonia with fewer (4-6, 70% median) oospores than is usual (10-16) for the species. Moreover, in these same cultures, the antheridial filaments and oogonial stalks (as well as some hyphal branches) were often twisted, contorted, or even loosely and irregularly coiled (T. W. Johnson, 1974b: figs. 131, 132). Antheridial branch origin, oogonial wall pitting, degree of oosphere maturation, and type of oospore were not modified by changes in the culture environment. This study confirmed what had

495 earlier been suspected, namely, the variability of A. oligacantha in oogonial wall ornamentation and stalk configuration. The reaction of specimens of this species, however, was not in the direction of A. papillosa, thus strengthening the view that the two are not expressions of a single taxon. Variants of Achlya oligacantha have been described from time to time. Ookubo’s (1954) specimen had more abundant antheridial filaments than any representatives we have seen of this species. Cejp (1959a) illustrated centric and subcentric oospores for de Bary’s species, and Milanez and Beneke (1968) found both types in their material. Earlier, Milanez (1966) reported that A. oligacantha had subcentric oospores. We have seen only centric oospores in our collections. Irregular oogonia are illustrated by Dayal and Thakur Ji (1965) for A. oligacantha. That Shkorbatov’s variety brevispina was properly disposed of by T. W. Johnson (1956b) by it’s merger with Achlya oligacantha is confirmed by the characteristics and variations in the Iceland specimens (T. W. Johnson, 1974b).

CONFIRMED RECORDS: -- CZECHOSLOVAKIA: Cejp (1959a:187, fig. 65). DENMARK: A. Lund (1934:27, fig. llb-d); Petersen (1909a:385). GERMANY: de Bary (loc. cit.); A. Fischer (1892:354). ICELAND: T. W. Johnson (1974b:10, figs. 119-133). INDIA: Dayal and Thakur Ji (1965:317, pl. 3). JAPAN: Ookubo (1954:53, fig. 41). MIDDLE EUROPE: Migula (1903:70). NETHERLANDS: Beverwijk (1948:239, fig. 6). POLAND: Staniak (1971:362). UNITED STATES: T. W. Johnson (1956a:187; 1956b: 31, pl. 8, figs. A-F); Milanez (1966:83); Milanez and Beneke (1968:16). USSR: Morochkovs’kiĭ et al. (1967:141, fig. 128); Shkorbatov (loc. cit.; 1927: 83). RECORDED COLLECTIONS: -- BRITISH ISLES: Haines (in, Beverwijk, 1948); Hunter (1975); R. E. Roberts (1963). DENMARK: Petersen (1910). GERMANY: Stoll (1936). INDIA: Dayal and Thakur Ji (1966); Thakur Ji (1967). JAPAN: Suzuki (1961f). UNITED STATES: TeStrake (1958). USSR: Dudka (1965, 1966); Logvinenko and Meshcheryakova (1971). SPECIMENS EXAMINED: -- ICELAND (7), NORWAY (2), TWJ; UNITED STATES (3) TeStrake, RLS. MWD (1) –- isolate did not produce sexual apparatus.

Achlya megasperma Humphrey Trans. Amer. Phil. Soc. (N.S.) 17:118, pl. 18, figs. 74-77.1893 (Figure 60 E-H)

Monoecious. Mycelium extensive, diffuse; hyphae stout, sparingly branched. Sporangia cylindrical, clavate, or fusiform; straight, curved or slightly sinuous; renewed sympodially, cymosely, or in basipetalous succession; 95-1005 x 21-48 µm. Spores monomorphic; discharge and behavior achlyoid; primary spore cysts 10-13 µm in diameter. Gemmae abundant; cylindrical, fusiform, or clavate; occasionally branched; terminal or intercalary, single or catenulate; occasionally disarticulating. Oogonia lateral, infrequently terminal; spherical or obpyriform, occasionally oval, infrequently obovate, very rarely slightly angular or apiculate; (33-) 70-90 (-170) µm in diameter.

496 Oogonial wall unpitted or very sparingly pitted; often or only infrequently irregular on inner surface, with noticeable thin regions; smooth. Oogonial stalks (1/2-) ¾ -1 (-3) times the diameter of the oogonium, in length; stout, straight or only slightly curved; occasionally slightly irregular; unbranched. Oospores subcentric; spherical, ellipsoidal, or pyramidal from mutual pressure; (1-) 2-6 (-12) per oogonium, and usually filling it; (30-) 44-52(-66) µm in diameter; germination not observed. Antheridial branches diclinous, occasionally to infrequently androgynous or monoclinous; occasionally not attaching to oogonia; slender, irregular; short or long; unbranched or sparingly branched; persisting. Antheridial cells frequently or only occasionally not formed; when present, cylindrical, clavate, irregular or once-lobed; persisting; attached in a digitate manner; fertilization tubes usually present, persisting.

Although Achlya megasperma shares with several neighboring species the characteristic of spherical or obpyriform, short-stalked oogonia, it has noticeably larger oospores than any recognized taxon in the genus except A. oblongata var. gigantica. If, as T. W. Johnson (1956b: 116) implied, Viégas and Teixeira (1943) were incorrect in identifying the oospores of their Achlya sp. as eccentric, there is every good reason for merging that unnamed species with A. megasperma. The recovery from Iceland soil of a fungus tentatively identified as Achlya megasperma was reported by T. W. Johnson in 1974(b). His isolate lacked sporangia, but in all other characters matched Humphrey’s species. We are now convinced that the Iceland specimen was a variant A. megasperma (Fig. 60 E, G).

CONFIRMED RECORDS: -- BRITISH ISLES: Forbes (1935a: 231). GERMANY: Bock (1956:34, pl. 2, fig. 3). ICELAND: T. W. Johnson (1974b:9). JAPAN: S. Ito (1936:86, fig. 35); Nagai (1931:23, pl. 6, figs. 3-10); Okane (1977:4, figs. C. D). RUMANIA: Toma (1969:217, pls. 3,7). UNITED STATES: Coker (1923:128, pl. 44); Humphrey (loc. cit.); A. W. Ziegler (1952:9, pl. 4, fig. 1). WEST INDIES: T. W. Johnson (1956b:36, pl. 8, figs. G-J). RECORDED COLLECTIONS: -- AFRICA: Alabi (1967, 1971a, b; 1973). BRITISH ISLES: Cook and Forbes (1933); Dick (1963, 1966); Dick and Newby (1961); Hunter (1975); Park (1974)(?); R. E. Roberts (1963). CANADA: Dick (1971c). GERMANY: Höhnk (1935a). JAPAN: S. Ito and Nagai (1931); Okane (1978); Suzuki (1960d, 1961f); Suzuki and Tatsuno (1964, 1965b). UNITED STATES: T. W. Johnson (1956a); C. E. Miller (1965); Schmitt (1967); Slifkin (1964); M. W. Ward (1939); A. W. Ziegler (1958b). SPECIMENS EXAMINED: -- ICELAND (1), TWJ; WEST INDIES (1), F. K. Sparrow.

Achlya bonariensis Beroqui Darwiniana 15:9, fig. l C-F; pl. 1, figs. A, B. 1969

Monoecious. Mycelium flexuous; hyphae sinuous. Sporangia rare, fusiform or cylindrical; renewed sympodially; 100-560 x 7-70 µm. Spores monomorphic; discharge and behavior achlyoid; primary spore cysts 10-12 µm in diameter. Gemmae abundant;

497 variable in shape; cylindrical, obpyriform, unbranched or branched; terminal or intercalary, single or catenulate. Oogonia lateral; spherical, subspherical, obpyriform, or ovoid, occasionally apiculate; (10-) 30-50 (-90) µm in diameter. Oogonial wall pitted or pitted only under region of antheridial cell attachment; smooth, or with an apiculus, or 1-2 papillae. Oogonial stalks 10-90 µm long; straight or curved; unbranched or in exceptional instances branched. Oospores subcentric; spherical, 1-3 (-7) per oogonium and generally not filling it; (12-) 21-24 (-39) µm in diameter; germination not observed. Antheridial branches, when present, diclinous or rarely monoclinous; long, sinuous, branched. Antheridial cells simple, cylindrical or slightly clavate; laterally appressed; fertilization tubes seldom visible. (Adapted from Beroqui de Martinez, loc. cit.)

Save for oospore structure, all of the principal characters of Achlya bonariensis are ones clearly attributable to A. caroliniana, and the illustrations are unequivocal in this regard. The oospores of the Argentinian fungus are subcentric (depicted in fig. l E accompanying the original description), while those of A. caroliniana are eccentric. We are inclined to merge the two taxa, but that would violate harshly the concept of A. caroliniana (no species of watermold is known to produce both centric and eccentric oospores). We have not seen any specimens of A. bonariensis, and cannot confirm that it has the oospore structure attributed to it. In all other respects, it is A. caroliniana, and may prove to be this species if it can be again recovered and examined thoroughly. Beroqui de Martinez (loc. cit.) believed her species to be near A. W. Ziegler’s (1958a) Achlya mucronata (a species of Protoachlya). She was correct in not equating A. bonariensis with his species since the oogonial wall ornamentation patterns in the two are very different (to say nothing of the planont behavior at release).

CONFIRMED RECORD: -- SOUTH AMERICA: Beroqui de Martinez (loc. cit.).

Achlya polyandra Hildebrand Jahrb. Wiss. Bot. 6:58, pl. 16, figs. 7-11. 1867-68 (Figure 61 C-F)

Achlya gracilipes de Bary, Bot. Zeitung (Berlin) 46:635; pl. 10, figs. 2, 6. 1888.

Monoecious. Mycelium extensive, diffuse; hyphae stout, moderately branched. Sporangia sparse; cylindrical, fusiform, or clavate; straight or slightly irregular, rarely strongly bent; renewed sympodially; 80-l090 x 15-52 µm. Spores monomorphic; discharge and behavior achlyoid, infrequently aplanoid; primary spore cysts 9-12 µm in diameter. Gemmae sparse; cylindrical, fusiform, obpyriform, or irregular, occasionally with one or two lateral, cylindrical) or papillate protrusions at the ends; terminal or intercalary, single or catenulate. Oogonia lateral, infrequently terminal; obpyriform, occasionally spherical, rarely oval; (40-) 15-90 (-113) µm in diameter. Oogonial wall unpitted or rarely only sparsely pitted; smooth. Oogonial stalks (1-) 2-3 (-5) times the diameter of the oogonium, in length; stout or slender; curved, slightly irregular or

498 sinuous, infrequently straight, unbranched. Oospores infrequently reaching maturity, but subcentric when fully formed; spherical; (3-) 8-14 (-24) per oogonium, and filling it or not; (l5-) 25-28(-36) µm in diameter; germination not observed. Antheridial branches androgynous, rarely monoclinous; slender, irregular or twisted, sparingly or abundantly branched; persisting. Antheridial cells simple; tubular or clavate; persisting; laterally appressed; fertilization tubes not observed.

The two main characters by which Achlya polyandra is recognized are the long oogonial stalks and the prominent, usually abundant, androgynous antheridial filaments (Fig. 61 C-E). The oogonia are generally rather large, and because they are predominantly obpyriform (Fig. 61 F), they resemble the female sexual apparatus of A. oligacantha and, to some extent, that of A. oblongata var. oblongata. However, in the last named variety, the antheridial branches are diclinous (which we have never observed in A. polyandra, and in A. oligacantha, monoclinous rather than androgynous branches prevail. Moreover, A. oligacantha has some ornamented oogonia, but such sex cells are unknown for Hildebrand’s species. The name polyandra was applied to two species in Achlya one authored by Hildebrand (loc. cit.), the other by de Bary (1881). Humphrey (1893) provided the new name debaryana for de Bary‘s A. polyandra, and at the same time properly reduced A. gracilipes de Bary (loc. cit.) to synonymy with Hildebrand’s A. polyandra. The name Achlya polyandra de Bary and A. polyandra Hildebrand were used interchangeably and therefore incorrectly by some early mycologists. These cases are cited fully by T. W. Johnson (1956b). For example, Hine’s (1878) A. polyandra was neither de Bary’s species nor Hildebrand’s taxon but represented what Humphrey was to describe later as A. americana. The description and illustrations by Kobayashi and Okubo (1954:569, fig. 11) of Aplanes sp. do not permit precise identification of their fungus, but we suggest they had collected a variant of Achlya polyandra Hildebrand. The general aspect of the sexual apparatus in Aplanes sp. recalls that of A. polyandra, and the two are similar in that both may exhibit some aplanoid sporangia. Having no more than circumstantial evidence, we are not including Aplanes sp. as a record of Hildebrand’s species, but suspect that this would be a proper disposition for it.

CONFIRMED RECORDS: -- BRITISH ISLES: Massee (1891:138, pl. 2, fig. 31). CANADA: C. L. Moore (1908-09:226, fig. 9). CZECHOSLOVAKIA: Cejp (1959a:167, figs. 52, 53). DENMARK: Petersen (1909a:384, fig. 3g; 1910:524, fig. 3g). GERMANY: de Bary (loc. cit.; 1888:634); A. Fischer (1892:351); Hildebrand (loc. cit); Lindstedt (1872:23 et seq.); Pringsheim (1873-74:203 et sqq., pl. 17; pl. 18, figs. 1-4; pl. 20, figs. 4-11; pl. 22, figs. 4, 5; 1882a:861 et sqq., pl. 14, figs. A 1-11, 13, 14, 16); Richter (1937: 251). ICELAND: T. W. Johnson (1974b:12, figs. 100, 101). INDIA: J. N Rai and Misra (1977b:75, fig. ld). IRAQ: Muhsin (1977:60, figs. A-C). MIDDLE EUROPE: Migula (1903:69). POLAND: Staniak (1971:362); Stpiczyn’ska-Tober (1965:64, fig. 1). UNITED STATES: Humphrey (1893:119,

499 pl. 15, fig. 23; pl. 18, figs. 78-81); T. W. Johnson (1956b:40, pl. 4, figs. C-1); Rose (1932:37, pl. 3, figs. 23, 24). USSR: Dudka and Logvinenko (1968: fig. 1.3); Florinskaya (1969:114, fig. 10); Naumov (1954:70). RECORDED COLLECTIONS: -- BRITISH ISLES: Apinis (1964); Cook and Forbes (1933); Cook and Morgan (1934); Forbes (1935a, b); Hartog (1886-87; 1895); R. E. Roberts (1963); Trow (1904). DENMARK: A. Lund (1934). FINLAND: Häyrén (1902-03, 1943-44, 1956). FRANCE: Volkonsky (1934). GERMANY: Höhnk (1935a); Stoll (1936). HUNGARY: Moesz (1937-38). INDIA: Butler and Bisby (1931); Chaudhuri et al. (1947); J. N. Rai and Misra (1977b). IRAQ: Al-Saadi et al. (1979). LATVIA: Apinis (1929a). RUMANIA: Moruzi and Toma (1968: pl. 3, fig. 27); Toma (1969?, 1971). SWITZERLAND: Maurizio (1895d)(?). UNITED STATES: Beneke and Schmitt (1961); Kauffman (1906). USSR: Florinskaya (1971); Logvinenko (1971); Logvinenko and Meshcheryakova (1971); Mil’ko (1965); Mil’ko and Belyakova (1968); Shcherbak’, (1910); Yachevskim’ (1895). SPECIMENS EXAMINED: -- AUSTRALIA (1), RLS. ICELAND (5), SWEDEN (2), TWJ. MWD (1); specimen did not produce oogonia or antheridia.

Achlya racemosa Hildebrand Jahrb. Wiss. Bot. 6:249, pl. 15. 1867-68 (Fig. 66 E-H)

Achlya lignicola Hildebrand, Jahrb. Wiss. Bot. 6:255, pl. 16, figs. 1-6a. 1867-68. Achlya racemosa forma lignicola (Hildebrand) Pringsheim, Jahrb. Wiss. Bot. 9:205. 1873- 74. Achlya colorata Pringsheim, Sitzungsber. Deutsch. Akad. Wiss. Berlin, Math.-Naturwiss. Kl. 1882:889, pl. 14, fig. 12. 1882. Achlya racemosa f. maxima Minden, Kryptogamenfl. Mark Brandenburg 5:548. 1912. Achlya racemosa var. lignicola (Hildebrand) Coker, , p. 107. 1923. Achlya sparrowii Reischer, Mycologia 41:339, figs. 2-5. 1949. Achlya racemosa var. maxima (Minden) Cejp, I, Flora CSR, Ser. B, Part 2, p. 186, fig. 64. 1959.

Monoecious. Mycelium limited to extensive, moderately dense; hyphae stout, sparingly branched. Sporangia abundant or rare; cylindrical or clavate, straight or slightly irregular, very rarely branched; renewed sympodially or in basipetalous succession; 135-1015 x 15-45 µm. Spores monomorphic; discharge and behavior achlyoid; primary spore cysts 8-12 µm in diameter. Gemmae, when present, usually abundant; cylindrical, irregular, or branched; terminal or intercalary, single or catenulate. Oogonial lateral and usually racemosely arranged, occasionally terminal, very rarely intercalary; spherical or obpyriform; (22-) 40-80 (-121) µm in diameter. Oogonial wall pitted or unpitted; smooth on outer surface, slightly irregular on inner 1 surface, or unevenly deposited. Oogonial stalks ( /4-) 1-1 ½ (-6) times the diameter of the oogonium, in length; slender or relatively stout; straight, curved or sigmoid, or

500 slightly irregular. Oospores centric or subcentric; spherical or occasionally ellipsoidal; (1-) 2-6 (-14) per oogonium, and usually not filling it; (14-) 23-28 (-38) µm in diameter; at maturation forming a slender, unbranched germ hypha bearing a small, terminal, cylindrical sporangium. Antheridial branches predominantly androgynous, infrequently exigynous, extremely rarely diclinous; short, slender, curved or irregular; rarely branched; persisting. Antheridial cells simple; clavate, but usually strongly bent or curved; persisting; apically appressed, fertilization tubes produced, not persisting.

Achlya racemosa is an easily recognized species, although the foregoing listing of synonyms might suggest otherwise. The smooth, short-stalked, racemosely arranged oogonia (Fig. 66 E) usually are attended by one or two short, curved, androgynous antheridial branches (Fig. 66 F). Achlya colorata has a similar configuration but in that species the oogonia generally are papillate. Certain variations in the structure and growth of Achlya racemosa have been recorded, as, for example, in wall pitting (Hine, 1878; T. W. Johnson, 1973a), sporangium length at certain incubation temperatures (Rose, 1932), and suppression of antheridial branches (T. W. Johnson, 1956a) when isolates are grown on various substrates. An unusual pattern of spore behavior was reported in 1933 by Höhnk. He found that a spore of A. racemosa could produce a short germ hypha terminated by a functional sporangium containing one or two spores, each of which emerged subsequently from the miniature germ hypha sporangium as a laterally biflagellate cell. Willoughby (1977) discovered a somewhat similar abbreviated asexual cycle in an isolate of Saprolegnia. The most unusual sexual form of A. racemosa known was recovered by T. W. Johnson (1973a) from two samples of Iceland soil. These specimens produced the usual type of sex cell configuration in A. racemosa, but also developed suboogonial branches (from the lateral stalk) that either functioned as antheridia, or matured into satellite oogonia (Fig. 66 H). As many as 48 such miniature oogonia appeared on some oogonial stalks. Generally, the satellite oogonia contained one subcentric or centric oospore, but in a very few instances two or three were developed. This form has been discussed in Chapter 9. Working with Achlya colorata (as A. racemosa var. stelligera) Moreau and Moreau (1935c) demonstrated that functional changes occurred in the antheridial branches and oogonial initials and stalks. For example, an androgynous antheridial branch could produce a terminal oogonium, and lateral branches from an oogonial stalk were capable of forming oogonia. The functional “reversal” that Johnson found in A. racemosa, then, is not unique to that species. The discoveries by Moreau and Moreau (1935c) and T. W. Johnson (1973a) provide further evidence for the close kinship of A. racemosa and A. colorata. Depending solely on stained cytological preparations for data, Dayal and Thakur Ji (1973) studied the behavior of vegetative nuclei in Achlya racemosa during mitosis. They found neither a spindle apparatus nor chromosomal filaments (microtubules?) associated with dividing nuclei, nor any alignment of chromatin on a

501 metaphase plate. Achlya prolifera and A. aquatica had an identical pattern of mitotic division. Borkowski (1972) used A. racemosa in his singular investigation of axial arrangement of discharging spores in watermolds. The nomenclature of Achlya racemosa after its discovery by Hildebrand (locc. citt.) became confused, largely through the reports by Hildebrand himself, and in particular by the accounts published by Pringsheim (1873-74; loc. cit.). There is no doubt that Hildebrand’s A. lignicola was only a variant of A. racemosa, but not one commanding varietal rank as Coker (loc. cit.) thought. Only one figure in Pringsheim’s lengthy treatise (loc. cit.) on sexuality in watermolds represents Hildebrand’s species; the others in that account very likely are of A. colorata. Vishniac and Nigrelli (1957) did not accept T. W. Johnson’s (1956b) reduction of A. sparrowii to equal status with A. racemosa. They argued that their species had subcentric oospores whereas A. racemosa produced centric ones (Johnson did not mention egg structure in his attempt to justify his disposition of Reischer’s species). It is now known, of course, that A. racemosa can produce both types (T. W. Johnson, 1973a). In this connection, the study by B. R. Green and Dick (1973) may be cited. They demonstrated that the DNA base composition values for A. racemosa and A. sparrowii predicted a very close relationship between the two. Green and Dick also determined that A. racemosa had a chromosome number of N = ca. 11-12, and A. sparrowii N = ca. 12-13 (both species ca. 12, according to Dick, 1978). A few accounts in the literature pertaining to Achlya racemosa require specific comment. Both Nagai (1931) and T. Ito (1944) list Takahashi’s (1918) report of A. prolifera as a record of Hildebrand’s species. The descriptive notes provided by Takahashi give the impression that he had not collected A. prolifera; they give even less assurance that he had found A. racemosa. Hine (1878:140) collected on submerged twigs of Pinus strobus L. a fungus which he designated as “A. racemosa var.” He proposed that this unnamed variety, A. racemosa, and A. lignicola be merged under one epithet, A. variabilis. The figures given by Thakur Ji (1970: figs. 19-25) to illustrate A. colorata are of A. racemosa. Perhaps Thakur Ji separated these two species merely on the basis of whether the inner wall surface of the oogonium was smooth or irregular. The A. racemosa reported from India by J. N. Rai and Misra (1977b: 75, fig. 2a) was not this species. Their account makes no mention of androgynous antheridial branches, and the descriptive information suggests that they may have collected A. oligacantha. Cejp (1959a) published some nomenclatural changes in A. racemosa, particularly at the varietal level, but in light of additional observations, the proposed names were not necessary.

CONFIRMED RECORDS: -- AFRICA: Alabi (1967: pl. 12, fig. 1); El-Hissy (1974: pl. 2, fig. d). AUSTRALIA: Cookson (1937: 241). BRITISH ISLES: E. M. Brown (1938:166); R. A. Couch (1951:80, pls. 9, 10); Gepp (1899: pl. 400, figs. 9, 10). CANADA: C. L. Moore (1908-09:228, fig. 14). CZECHOSLOVAKIA: Cejp (1932:12, figs. 1-3; loc. cit., 1959a:182, 185, figs. 61-63). DENMARK: A. Lund (1934:23); Petersen (1909a:382, figs. 3d, i; 1910:522, figs. 3d, i). EAST GERMANY: Borkowski (1972: figs. lb, 2, 3, 5, 6c-f, 7a). FRANCE: Cornu (1872: pl. 1, figs. 2-8). GERMANY: de Bary (1888:645); A. Fischer

502 (1892:347, fig. 54a); Hildebrand (locc. citt.); Mackel (1928: figs. 3a, b); Minden (1912:547, 548, fig. 2a); Pringsheim (locc. citt.); Reinsch (1878, pl. 14, fig. 12); Richter (1937:244); Zopf (1890:296). ICELAND: T. W. Johnson (1973a:440 et sqq., fig. 1). INDIA: Shah et al. (1977:143); Thakur Ji (1970:183, figs. 19-25). IRAQ: Muhsin (1977:52, figs. A-D). JAPAN: Indoh (1937:297, pl. 14, figs. 1-6); S. Ito (1936:81, figs. 33.7, 33.8; 1942:125); T. Ito (1942:125); Kobayashi and Ôkubo (1954:565, fig. 5); Nagai (1931:13, pl. 3, figs. 9-14); Okane (1977:4, figs. G, H). MIDDLE EUROPE: Migula (1903:68, pl. 2B, fig. 1). NEPAL; Joshi (1976:42, fig. 1). NEW GUINEA: Kobayasi and Konno (1973:500, fig. 10 A-F). PEOPLE'S REPUBLIC OF CHINA: Shen and Siang (1948:193). POLAND: Stpiczyńska- Tober (1965:67, fig. 3). RUMANIA: Moruzi and Toma (1968: pl. 2, figs. 11, 12, 13(?); pl 5, fig. 35). SOUTH AMERICA: T .W. Johnson (1956b:21, pl. 2, figs. A-D). UNITED STATES: Beneke (1948b:60); Bretsnyder (1943:12); R. L. Butler (1975: figs. 77-80); M. C. Carlson (1929: pl. 4); Coker (1923:106, pls. 14, 31); Graff (1928:173); Hine (1878:140 et sqq., pl. 6, figs. 1-14; pl. 7, figs. 1-3); Humphrey (1893:122, pl. 14, fig. 4; pl. 19, figs. 92- 95); Hutchison [1940: 14, fig. 14 (misidentified as A. colorata)]; T. W. Johnson (1956a:189, figs. 10-12; 1956b: see entry, South America); Reischer (loc. cit.); Rose (1932:35, pl. 3, figs. 20-22); Wolf (1944:27, pl. 2, fig. 12); A. W. Ziegler (1948b:21, pl. 4, fig. 2; 1952:9, pl. 3, fig. 8). USSR: Milovtsova (1935a: 34, pl. 3, figs. H1, H2); Morochkovs’kiĭ et al. (1967:140, fig. 127); Naumov (1954:71, fig. 36); Shkorbatov (1927:77). RECORDED COLLECTIONS: -- AFRICA: Alabi (1971a, b; 1973); Nolard- Tintigner (1974). BELGIUM: Bommer and Rousseau (1884). BRITISH ISLES: Apinis (1960, 1964); Cook and Morgan (1934); Dick (1962, 1963, 1966); Dick and Newby (1961); Forbes (1935a, b); P. H. Gregory (1951); Hunter (1975); O’Sullivan (1965); Perrott (1960); R. E. Roberts (1963). CANADA: Dick (1971c). CZECHOSLOVAKIA: Cejp (1931, 1934). DENMARK: A. Lund (1978); Obel (1910b). FINLAND: Häyrén (1902-03, 1956). GERMANY: Bock (1956); Höhnk (1935a, 1956a, 1957a); Pieters (1915a); Rick (1903); Stoll (1936). HUNGARY: Moesz (1937-38). ICELAND: Howard et al. (1970). INDIA: Dayal and Thakur Ji (1965, 1973); Thakur Ji (1967). IRAQ: Al-Saadi et al. (1979). JAPAN: Hoshina et al. (1960); T. ITO (1944); S. Ito and Nagai (1931); Okane (1978); Ookubo (1954); Suzuki (1960a, d, f; 1961a, b, e, f, i); Suzuki and Hatakeyama (1961); Suzuki and Nimura (1960, 1961d); Suzuki and Tatsuno (1964, 1965b). LAPLAND: Gäumann (1918); LATVIA: Apinis (1929a). NETHERLANDS: Beverwijk (1948). RUMANIA: Toma (1969). UNITED STATES: Coker (1927); Coker and Braxton (1926); Crane and Vermillion (1966); J. V. Harvey (1925a, b, 1927c, 1930); G. L. Hoffman (1949); Höhnk (1933, 1935a); Kauffman (1915); Klich (1980); R. Martin (1968a); V. D. Matthews (1927); Monsma (1936); Poitras (1955); K. B. Raper (1928); Scott (1962); Slifkin (1964); Sparrow (1952b); TeStrake (1958); M. W. Ward (1939); A. W. Ziegler (1958b). USSR: Domashova (1974b); Dudka (1965, 1966); Érgashev and Kirgizbaeva (1978); Logvinenko and Meshcheryakova (1971); Mil'ko (1965); Mil'ko and Belyakova (1968); Mil'ko and Dudka (1968); Osipyan et al. (1974); Yachevskim' (1895). YUGOSLAVIA: Ristanović (1973). SPECIMENS EXAMINED: -- AFRICA (4), RLS. ICELAND (13), NORWAY (12), SWEDEN (2), UNITED STATES (4), TWJ, RLS. Centraalbureau (1).

503 Achlya apiculata de Bary Bot. Zeitung (Berlin) 46:635, pl. 10, figs. 3-5. 1888. (Figures 60 A-D; 62 H-I, 64 A)

Achlya apiculata var. prolifica Coker and Couch, in Coker, Saprolegniaceae, p. 127, pl. 43, figs. 2-7; pl. 50, fig. 5. 1923. Achlya brasiliensis Milanez, Rickia 2:184, p1s. 1, 2. 1965. Achlya curvicollis Beroqui, Kurtziana 5:96, fig. 1. 1969.

Monoecious. Mycelium extensive, diffuse, but sometimes dense at the colony periphery; hyphae slender or stout; moderately or sparingly branched. Sporangia usually sparse; fusiform, cylindrical or clavate; straight, curved, or bent; occasionally with an attenuated apex that may be irregular or sigmoid; renewed sympodially or in basipetalous succession; 140-700 x 15-57 µm. Spores monomorphic; discharge and behavior achlyoid, rarely aplanoid or dictyucoid; primary spore cysts 12-15 µm in diameter. Gemmae sparse or abundant; fusiform, cylindrical, clavate, globose, infrequently irregular or branched; terminal or intercalary, single or catenulate. Oogonia sparse or abundant; lateral, occasionally terminal or intercalary; frequently or occasionally apiculate, or spherical, subspherical, oval or obpyriform, rarely cylindrical (then in emptied sporangium); (50-) 60-80 (-140) x (40-) 50-60 (-110) µm. Oogonial wall unpitted, pitted only under region of antheridial cell attachment, very sparsely pitted elsewhere; smooth on outer surface, inner surface occasionally irregular. Oogonial 1 stalks ( /2-) 1-5 (-12) times the diameter of the oogonium, in length; stout; generally curved, bent, or sparingly coiled, usually irregular, rarely straight, unbranched, infrequently branched. Oospores occasionally not maturing; centric or subcentric; spherical or ellipsoidal; (1-) 4-14 (-28) per oogonium, and occasionally filling it; (20-) 25- 35 (-86) µm in diameter; at germination forming a short, unbranched germ hypha bearing a small, cylindrical, terminal sporangium, or germ hypha becoming sparingly branched. Antheridial branches predominantly monoclinous, occasionally androgynous, rarely or infrequently diclinous; long or short, slender, curved, or irregular; unbranched or sparingly branched; persisting. Antheridial cells simple; tubular or clavate, occasionally lobed or slightly irregular; persisting; generally laterally appressed, rarely attached apically or in an inconspicuous, digitate manner; fertilization tubes, when present, not persisting.

The specific name applied by de Bary to his species implies that the oogonia were predominantly apiculate, and certainly such occur (Fig. 64 A) in specimens in the de Bary collection deposited at the British Museum (Natural History). However, the frequency of apiculate oogonia in isolates we have seen is variable. Achlya apiculata can be identified confidently on the combination of long, often sparingly coiled oogonial stalks, the relatively large, centric or subcentric oospores, and at least the occasional presence of apiculate oogonia. Generally there are few oospores in the oogonia of A.

504 apiculata, and in some individuals the oospheres fail to mature or the oospores abort shortly after forming. The inclusion of Achlya apiculata var. prolifica (Coker, loc. cit.) with A. apiculata was justified adequately by T. W. Johnson (1956b:34 et sqq.). We consider A. brasiliensis (Milanez, loc. cit.) and A. curvicollis (Beroqui de Martinez, loc. cit.) to be conspecific with de Bary’s species, our decision being based on the following analysis. As Milanez (loc. cit.) described Achlya brasiliensis it was nearest A. orion in general appearance, but distinguishable from that species by reason of differences in (1) oogonium and oospore diameters, (2) frequency of antheridial branch origin types, and (3) the structure of the oospore. We agree with Milanez that his species was not identifiable with A. orion. Milanez pointed out in his discussion of A. brasiliensis that its large, centric oospores (that often did not mature), and the rarity of apiculate oogonia appeared to separate adequately his species from A. apiculata. In the specimens of A. apiculata that we have examined, both centric and subcentric oospores occur, although, to be sure, the latter predominate. Inasmuch as the frequency of apiculate oogonia may vary from individual to individual in A. apiculata, this particular structural feature is unreliable when used to separate A. brasiliensis from de Bary’s species. Both taxa have the three major types of antheridial branches (the description by Milanez does not refer to diclinous antheridia in A. brasiliensis, but the discussion states that such were present in the type material). Oospore size and predominant number vary among the cultures of A. apiculata at hand, and these characters, too, do not separate A. brasiliensis from de Bary’s species. The same may be said for the magnitude of oosphere maturation and the nature of wall pitting. Milanez (loc. cit.) reported that the oospores in A. brasiliensis did not fill the oogonium, but the illustrations he provided suggest that they may do so. This feature also is one shared with A. apiculata. Although A. brasiliensis appears to have predominantly longer oogonial stalks than A. apiculata (Milanez, loc. cit., pl. 1, fig. 1), we do not believe that this one characteristic is important enough taxonomically to justify maintaining two species. The description of Achlya curvicollis (Beroqui de Martinez, 1969) could be applied readily to common forms of A. apiculata, and the illustrations of the former convince us that it is synonymous with de Bary’s species. Achlya curvicollis has coiled, spiral, or curved oogonial stalks just as does A. apiculata and the size differences in oogonia and oospores are of such slight magnitude as to be unimportant taxonomically. Achlya curvicollis may have more abundant diclinous antheridial branches than A. apiculata, but this is in all probability attributable to strain differences as is the alleged sparseness of apiculate oogonia in Beroqui de Martinez’s species. The pattern of wall pitting in the oogonia of both taxa is essentially the same. The fungus that Beroqui de Martinez chose to name Achlya curvicollis clearly occupies a position somewhat intermediate between A. apiculata (sensu lato) and de Bary’s A. oblongata var. oblongata. Specimens of A. oblongata var. oblongata, however, have predominantly larger oogonia and generally more oospores per oogonium than A. apiculata. In addition, the antheridial filaments of the variety oblongata are only diclinous so far as is known, and of course, the variety lacks apiculate oogonia.

505 Milanez (1970) found in Brazil a variant of Achlya apiculata with a greater number of predominantly smaller (21-24 µm) oospores than is usually encountered in this taxon. De Bary did not report any oospore size for his specimens, but those in his preserved material of A. apiculata (British Museum, Natural History) are 28-36 µm in diameter. According to T. W. Johnson (1956b) the oospores of this species are 35-40 µm. Oospores in the Brazilian plants of A. apiculata were type II (a lunate cluster of refractive droplets) although an earlier description had characterized them as Type I (T. W. Johnson, 1956b: pl. 1). In some of the specimens we have examined, both types occur. Milanez (1970: fig. 31) also found in his collection of A. apiculata long-stalked oogonia, inconspicuously pitted oogonia, and oospore abortion. We suggest that the Brazilian form further strengthens our decision to merge A. brasiliensis and A. apiculata. Variants of Achlya apiculata have been described from time to time, and misidentifications or doubtful determinations have appeared as published records of the species. Very few oospores were produced in the oogonia of specimens reported by Forbes (1935a). Cejp (19590: 172) described Forbes’ (1935a: 232) specimen of A. apiculata var. prolifica under a new (but illegitimate) name, A. apiculata var. forbesiana. As the fungus identified by Forbes differed hardly at all from the variety prolifica -- and the latter is only a variant of de Bary’s species -- Cejp’s naming cannot stand (even if it had been validly published). The Philippine record of a watermold described by Graff (1918) as Achlya apiculata is suspect. Graff reported that it was necessary to contaminate pure cultures of his isolates with bacteria before sexual reproduction could occur. Dogma (1966) likewise questioned Graff’s account, noting that the addition of contaminants to cultures might have inadvertently introduced spores of another watermold that did reproduce sexually, and Graff therefore concluded wrongly that A. apiculata was the species at hand (there are no descriptive notes or illustrations in Graff’s report). Teodoro (1937:34, 35) quoted freely from Graff’s paper in listing A. apiculata among the fungi known from the Philippines. The record by Cejp (1934:190, pl. 1, figs. 11, 12) of A. apiculata from the province of Bohemia must be discarded. He saw only sporangia and gemmae in the specimens and in any case seems to have been dealing with a mixed culture (an Achlya, a Dictyuchus, and Pythiogeton transversum Minden). In the distribution records assembled by T. W. Johnson (1956b: 34), Earle (1901) is cited as reporting Achlya apiculata from Alabama, but it was Mohr (1901) who listed the species and attributed its discovery to Atkinson. The A. apiculata used by J. N. Couch (1924a) in his study on spore discharge was not an original collection with him.

CONFIRMED RECORDS: -- AUSTRALIA: Cookson (1937:240). BRITISH ISLES: Forbes (1935a:232), H. M. Ward (1883: pl. 22, figs. 15, 16). CANADA: C. L. Moore (1908- 09:227, figs. 10-13). CZECHOSLOVAKIA: Cejp (1959a:170, figs. 54, 55). GERMANY: deBary (loc. cit.); A. Fischer (1892:351); Richter (1937:250). ICELAND: Howard et al. (1970:68, fig. 17). INDIA: Dayal and Thakur Ji (1968b:237, figs. 1-7); Khulbe (1980); Thakur Ji (1967). JAPAN: Okane (1977:4, figs. I-K). LATVIA: Apinis (1929a:230, pl. 4, figs. 4, 5). MIDDLE EUROPE: Migula (1903:69). REPUBLIC OF CHINA: Chiou et al.

506 (1975:164, pl. 2, figs. 17, 18). SOUTH AMERICA: Milanez (loc. cit.; 1970:25, figs. 29-35). UNITED STATES: R. L. Butler (1975: figs. 81-84); Coker (1923:123, p1s. 42, 43, fig. 1; loc. cit.); Humphrey (1893:120, pl. 14, figs. 5, 12; pl. 15, figs. 22, 26, 27; pl. 19, figs. 82-86); T. W. Johnson (1956b:33, pl. 4 figs. A, B; pl. 5, figs. K-O); A. W. Ziegler (1948b:25, pl. 5, fig. 5; 1952:10, pl. 4, figs. 8,9). RECORDED COLLECTIONS: -- BRITISH ISLES: Apinis (1964); Cook and Morgan (1934); Cook and Forbes (1933); Dick (1962, 1963, 1966); Dick and Newby (1961); Forbes (1935b); Hartog (1895); O’Sullivan (1965); Perrott (1960); Ramsbottom (1915a); R. E. Roberts (1963); Willoughby (1974). CANADA: Dick (1971c). GERMANY: Höhnk (1935a). INDIA: Khulbe (1977, 1980a); Khulbe and Bhargava (1977). JAPAN: Okane (1978); Ookubo (1954: 49, fig. 38; possibly A. americana; Suzuki (1961f). SOUTH AMERICA: Upadhyay (1967). UNITED STATES: Atkinson (1897); Barksdale (1960); Coker (1927); T. W. Johnson (1956a); V. D. Matthews (1927); J. R. Raper (1950b); M. W. Ward (1939); A. W. Ziegler (1958b). USSR: Logvinenko (1971); Logvinenko and Meshcheryakova (1971). SPECIMENS EXAMINED: -- Preserved specimens, unnumbered, de Bary collection, British Museum (Natural History). Type, Coker and Couch, var. prolifica. ICELAND (1), UNITED STATES (4), TWJ, RLS. SOUTH AMERICA (3), RLS. MWD (2).

Achlya androgyna (Archer) Johnson and Seymour Mycotaxon 92:11-32, figs. 6-13. 2005, and present figs. 66 A-D, 84 J-M

Saprolegnia androgyna Archer, Quart. J. Microscop. Sci. (N.S.) 7:123, pl. 6, fig. 1. 1867. Basionym Achlya braunii Reinsch, Jahrb. Wiss. Bot. 11:284, pl. 14, figs. 1-6. 1878. Aplanes braunii de Bary, Bot. Zeitung (Berlin) 46:650, pl. 9, fig. 2. 1888. Saprolegnia treleaseana Humphrey, Trans. Amer. Phil. Soc. (N.S.) 17:111, pl. 17, figs. 56- 59. 1893. Aplanes androgynus (Archer) Humphrey, Trans. Amer. Phil. Soc. (N.S.) 17:134. 1893. Achlya treleaseana (Humphrey) Kauffman, 8th Rep. Michigan Acad. Sci., Arts, Ltrs. 8:27. 1906. Achlya acadiensis Moore, Proc. & Trans. Nova Scotian Inst. Sci. 12:229, figs. 16-19. 1908- 09. Aplanes braunii var. mindenii Shkorbatov, Bot. Mater. Inst. Sporov. Rast. Glavn. Bot. Sada RSFSR 2:36. 1923. Aplanes treleaseanus (Humphrey) Coker, J. Elisha Mitchell Sci. Soc. 42:217, p1s. 34, 35. 1927. [non Aplanes treleaseanus (Humphrey) Coker, Saprolegniaceae, p. 79, pl. 20. 1923.] Aplanes treleaseanus (Humphrey) Naumova, Bot. Mater. Otd. Sporov. Rast. Bot. Inst. Akad. Nauk SSSR 10:135, fig. 3. 1955. Aplanes androgynus var. mindenii (Shkorbatov) Cejp, Oomycetes I, Flora ČSR, Ser. B, Part 2, p. 271. 1959.

507 Monoecious. Mycelium compact and limited in extent, or diffuse and extensive. Sporangia extremely rare, but formed in special culture conditions; when present, naviculate, fusiform, clavate, or cylindrical; renewed sympodially; 77-988 x 12-42 µm. Spores monomorphic; discharge and behavior achlyoid or aplanoid, very rarely dictyucoid; spore cluster not persisting at exit orifice; primary spore cysts 10-14 µm in diameter. Gemmae very abundant; fusiform, naviculate, cylindrical, or irregular; occasionally pyriform or obpyriform; branched or unbranched; terminal or intercalary, single or catenulate. Oogonia terminal, intercalary, or lateral; single or catenulate when intercalary; predominantly dolioform, fusiform, or naviculate, occasionally spherical, obpyriform, or cylindrical, rarely irregular or asymmetrical; elongate ones (50-) 105-200 (-508) x (25-) 5l-80 (-99) µm, exclusive of wall ornamentations (when present); spherical ones (25-) 70-85(-94) µm in diameter, exclusive of wall ornamentations (when present). Oogonial wall pitted; smooth, or densely or sparsely provided with papillate projections; rarely tuberculate, or with one or a few conical spines. Oogonial stalks ½-4 times the diameter of the oogonium, in length; straight or curved; isodiametric or slightly irregular in outline; unbranched. Oospores usually subcentric, rarely centric; generally spherical, sometimes angular when crowded; (1-) 8-20 (-40) per oogonium, and usually filling it; (l6-) 24-30 (-44) µm in diameter; on germination forming a branched hyphal system, or producing a slender, unbranched hypha bearing a small, terminal, fusiform sporangium discharging in an achlyoid, dictyucoid, or aplanoid fashion. Antheridial branches predominantly monoclinous or androgynous, rarely diclinous; sparingly branched or unbranched; usually short, somewhat irregular in outline, persisting. Antheridial cells simple, rarely compound; persisting; unbranched or once-branched; tubular or clavate; generally digitate, very rarely laterally appressed; fertilization tubes usually absent.

In his 1956(b) monograph, T. W. Johnson treated as Achlya treleaseana a taxon previously assigned to Aplanes. A nearly identical species -- except for the absence of oogonial wall ornamentations -- is Reinsch’s (loc. cit.) Achlya braunii; Johnson excluded this taxon from Achlya because it was alleged to be a member of Aplanes. A third species, remarkably similar to A. treleaseana and A. braunii, is Saprolegnia androgyna Archer (loc. cit.), which Humphrey (loc. cit.) had assigned to de Bary’s (1888: 613) genus Aplanes. The three species -- androgyna, treleaseana, and braunii (irrespective of their supposed generic affinity) -- share certain prominent morphological features. Foremost among these is a noticeable rarity of sporangia, but when such structures are produced the primary spores (certainly those in the latter two taxa) behave in an achlyoid or aplanoid manner. Cultures of treleaseana and braunii form achlyoid sporangia in acid water; it is not known whether Archer’s Saprolegnia androgyna responded similarly. All three taxa are identical in their production of fusiform or dolioform, intercalary, pitted oogonia that are usually provided with subtending monoclinous antheridial branches (sensu T. W. Johnson, 1956b: pl. 1, fig. 8i) and a few to many subcentric oospores (Fig. 84

508 J, M; 66 A, B). Additionally, representatives of these three species produce some lateral, spherical oogonia (Fig. 84 K). The one seemingly consequential difference among androgyna, braunii, and treleaseana, as they have become circumscribed through the years since their discovery, is the nature of the oogonial wall. In treleaseana the oogonia generally are papillate, but in the other taxa these cells are smooth. However, there are prominent descriptions that report the presence of smooth oogonia in treleaseana, and ornamented ones in braunii. That the systematics of the three species with dolioform or fusiform, intercalary oogonia long has been unsettled chiefly is because of two problems. The first has its roots in de Bary’s own account of Aplanes. Although this genus was described formally in 1888, de Bary mentioned it in 1884, and wrote that specimens of it probably were identical with Reinsch’s Achlya braunii. As to the characteristic on which Aplanes was established -- the pattern of primary spore behavior -- de Bary (1888:613) simply said that the spores of the species were not motile, but otherwise the characteristics were like those in representatives of Achlya. Reinsch (loc. cit.) illustrated an empty sporangium and a dictyucoid one for the fungus he described as Achlya braunii. In describing Achlya acadiensis as a provisional new species, C. L. Moore (1908-09:232) induced his fungus (identical to Achlya treleaseana in sex apparatus configuration), to produce achlyoid sporangia on colonies growing in water containing living plants of Sphagnum sp. Colonies of the fungus in water without Sphagnum developed sporangia whose spores germinated in situ (that is, were aplanoid sensu de Bary). Shkorbatov (1927:83) did not illustrate his variety mindenii of Aplanes braunii, but stated that the sporangia discharged as in Achlya, Dictyuchus, or Aplanes. Following Humphrey’s (loc. cit.) decision to assign Archer’s Saprolegnia androgyna to Aplanes, Cejp (1959a:268) simply reduced Shkorbatov’s taxon to varietal status under Aplanes androgynus. Archer (loc. cit.) did not see sporangia in the watermold he named Saprolegnia androgyna - not surprising in view of their rarity. The evidence on the point of the type of spore discharge is clear: these various taxa with similar sex cell morphologies produce some achlyoid sporangia. The second problem in the taxonomy of the three taxa braunii, treleaseana, and androgyna is that of the nature of the oogonial wall. Some reports -- for example, Migula (1903:75) -- do not mention any structural of the oogonium wall. In other accounts, however, the oogonia are described as papillate or smooth (T. W. Johnson, 1956b). Reinsch’s illustrations of Achlya braunii show smooth oogonia, except for one figure (Reinsch, 1878: pl. 14, fig. 6) that depicts a papillate immature oogonium. The most convincing evidence that Reinsch’s species and de Bary’s Aplanes braunii are the same taxon comes from preserved specimens of the latter, deposited in the British Museum (Natural History). In that material (labeled by de Bary as Aplanes braunii) there are smooth, papillate (Fig. 66 C), and irregular (Fig. 66 D) oogonia. Thus, de Bary’s braunii combined characters both of Reinsch’s braunii and Humphrey’s treleaseana (variously assigned to Achlya, Aplanes, or Saprolegnia). Moreover, some oogonia in de Bary’s material of Aplanes braunii are identical to those described by Archer for “Saprolegnia” (Achlya) androgyna. Reinsch’s Achlya braunii does not differ at all from Archer’s species.

509 Is there experimental evidence to support our contention that the presence or absence of wall ornamentations is variable and therefore not taxonomically significant? We have manipulated the culture conditions (temperature, pH, and source of water) in attempts to modify the wall configuration of isolates with smooth oogonia (androgyna- braunii), and those with ornamented ones (treleaseana). Incubation temperatures of 8 o, 10 o, and 15 oC induced colonies of the treleaseana type to produce oogonia with smaller and fewer ornamentations than those developed by control specimens propagated at 25-28 oC. The numbers of smooth oogonia developed by colonies at the low temperatures was greater (41%) than in the controls (8%). With one exception, neither temperature nor source of water (distilled, pond, stream, or soil extract -- unbuffered, pH 4.3, 6.8, 8.1 respectively) -- induced isolates of the androgyna-braunii type to form papillate oogonia. At 10 oC some colonies propagated in acidified, autoclaved, soil extract produced sparsely crenulate oogonia. The scanty experimental evidence at hand thus is indicative, but is not conclusive that ornamentation may be environmentally modified. In this complex of three taxa there is a situation precisely parallel to that in the Saprolegnia ferax-S. mixta group (Seymour, 1970) and the Aphanomyces laevis-A. helicoides galaxy (see Aphanomyces). Some isolates align at once with treleaseana (ornamented oogonia), and others with androgyna-braunii (smooth oogonia). There are, as well, intermediate forms with respect to oogonial wall configuration, particularly in the treleaseana sector where it is common for oogonia in some specimens to be very sparsely ornamented. We are removing Achlya braunii and Saprolegnia androgyna from the excluded taxon category (T. W. Johnson, 1956b), and recognizing the former as a synonym of the latter (which is itself raised to valid status in the genus Achlya). Cejp (1959a:268) was correct in considering Shkorbatov’s Aplanes braunii var. mindenii as a synonym of Aplanes androgynus (Archer) Humphrey. Apparently unaware of Coker’s (1927) Aplanes treleaseanus (Humphrey), Naumova (loc. cit.) published precisely the same (and thus redundant) name change. We have examined over 60 collections representing Achlya treleaseana (Humphrey) Kauffman and Achlya (Aplanes) braunii (=Saprolegnia androgyna). None of the specimens had the peculiar Type III subcentric oospores which T. W. Johnson (1956b) described for an isolate identified as A. treleaseana. That particular oospore structure was probably an aberration, as Johnson surmised; in any case, the form has no taxonomic status. The true identity of an unusual form of Achlya treleaseana reported from Iceland by Howard et al. (1970:68) remains unresolved. The single isolate had the oogonial configuration of A. treleaseana (=A. androgyna), but lacked antheridial branches, and pitted oogonia. In its general features, the isolate was strikingly like Harz’s (1906) A. hoferi (no antheridial apparatus, but intercalary, dolioform oogonia). Achlya hoferi -- doubtfully valid according to T. W. Johnson (1956b) -- presumably produced sporangia regularly, which, of course, “A. treleaseana” does not do.

510 It seems all too likely, as Howard and his associates (1970) suspected, that Raciborski’s (1886) Achlya nowickii was the same species as the one subsequently described by Humphrey (1893) under the epithet treleaseana. The single oogonium figured by Raciborski (1886: pl. 3) is a terminal, dolioform, papillate cell, without antheridial branches, but containing more than 10 oospores. The sporangia of A. nowickii are illustrated in achlyoid and aplanoid discharge configurations. The resemblance of the illustrated oogonium of A. nowickii to those depicted for A. androgyna is undeniable. We suspect that Raciborski’s fungus was A. androgyna, but as the circumscription provided is extremely vague the matter cannot now be settled with finality. The Aplanes treleaseanus, treated as a new combination by Coker in his monograph of 1923, was Saprolegnia turfosa. Cejp’s (1931) report of this species from Czechoslovakia was based on Coker’s misidentification, and the same may be said for Richter’s (1937:259, fig. 17) report of A. treleaseanus. Figure 7c of A. Lund’s (1934:20) paper on some Danish watermolds depicts S. turfosa, not Aplanes treleaseanus. Curiously, A. Lund (1934: 21) regarded the names Saprolegnia treleaseana Humphrey and Achlya treleaseana (Humphrey) Kauffman as synonyms of Coker’s (1923) misidentified Aplanes treleaseanus. Other investigators may have perpetuated Coker’s error. Ramsbottom recognized Aplanes braunii deBary in his first publication in 1915(a), but later the same year (1915b) relegated de Bary’s species to synonymy with Aplanes androgynus (Archer) Humphrey. As Ramsbottom’s listing of species (1915a) is not accompanied by citations to sources or localities, it does not constitute a record of the individual taxa.

CONFIRMED RECORDS: -- AFRICA: Alabi (1967: pl. 11, figs. a, b); EI-Hissy (1974: pl. 1, fig. a). BRITISH ISLES: Archer (loc. cit.); R. A. Couch (1951:98, pl. 16). CANADA: C. L. Moore (loc. cit.). CZECHOSLOVAKIA: Cejp (1959a:268, 271, figs. 102, 103). DENMARK: Petersen (1909a:387). GERMANY: de Bary (loc. cit.); Minden (1912:573, fig. 8); Reinsch (loc. cit.); Richter (1937:258, fig. 16). GREENLAND: Kobayasi et al. (1971:20, text fig. 9). ICELAND: Howard et al. (1970:68, fig. 22). JAPAN: Kobayasi and Ookubo (1952b:181, fig. 8). MIDDLE EUROPE: Migula (1903:75, pl. 2c, fig. 2). POLAND: Szwanke (1938:14, pl. 5, fig. 8): Zaborowska (1965:48, fig. 10). SOUTH AMERICA: Upadhyay (1967:57). UNITED STATES: R. L. Butler (1975: figs. 133-136; 153-156); Coker (loc. cit.); Humphrey (loc. cit.); Kauffman (loc. cit.); V. D. Matthews (1935:308); Milanez (1966:87, pl. 7, figs. a-c); A. W. Ziegler (1952:11, pl. 5, figs. 2,3). USSR: Morochkovs'kiĭ et al. (1967:122, fig. 105); Naumov (1954:63, fig. 31); Naumova (loc. cit.); Shkorbatov (loc. cit.; 1927:79, 83). RECORDED COLLECTIONS: -- AFRICA: Alabi (1971a, b; 1973). BRITISH ISLES: Dick (1963); Dick and Newby (1961); R. E. Roberts (1963). CANADA: Dick (1971c). CZECHOSLOVAKIA: Cejp (1931, 1934). DENMARK: A. Lund (1934); Petersen (1910). IRAQ: Al-Saadi et al. (1979). JAPAN: Kobayashi and Ôkubo (1954); Ôkubo (1954); Suzuki (1961f); Suzuki and Hatakeyama (1960); Suzuki and Nimura (1960). LATVIA: Apinis (1929a: 227; questionable -- does not describe antheridial apparatus). NEW

511 ZEALAND: Karling (1966f). UNITED STATES: Barksdale (1960); G. C. Hughes (1959, 1962); C. E. Miller (1965); Paterson (1967); Scott et al. (1963); Sparrow (1952b); A. W. Ziegler (1958b). USSR: Logvinenko and Meshcheryakova (1971); Mil’ko and Belyakova (1968). SPECIMENS EXAMINED: -- ICELAND (2), NORWAY (6), SWEDEN (55), UNITED STATES (17), TWJ, RLS. Centraalbureau (1), MWD (2).

Achlya ornata Johnson and Seymour Mycotaxon 92:11-32, figs. 18-25. 2005, and present fig. 80 A-H

Aplanopsis spinosa Dick, Trans. Brit. Mycol. Soc. 43:60, pl. 2; text figs. 1, 2. 1960. Basionym

Monoecious. Mycelium extensive; hyphae slender, flaccid, slightly irregular and sinuous, and frequently branched, often sympodially from below hyphal tips. Sporangia extremely rarely produced, then very sparse, appearing on early formed hyphae, and then quickly evanescent; cylindro-fusiform or cylindrical; method of renewal not known; 100-135 x 20-25 µm. Spores monomorphic; discharge and behavior achlyoid; exit pore terminal or lateral; spore cluster falling away readily from exit orifice; primary spore cysts 10-12 µm in diameter. Gemmae lacking. Oogonia lateral, occasionally intercalary and single or catenulate, rarely terminal; spherical or subspherical, broadly ellipsoidal or dolioform when intercalary; infrequently ovoid or with an elongate, tubular apiculus; (l7-) 30-40 (-67) µm in diameter, including wall ornamentations. Oogonial wall densely ornamented with apically rounded or mammiform papillae, truncate or conical cylindrical projections that are straight, curved, or faintly hamate; wall extensions sometimes lobed or inconspicuously indented; thin, unpitted. Oogonial stalks (2-) 3-4 (-9) times the diameter of the oogonium, in length; slender, flaccid, slightly twisted or irregular; unbranched or rarely once-branched; often arranged in a racemose manner on the slender principal hyphae. Oospores subcentric; spherical, oval or ellipsoidal; 1 (-4) per oogonium and usually filling it; (10-) 16-24 (-42) µm in diameter; at germination forming a slender, sinuous, branched or unbranched germ hypha. Antheridial branches, when present, androgynous, or antheridial apparatus hemihypogynous; short, slender, irregular; persisting. Antheridial cells simple; clavate or irregularly bulbous; persisting; apically appressed; fertilization tubes present but obscured by wall ornamentations, apparently persisting.

Ordinarily, it is not possible to distinguish among species of watermolds by the macroscopic appearance of the colony in water. Achlya ornata is one of few exceptions: its mycelium is very diffuse, quite extensive (4-6 cm in diameter), and conspicuously flaccid. Achlya ornata is not difficult to distinguish from other Achlyas with ornamented oogonia and subcentric (or centric) oospores. The oogonia of A. ornata are more densely

512 ornamented (Fig. 80 A) than those commonly found in A. stellata (Fig. 65 A-D). Moreover, the wall projections in de Bary’s species are short and broadly papillate (Fig. 65 F, G) rather than narrowly papillate or elongate and curved or bent (Fig. 80 F-H), as in A. ornata. Achlya stellata has no antheridia, whereas A. ornata does. The oogonial wall ornamentations in Achlya spinosa may be as frequent as those of A. ornata, but they are coarser (Fig. 65 N-P). Achlya radiosa has predominantly a short-mammiform type of wall projection, but this is not a configuration found in A. ornata. Both A. colorata and A. papillosa have papillate oogonia, but the oogonia are much larger than those of A. ornata, and consistently contain several oospores rather than a single one. There is a distinctive arrangement to the lateral oogonia of Achlya ornata (seen and recorded by Dick, loc. cit., in his account of Aplanopsis spinosa). The species often produces numerous lateral branches (some bearing oogonia) in a racemose fashion in regions along the hyphae (Fig. 80 A). This branching pattern confers on the mycelium a pattern suggesting a whorled cluster of hyphae. Dick (loc. cit.) assigned his species to Aplanopsis because he apparently did not observe sporangia. However, one of the isolates obtained from Dick forms sporangia -- they are very scanty and quickly evanescent -- with an achlyoid discharge pattern, and for this reason the species must be placed in Achlya. As the epithet spinosa is preempted by one of de Bary’s (1881) species, we are providing the new name, ornata, in reference to the dense, variously-shaped oogonial wall projections.

CONFIRMED RECORDS: -- BRITISH ISLES: Dick (loc. cit.); O’Sullivan (1965: figs. 15-17). RECORDED COLLECTIONS: -- BRITISH ISLES: Dick (1962, 1963, 1966); Thornton (1970); Willoughby (1965, 1974). DENMARK: A. Lund (1978). SPECIMENS EXAMINED: -- NORWAY (3), TWJ. MWD (2)

Achlya dubia Coker Saprolegniaceae, p. 135, pl. 49. 1923 (Figure 67A-E)

Monoecious. Mycelium limited, dense; hyphae stout, sparingly to moderately branched. Sporangia fusiform, cylindrical, clavate, or naviculate, occasionally provided with a lateral exit tube; renewed sympodially or in a basipetalous manner; 60-380 x 8-45 µm. Spores monomorphic; discharge and behavior thraustothecoid or achlyoid from primary sporangia, achlyoid or rarely dictyucoid or aplanoid from secondary ones; thraustothecoid behavior not persisting as isolates age or are subcultured; primary spore cysts 9-14 µm in diameter; infrequently some sporangia contain large, broadly ellipsoidal or bacilliform, spore-like segments. Gemmae sparse or abundant; cylindrical, irregular, occasionally branched, or spherical; terminal or intercalary, single or catenulate, and when the latter, often disarticulating. Oogonia lateral, rarely or only infrequently terminal; spherical or obpyriform, rarely subglobose or faintly irregular;

513 initials freely or only occasionally proliferating; (22-) 40-60 (-97) µm in diameter. Oogonial wall pitted under the region of antheridial cell attachment, or occasionally 1 1 elsewhere as well; smooth. Oogonial stalks ( /4-) 1 /2 – 2 (-4) times the diameter of the oogonium, in length; straight, curved, or slightly irregular; infrequently branched. Oospores eccentric, but often maturing slowly, and only rarely aborting; spherical or ellipsoidal; (1-) 3-6 (-18) per oogonium, and filling it or not; (16-) 20-28 (-38) µm in diameter; germination not observed. Antheridial branches diclinous, very infrequently monoclinous; slender, long or short, unbranched or sparingly branched; sometimes partially clasping the oogonium to which attached; persisting. Antheridial cells simple; tubular, clavate, or irregular; persisting; attached in a digitate fashion, rarely laterally appressed; fertilization tubes present or not, but apparently persisting when formed.

We are not convinced that this species should be retained in Achlya, but as we had only a limited number of specimens on which to base a characterization, no other recourse is open to us. The difficulty encountered in trying to place A. dubia properly centers on its tendency to produce some thraustothecoid primary sporangia (Fig. 67 C, E). Indeed in some isolates the majority of primary sporangia may be thraustothecoid -- or so we judge from the literature. Coker (1923:139) summarized only the nature of A. dubia, stating that it was “...exactly intermediate between Achlya and Thraustotheca, or rather it combines... the characters of both.” Coker and Couch (1923:113), writing on Thraustotheca (=Calyptralegnia) achlyoides, commented that the discovery of A. dubia had “...broken down any sharp distinction between Achlya and Thraustotheca...” Our persistence in retaining Coker’s species in Achlya is patently contradictory to our belief that the nature of the primary (first-formed) sporangia must weigh heavily in assigning species to genera in the Saprolegniaceae. However, in two isolates of A. dubia from Puerto Rico the thraustothecoid sporangia do not persist. As the mycelium ages, the frequency of thraustothecoid sporangia decreases perceptibly, and, in fact, these cells have been eliminated by repeated sub-culturing from one of our isolates although the specimen was well-marked initially by its abundance of a thraustothecoid discharge pattern. Coker (1923) also had found that thraustothecoid sporangia dwindled in frequency as he subcultured his two specimens of the species. Some observations by Alabi (1972: fig. 1A, B) and Murdia (1939a) on Achlya dubia are relevant. Those individuals of A. dubia which Alabi recovered from Nigerian soils during the rainy season produced sporangia of the achlyoid type predominantly. Specimens collected during the dry seasons had only primary sporangia of the achlyoid type; the secondary ones released spores after the manner of Thraustotheca species. By experimental means Alabi demonstrated that at incubation temperatures of 10-25 oC A. dubia cultures produced more achlyoid than thraustothecoid sporangia. At 28 o, 30 o, and 32 oC, on the contrary, the mycelium formed a greater proportion of thraustothecoid than achlyoid ones. Murdia (1939a) concluded that in well-aerated water, the sporangia of A. dubia were achlyoid as to spore release, but in poorly aerated conditions, the pattern was dictyucoid or aplanoid (he refers to both types as the “Dictyuchus state”).

514 We have transferred Thraustotheca irregularis to Achlya even though that species produces thraustothecoid sporangia. Unlike A. dubia, however, T. irregularis consistently has achlyoid primary sporangia and the thraustothecoid ones are only secondarily produced. Not all investigators subsequent to Coker reported thraustothecoid sporangia in the specimens they identified as Achlya dubia -- Chandhuri and Kochhar (1935), Chaudhuri et al. (1947), Richter (1937), and Schlösser (1929). Such records are suspect. Achlya dubia var. pigmenta Chaudhuri and Kochhar possibly was a specimen of A. debaryana. Their variety is too sketchily defined to retain among the valid taxa. In the absence of any thraustothecoid sporangia, Achlya dubia would be identifiable as A. debaryana. That Coker’s species is a hybrid between a debaryana-like Achlya and a Thraustotheca cannot be ruled out, but is yet to be proven. Extensive comparative analyses of the characteristics of many different isolates of Achlya dubia are needed before its position can be settled with finality. Perhaps Sorenson’s (1962: 44) comments on the relationship between A. dubia and T. primoachlya (=A. primoachlya) are more than speculation. He suggested that A. dubia and T. primoachlya were intermediates between Achlya and Thraustotheca, with both species possibly having evolved from an ancestor also intermediate in form. Alternatively, he proposed, one of the two species may have descended from an ancestor resembling the other species.

CONFIRMED RECORDS: -- AFRICA: Alabi (1967:81, pl. 10, figs. a-c; 1972: fig. 1A, B); Goldsmith (1948:139, pl. 15, figs. 6, 7; pl. 16, fig. 8). BRITISH ISLES: R. A. Couch (1951:59, pls. 1-3). INDIA: Dayal and Thakur Ji (1969: figs. 12-16); Murdia (1938: pl. 12, figs. 3-8); S. B. Saksena and Rajagopalan (1958:14, figs. 35-40); G. C. Srivastava (1967a:285, pl. 2, figs. 5-7). IRAQ: Muhsin (1977:66, figs. A-C). JAPAN: Kobayasi and Konno (1971a:9, fig. 3C-E). REPUBLIC OF CHINA: Chiou et al. (1975:160, pl. 1, fig. 5). SOUTH AMERICA: Beneke and Rogers (1962:186); Hutchison (1940:16, fig. 10). UNITED STATES: R. L. Butler (1975: figs. 101-104); Coker (loc. cit.); Coker and Couch (1924: pl. 38, figs. 9-11); Holland (1958:18); T. W. Johnson (1956b:56, pl. 10, figs. A-C); Rossy-Valderrama (1955:31, pl. 5, figs. 1-3; 1956: 136); A. W. Ziegler (1952:9, pl. 3, figs. 3, 4). USSR: Naumov (1954: 72). RECORDED COLLECTIONS: -- AFRICA: Alabi (1971a, b; 1973); Fajola et al. (1979). BRITISH ISLES: Thornton (1970). GERMANY: Richter (1937: 252)(?); Schlösser (1929) INDIA: Bhargava et al. (1971); Chaudhuri and Kochhar (1935: 146, 147, pl. 10, figs. 9-14; pl. 11, figs. 1-12) (?); Chaudhuri et al. (1947: 38, fig. 15) (?); R. K. Saksena and Bose (1944); G. C. Srivastava (1967b); G. C. Srivastava and R. C. Srivastava (1977e); R. C. Srivastava (1976); R. C. Srivastava and G. C. Srivastava (1978a). UNITED STATES: Beneke and Schmitt (1961); W. B. Cooke and Bartsch (1959, 1960); G. C. Hughes (1959, 1962); Scott (1960b); Slifkin (1964); TeStrake (1958); A. W. Ziegler (1958b). USSR: Logvinenko (1971). SPECIMENS EXAMINED: -- AFRICA (7), RLS. UNITED STATES (2), C. Rossy- Valderrama. UNITED STATES (9), RLS.

515

Achlya diffusa Harvey ex Johnson Genus Achlya, p. 64, pl. 13. 1956. (Figure 68 F-J)

Achlya diffusa Harvey, J. Elisha Mitchell Sci. Soc. 58:29, pl. 6, figs. 4-8. 1942.

Monoecious. Mycelium moderately extensive; hyphae slender, sparingly branched; spherical or subglobose, laterally attached, unpitted, oogonium-like swellings produced sparingly or abundantly intermingled with oogonia on the hyphae, contents not cleaving into oospheres, 39-485 µm in diameter. Sporangia cylindrical or clavate; straight, slightly curved or irregular; renewed sympodially, occasionally cymosely or in a basipetalous succession; 105-980 x 11-57 µm in diameter. Spores monomorphic; discharge and behavior achlyoid, occasionally aplanoid; primary spore cysts, 9-14 µm in diameter. Gemmae sparse or abundant; cylindrical, irregular, or branched; terminal or intercalary, single or catenulate. Oogonia lateral, occasionally intercalary, rarely terminal or sessile; spherical, obovate, or obpyriform, occasionally broadly dolioform; (28-) 45-90 (-153) µm in diameter. Oogonial wall pitted, unpitted, or pitted only under the region of attachment of the antheridial cells; pits in larger oogonia occasionally as wide as the attached portion of the antheridial cell; smooth, or only rarely with one or 1 two prominent or inconspicuous, lateral projections. Oogonial stalks ( /4-) 2 (-4) times the diameter of the oogonium, in length; stout; straight, curved, twisted, or irregular; unbranched. Oospores maturing then often quickly aborting, or failing to mature; eccentric; spherical; (1-) 3-14 (-36) per oogonium, and rarely filling it; (l2-) 20-26 (-38) µm in diameter, at germination forming a slender, unbranched germ hypha bearing a small, terminal, achlyoid sporangium, or branched and producing new mycelium directly. Antheridial branches usually abundant; diclinous, rarely monoclinous; slender, irregular, twisted; unbranched or sparingly branched; infrequently a branch terminates in a small, spherical, functional oogonium; persisting. Antheridial cells simple; tubular to irregular; persisting; attached in a digitate fashion; fertilization tubes rarely observed, and evidently not persisting.

The inflated, unpitted, balloon-like, hyphal swellings (Fig. 68 F) intermingled with the oogonia - but only functioning in this capacity after a few weeks of incubation - constitute the most prominent structural feature of Achlya diffusa. In other respects A. diffusa is a cognate species to forms of A. debaryana. Isolates of Achlya diffusa are by no means constant with respect to oosphere maturation or longevity. The oogonia of some forms almost always produce oospores that persist or abort in varying numbers. In other strains, however, few oospores are found, indicating a tendency of the oospheres to fail to mature. Aborted oospores, of course, retain the thick-walled condition.

516 Inflated hyphal swellings are produced consistently by a watermold we suggest may be a hybrid (see Thraustotheca). The diffuse cytoplasm in the enlarged swellings produced by the alleged hybrid often cleaves readily into one or more oospores. The Achlya sp. 1 described by Kobayasi and Konno (1971b:382, fig. 4 H-J) may or may not be A. diffusa. The single representative of this unnamed watermold had abundant hyphal swellings (they were not illustrated) but evidently only formed monoclinous antheridial branches. The mature oospore type was not described. To some extent Achlya sp. 1 seems near A. debaryana, but the hyphal swellings ally it to A. diffusa. The position of Achlya sp. 1 in the genus remains obscure.

CONFIRMED RECORDS: -- CZECHOSLOVAKIA: Cejp (1959a:139, fig. 40). ICELAND: Howard et al. (1970:69). INDIA: Dayal and Thakur Ji (1968c:32, figs. 1-4); Prabhuji (1979:70, pl. 7, fig. 4); J. N. Rai and Misra (1977b:73, fig. la); G. C. Srivastava (1967a:286, pl. 3, fig. 1). SOUTH AMERICA: Beroqui de Martinez (1970:115, figs. 2 G-K, 3 M, N). UNITED STATES: R. L. Butler (1975: figs. 109-112); J. N. Harvey (loc. cit.); T. W. Johnson (1956b:64, pl. 13); Overman (1970:20); Rossy-Valderrama (1955:33, pl. 5, figs. 4,5; pl. 6, figs. 21-29); Sorenson (1962: pl. 2, figs. D, E; pl. 3, fig. C). RECORDED COLLECTIONS: -- INDIA: Prabhuji and Srivastava (1977); A. K. Srivastava (1978a); G. C. Srivastava (1967b); G. C. Srivastava and R. C. Srivastava (1977e); R. C. Srivastava (1976); R. C. Srivastava and G. C. Srivastava (1978a); PHILIPPINES: Dogma (1975). UNITED STATES: Clausz (1970, 1974); Farr and Paterson (1974); T. W. Johnson (1956a); Klich (1980); Rossy-Valderrama (1956); Slifkin (1964); Sorenson (1964); TeStrake (1958, 1959). SPECIMENS EXAMINED: -- ICELAND (1), NORWAY (5), TWJ. OCEANIA (18), UNITED STATES (28), RLS.

Achlya intricata Beneke J. Elisha Mitchell Sci. Soc. 64:261, pl. 29. 1948 (Figure 69 A-D)

Monoecious. Mycelium moderately extensive, dense near the substratum; hyphae stout, sparingly to abundantly branched. Sporangia fusiform or naviculate, occasionally long-cylindrical; renewed sympodially, rarely in basipetalous succession; 51-748 x 15-50 µm. Spores monomorphic; discharge and behavior achlyoid, with cluster often partially disintegrating, infrequently aplanoid; primary spore cysts 11-13 µm in diameter. Gemmae cylindrical and often irregular with short projections near the distal or proximal end; terminal and intercalary; single or catenulate; occasionally disarticulating. Oogonia predominantly terminal, rarely lateral; hemispherical, cylindrical, obpyriform, irregular, or lobed, the lobes sometimes delimited by septa; hemispherical ones 55-95 x 35-62 µm, lobed or cylindrical ones 50-200 x 17-125 µm, with lobes or lateral extensions up to 128 µm long. Oogonial wall pitted only under the region of antheridial cell attachment; smooth. Oogonial stalks long, slender; twisted or

517 irregular; unbranched. Oospores maturing or not, oospheres occasionally to frequently aborting; eccentric; spherical, flattened at one side from mutual pressure or ellipsoidal to broadly cylindrical in the lobes of the oogonia; (4-) 8-14 (-31) per oogonium, and usually filling it; (14-) 20-25 (-45) µm in diameter; at germination producing a short, slender germ hypha bearing a small, terminal, cylindrical sporangium. Antheridial branches diclinous; slender, irregular, moderately to abundantly branched; often wrapping loosely or partially about the oogonium and subtending hypha; persisting. Antheridial cells simple or compound; tubular or short- or long-clavate, occasionally irregular and once-branched; persisting; laterally appressed, very rarely attached by digitate projections; fertilization tubes not observed.

The distinctive, often irregular or asymmetrical oogonia (Fig. 69 A-D) of Achlya intricata develop in a narrow zone of the mycelium adjacent to the substratum, and usually appear only in cultures 3-5 weeks old. Small bits of hempseed endosperm (or whole seeds) are more likely to support oogonium-producing colonies of this species than are hempseed halves. The reason for such “preference” is not known. It is possible that Achlya intricata had been described by J. V. Harvey, in 1942, as A. pinnulata. Beneke (loc. cit.) recognized the similarities between these two species, but considered that since the lobed oogonia of Harvey’s species were alleged to be produced rarely the two were not the same taxon. While it is true that the description of A. pinnulata would suffice also for A. intricata, the illustrations of Harvey’s species do not impress one as representing Beneke’s taxon. In any case, A. pinnulata is an illegitimate name, and is excluded. The first written record of Achlya intricata appears under the name A. contorta (Beneke, 1948b). That name, however, was preempted by Cornu (1872: 25, figs. 9-15).

CONFIRMED RECORDS: -- ICELAND: Howard et al. (1970:69, fig. 21). UNITED STATES: Beneke (loc. cit.; 1948b:77, pl. 4); T. W. Johnson (1956b:62, pl. 11, figs. A, B); Milanez (1966:80, pl. 15); Milanez and Beneke (1968:16, pl. 3, figs. 1-3). RECORDED COLLECTIONS: -- UNITED STATES: R. L. Butler (1952)(?). SPECIMENS EXAMINED: -- ICELAND (2), TWJ, K. L. Howard. MWD (1); failed to produce oospores.

Achlya inflata Coker and Braxton In, Coker, J. Elisha Mitchell Sci. Soc. 42:211, pl. 29. 1927 (Figure 69 E-G)

Monoecious. Mycelium dense, limited, hyphae slender, moderately to abundantly branched. Sporangia sparse; cylindrical or fusiform, straight, curved, or slightly irregular; renewed sympodially; 75-815 x 14-36 µm. Spores monomorphic; discharge and behavior achlyoid; cluster sometimes falling away in part from orifice; primary spore cysts 10-12 µm in diameter. Gemmae sparse; clavate, obpyriform, or subspherical, occasionally cylindrical or irregular; terminal or intercalary, single or

518 catenulate. Oogonia lateral, rarely terminal, very rarely intercalary; spherical, rarely obpyriform or napiform, very rarely dolioform or angular; immature ones occasionally proliferating; (49-) 120-150 (-180) µm in diameter. Oogonial wall pitted; smooth, infrequently with 1-8 papillate or cylindrical projections. Oogonial stalks (1-) 2-3 (-6) times the diameter of the oogonium, in length; slender; straight, curved, or noticeably irregular. Oospores often not maturing, or developing then aborting; eccentric when mature; spherical; (1-) 6-12 (-24) per oogonium, but not filling it; (20-) 30-35 (-40) µm in diameter; germination not observed. Antheridial branches sparse; diclinous, slender, slightly irregular or twisted; usually unbranched, but occasionally producing 1-3 short, lateral, nonfunctional protrusions; not persisting. Antheridial cells simple; tubular, faintly clavate or irregular, but sometimes very large and irregular; unbranched or branched; attached in a digitate fashion, infrequently laterally appressed; persisting; fertilization tubes rarely observed, and apparently not persisting.

The large, spherical, conspicuously pitted oogonia on very slender, long stalks (Fig. 69 F) identify this species. It can be recognized readily by these characteristics and the fact that the oospores do not fill the oogonial cavity (Fig. 69 G). The names of the authors of the species do not appear in the publication first describing this taxon. Coker and Matthews (1937) attribute the name and diagnosis to Coker and Braxton.

CONFIRMED RECORDS: -- ICELAND: T. W. Johnson (1974b:8, fig. 118). UNITED STATES: Coker (loc. cit.); T .W. Johnson (1956b:59, pl. 11, figs. C-E). RECORDED COLLECTIONS: -- CANADA: Dick (1971c; as an aggregate species). UNITED STATES: G. C. Hughes (1959, 1962); T. W. Johnson (1956a); Klich (1980); Slifkin (1964). SPECIMENS EXAMINED: -- AUSTRALIA (1), RLS. ICELAND (2), OCEANIA (2), RLS. UNITED STATES (2), one preserved specimen, TWJ, RLS.

Achlya oviparvula Rogers and Beneke Rickia 1:244, pl. 1. 1962 (Figure 73 D-G)

Monoecious. Mycelium diffuse, moderately extensive; hyphae stout or slender, moderately branched. Sporangia cylindrical, fusiform, or naviculate; occasionally with one or two lateral exit tubes; straight or faintly irregular; renewed sympodially; 200-704 x 38-57 µm. Spores monomorphic; discharge and behavior achlyoid; primary spore cysts 11-14 µm in diameter. Gemmae spherical, obpyriform, cylindrical, ovoid, or broadly fusiform; terminal or intercalary, single or catenulate. Oogonia lateral, occasionally formed in discharged sporangia; spherical, angular, or slightly irregular, subglobose, broadly oval, or obpyriform; (15-) 20-24 (-31) µm in diameter, including wall projections, if any. Oogonial wall unpitted, or pitted only under region of attachment of antheridial cells; smooth; occasionally with one or two short- or elongate-

519 papillate projections. Oogonial stalks (1-) 3-4 (-9) times the diameter of the oogonium, in length; slender, curved, sinuous, bent, or irregular; unbranched or very sparingly branched. Oospores eccentric; spherical, ellipsoidal, or compressed from mutual pressure; 1(-3) per oogonium, and when single not filling it; (8-) 15-18 (-20) µm in diameter; germination not observed. Antheridial branches extremely rarely produced, but when present, diclinous; irregular, branched, contorted, and irregular; persisting. Antheridial cells tubular or clavate; persisting; attached in a digitate fashion; fertilization tubes not observed.

Achlya oviparvula has no counterpart among the species of Achlya with eccentric oospores. It is recognizable at once by its very small oogonia and small oospores (commonly one only in each oogonium). The only specimen we have seen of Achlya oviparvula produced in extremely rare instances abundantly branched and irregular antheridial filaments (Fig. 73 G). These branches did not regularly form visible antheridial cells. The specimens recovered and isolated by A. L. Rogers and Beneke (loc. cit.) were described as lacking antheridia.

CONFIRMED RECORD: -- SOUTH AMERICA: A. L. Rogers and Beneke (loc. cit.; also mentioned, without name, by Beneke and Rogers, 1962); Beneke and Rogers (1970:57). SPECIMEN EXAMINED: - MWD (1)

Achlya caroliniana Coker Bot. Gaz. (Crawfordsville) 50:381, figs. 1-8. 1910. (Figure 71 B-F)

Monoecious. Mycelium limited, dense; hyphae slender, sinuous, branched. Sporangia moderately abundant or rare; fusiform or cylindrical; straight, curved, or irregular, occasionally strongly bent at apex; frequently provided with one to several lateral discharge tubes or orifices; renewed sympodially, occasionally by cymose branching; 100-480 x 25-70 µm. Spores usually monomorphic; discharge and behavior achlyoid, occasionally aplanoid; primary spore cysts 8-10 µm in diameter. Gemmae variable in abundance; cylindrical, irregular, occasionally naviculate, obpyriform; branched or unbranched; terminal or intercalary, single or catenulate. Oogonia lateral, occasionally intercalary, infrequently terminal, rarely sessile; spherical, subspherical, obpyriform, or ovoid, occasionally or only rarely dolioform, infrequently angular or irregular, very rarely apiculate; sometimes proliferating; (21-) 35-45 (-76) µm in diameter, inclusive of any wall ornamentations. Oogonial wall pitted or unpitted; smooth or with one to several papillate ornamentations, infrequently with one to a few cylindrical or elongate-conical, straight or curved projections; very rarely crenulate. 1 Oogonial stalks ( /2-) 1-2 (-5) times the diameter of the oogonium, in length; slender, usually curved or irregular, branched or unbranched; apex usually protruding prominently into the oogonial cavity. Oospores eccentric; spherical or ellipsoidal; 1-4 (-

520 12) per oogonium and usually not filling it; (12-) 20-24 (-40) µm in diameter; at germination forming a slender, unbranched germ hypha producing a small, terminal, clavate sporangium. Antheridial branches absent, sparse or abundant, and occasionally not attached to or associated with oogonia; when present, monoclinous or diclinous, rarely androgynous; long or short, slender, irregular or moderately contorted, unbranched or sparsely to abundantly branched, not persisting. Antheridial cells simple; tubular or irregular, occasionally faintly clavate; persisting; attached laterally or in a digitate fashion; fertilization tubes not observed.

It is possible to recognize Achlya caroliniana using a combination of structural features associated with the oogonia. These cells are predominantly spherical (Fig. 71 C), but some individual specimens may on occasion possess one or two obvious papillae, or tubular to long-conical projections from the wall (Fig. 71 B, D). Nearly all the oogonia of an isolate reported by T. W. Johnson (1956a) were papillate. The oogonia generally contain two eccentric oospores, but three or four are to be found in some oogonia. Often the oogonia lack attached antheridial branches (Fig. 71 B, E), although an antheridial apparatus is characteristic (T. W. Johnson, 1956b) of some isolates of the species. In their general aspect, the oogonia of Achlya caroliniana bring to mind those of A. cambrica, and this resemblance is especially prominent when the oogonia of the latter are sparsely papillate. There are usually more oospores in the oogonia of A. cambrica than in those of A. caroliniana, and the antheridial apparatus is regularly produced by the former, but often is absent in the latter in some specimens. Achlya subterranea also produces some oogonia with sparse wall ornamentations, but otherwise it can be distinguished easily from A. caroliniana: abundant antheridial branches, and antheridial cells attached to raised orifices on the oogonial wall. There have been conflicting reports of oospore types in some of the descriptions of Achlya caroliniana, and whether or not antheridial branches were formed. These matters are reviewed adequately by T. W. Johnson (1956b). See Achlya bonariensis for a discussion of its striking similarity to A. caroliniana. The A. caroliniana collected by A. Lund (1934) had no antheridial branches, and only 1-2 oospores in the oogonia. He was not certain of the oospore type in his material, and because the specimen was mixed with A. racemosa, Lund also was in doubt about the asexual elements of Coker’s species. The figures provided by A. Lund (1934: fig. 10b, c) bring to mind A. bonariensis. Achlya pacifica (an illegitimate name; J. V. Harvey, 1942) was based on a variant of Coker’s species, and is excluded. Chiou et al. (1975: 162, pl. 1, figs. 7-9) described a collection of A. caroliniana (from Taiwan) as having a hypogynous antheridial apparatus when male filaments were lacking. The illustrations accompanying the description of their watermold do nothing to support the identification. Coker (1914) contended that the primary spores of Achlya caroliniana were flagellate at discharge, and thus the asexual stage of the species would have to be recognized as dimorphic not monomorphic. His observations have not been confirmed.

521 Barksdale (1960) used Achlya caroliniana in her study of interthallic (interspecific) matings of homothallic (monoecious) and heterothallic (dioecious) species. In pairings between A. ambisexualis (three strains) and A. caroliniana (two strains), the former acted as a female thallus for the latter, and mating proceeded to the formation of oogonial initials. (4 strains) responded as a female thallus for A. caroliniana (both strains used), but the mating did not progress beyond the development of antheridial branches. There was no positive reaction in pairings between Coker’s species and other monoecious taxa.

CONFIRMED RECORDS: -- AUSTRALIA: Cookson C1937:241). BRITISH ISLES: Forbes (1935a:229, pl. 8, fig. 1). CZECHOSLOVAKIA: Cejp (1959a:134, fig. 38). DENMARK: A. Lund (1934:26, fig. 10 b, c). GERMANY: Richter (1937:250). INDIA: R.C. Srivastava (1976: pl. 5, fig. B). IRAQ: Muhsin (1977:65, figs. A-G). JAPAN: Nagai (1931: pl. 5, fig. 13). NEW ZEALAND: R. F. Elliott (1967b:419). UNITED STATES: Coker (loc. cit.; 1923:122, pl. 41); Coker and Braxton (1926: pl. 12, fig. 7); Farr and Paterson (1974: fig. 2); J. V. Harvey (1942:27, pl. 4, figs. 1-7); T. W. Johnson (1956a:187; 1956b:87, pl. 10, figs. D, E, pl. 21, figs. E-K); A. W. Ziegler (1948b:23, pl. 4, fig. 11; 1952:9, pl. 3, fig. 7). USSR: Domashova (1971:192, fig. 7). RECORDED COLLECTIONS: -- AFRICA: Alabi (1967; 1971a, b; 1973). BRITISH ISLES: Dick 1963, 1966); Dick and Newby (1961); Cook and Forbes (1933); Cook and Morgan (1934); O’Sullivan (1965); Willoughby and Collins (1966). INDIA: Mekrani (1980); G. C. Srivastava and R. C. Srivastava (1977c, e, g). REPUBLIC OF CHINA: Chiou et al. (1975:162, pl. 1, figs. 7-9)(?). UNITED STATES: R. L. Butler (1975: figs. 73-76); Coker (1914, 1927); J. N. Couch (1927); J. V. Harvey (1925a, b, 1927b, 1930); G. C. Hughes (1959, 1962); C. E. Miller (1965); Paterson (1967); Scott (1960b); Te Strake (1958); A. W. Ziegler (1958b). WEST INDIES: Coker (1927); J. N. Couch (1927). YUGOSLAVIA: Ristanović (1973). SPECIMENS EXAMINED: -- AUSTRALIA (3), CENTRAL AMERICA (2), OCEANIA (3), RLS. NORWAY (1), SWEDEN (1), TWJ. UNITED STATES (7), RLS, TeStrake, J. N. Couch (preserved specimen). Centraalbureau (1).

Achlya pseudoachlyoides (Beneke) Johnson and Seymour Mycotaxon 92:11-32, figs. 31-35. 2005, and present fig. 75 G-K

Dictyuchus pseudoachlyoides Beneke, J. Elisha Mitchell Sci. Soc. 64:263, pl. 30. 1948. Basionym

Monoecious. Mycelium extensive, dense; hyphae slender, moderately branched. Sporangia cylindrical or clavate, usually slightly curved or sinuous; renewed sympodially or cymosely; 93-562 x 14-32 µm. Spores monomorphic; discharge and behavior achlyoid from primary sporangia, achlyoid, dictyucoid, or rarely aplanoid from secondary ones; primary spore cysts 10-13 µm in diameter. Gemmae usually abundant; spherical, oval, or cylindrical; single or catenulate, generally intercalary, and

522 often developed immediately below a sporangium. Oogonia lateral; spherical or obpyriform, infrequently subspherical; (22-) 28-32 (-48) µm in diameter. Oogonial wall 1 1 sparingly pitted or unpitted; smooth. Oogonial stalks (2-) 2 /2 – 3 /2 (-8) times the diameter of the oogonium, in length; slender, irregular, upright or recurved; unbranched or once-branched, but not forming oogonia in a glomerulus; oospores eccentric; spherical; single, and not filling the oogonium or nearly so; (17-) 22-28 (-41) µm in diameter; at germination, forming a short, unbranched germ hypha bearing a small, fusiform, achlyoid sporangium, or a branched germ hypha producing mycelium directly. Antheridial branches androgynous, very rarely monoclinous; slender, irregular, twisted, branched or unbranched; persisting; occasionally reverting to the production of sporangia or oogonia. Antheridial cells simple; small, tubular or irregular, often curved or sharply bent; persisting; laterally or apically appressed; fertilization tubes not observed.

The primary sporangia of Dictyuchus pseudoachlyoides are invariably achlyoid in their discharge in all the living specimens we have examined, and Beneke (loc. cit.) so described them in the original report. Secondary sporangia commonly are either predominantly achlyoid or dictyucoid in their manner of spore release, and in our isolates, one or the other type does not disappear as the culture ages. Thus, there is ample structural evidence for assigning Beneke’s species to Achlya. This merger of course alters the traditional concept of Achlya such that species with only one oospore per oogonium are now included in the genus. Achlya pseudoachlyoides is like A. achlyoides with respect to its sporangial types, and the single-egged nature of its oogonia (Fig. 75 G-K). The oogonia in A. pseudoachlyoides are smooth whereas they are ornamented (Fig. 75 C-E) in A. achlyoides. The predominance of multiple androgynous antheridial branches is a prominent expression (Fig. 75 G, H, J) in A. pseudoachlyoides. The single specimen of Dictyuchus (=Achlya) pseudoachlyoides recovered by T. W. Johnson (1956a) from soil was a variant of this species. The oogonial walls of the isolate generally were pitted (unpitted in this species according to Beneke), and monoclinous antheridial branches were as frequent as androgynous ones. Oogonia in the isolate described by Johnson were predominantly 37-42 µm in diameter, thus were somewhat larger than Beneke described for his specimens.

CONFIRMED RECORDS: -- IRAQ: Muhsin (1977:18, figs. A, B); Rattan et al. (1978:114, figs. 4, 5). UNITED STATES: Beneke (loc. cit.; 1948b:114, pl. 5); R. L. Butler (1975: figs. 181-184); T. W. Johnson (1956a:189, figs. 1-4). SPECIMENS EXAMINED: -- UNITED STATES (2), TWJ, and E. S. Beneke (subculture and preserved specimen of type).

Achlya orion Coker and Couch J. Elisha Mitchell Sci. Soc. 36:100. 1920 (Figures 73 A-C, 74 E-I)

523

Monoecious. Mycelium diffuse, extensive; hyphae slender, branched to varying degrees. Sporangia cylindrical or clavate, infrequently fusiform; straight, curved, or slightly irregular; renewed sympodially, occasionally cymosely or in a basipetalous manner; 45-700 x 17-52 µm. Spores monomorphic; discharge and behavior achlyoid; primary spore cysts 9-11 µm in diameter. Gemmae, when present, cylindrical to irregular, infrequently branched; terminal or intercalary, single or catenulate. Oogonia lateral, rarely terminal; spherical or napiform, rarely slightly angular, ovoid, or short-cylindrical, immature ones infrequently proliferating; (20-) 40-60 (-93) µm in diameter. Oogonial wall pitted under region of antheridial cell attachment, infrequently elsewhere as well; smooth, or with wall substance occasionally protruding 3 in a low, truncate profile through pits. Oogonial stalks ( /4-) 1-3 (-12) times the diameter of the oogonium, in length; slender or stout; usually bent and strongly recurved, or curved to moderately sinuous, occasionally to infrequently twisted sharply, or loosely or tightly coiled; rarely straight; infrequently branched. Oospores eccentric; spherical, or ellipsoidal or pyramidal from mutual pressure; 1-2 (-12) per oogonium, and when more than one usually filling it; (16-) 25-35 (-48) µm in diameter, germination not observed. Antheridial branches, when present, predominantly androgynous or monoclinous, rarely to very infrequently diclinous; usually short when androgynous or monoclinous; irregular, unbranched or sparingly branched; occasionally twisted, or loosely coiled; persisting. Antheridial cells simple; tubular to clavate, and often irregular; occasionally lobed or branched; persisting; attached in a digitate manner; fertilization tubes usually prominent and persisting.

Achlya orion can be identified by its generally spherical oogonia (containing one or two oospores) terminating long, slender, bent or recurved stalks (Figs. 73 A, 74 E-G). In some isolates, androgynous (Fig. 74 G-I) antheridial branches predominate, but Milanez (1970) has reported mostly monoclinous filaments in his Brazilian material. We have collected two specimens of A. orion in Sweden and two from Nigeria in which slightly more than 60% of the antheridial branches were monoclinous, and approximately 30% were androgynous. The Swedish watermolds had 2-4 oospores in most oogonia, whereas in all other individuals we have examined of this species oogonia with only 1-2 oospores predominate. In its general morphology, Achlya orion resembles two other species. Comparing Achlya brasiliensis with A. orion, Milanez (1965) found sufficient differences to separate them readily. A close structural similarity exists, however, between Achlya orion and A. rodrigueziana. Like A. rodrigueziana, A. Orion has long-stalked, smooth-walled oogonia, commonly a single eccentric oospore in the oogonium, and digitate antheridial cells. The antheridial branches in the former are predominantly diclinous (very rarely androgynous), almost the reverse of the condition met in the latter. Most of the oogonia in A. orion are pitted, but in A. rodrigueziana the inner surface of the wall of the majority of oogonia is minutely roughened to noticeably irregular.

524 CONFIRMED RECORDS: -- BRITISH ISLES: Forbes (1935a:230). CZECHOSLOVAKIA: Cejp (1959a:140) fig. 41). GERMANY: Richter (1937:248, fig. 9). INDIA: Dayal and Thakur Ji (1968c:32, figs. 5-13); Manoharachary (1979a:190, pl. 1, fig. Prabhuji (1979:73, pl. 8, fig. 9); G. C. Srivastava (1967a:286, pl. 3, figs. 2,3); R. C. Srivastava (1976: pl. 3, fig. B). JAPAN: Okane (1976:2, fig. 3). RUMANIA: Toma (1969:291, pls. 4, 6). SOUTH AMERICA: Beneke and Rogers (1962:186); T. W. Johnson (1956b:67, pl. 14; pl. 15, figs. F-O); deLyra and Milanez (1974:9, fig. 6); Milanez (1970:28, figs. 1, 2). UNITED STATES: Beneke (1948b:66); R. L. Butler (1975: figs. 89-92); Coker (1923:112, pls. 34 (lower fig., 35); Coker and Couch (loc. cit.); Overman (1970:24). WEST INDIES: T. W. Johnson (see entry, South America). RECORDED COLLECTIONS: -- BRITISH ISLES: Cook and Forbes (1933); Hunter (1975); GERMANY: Höhnk (1935a, 1958). INDIA: Manoharachary (1974); Mekrani (1980); Prabhuji and Srivastava (1977); Mer et al. (1980); G. C. Srivastava (1967b); G. C. Srivastava and R. C. Srivastava (1977e); R. C. Srivastava (1978); R. C. Srivastava and G. C. Srivastava (1978a); Thakur Ji (1967). RUMANIA: Toma (1971). UNITED STATES: Clausz (1970, 1974); Coker (1927); Coker and Braxton (1926); G. C. Hughes (1959, 1962); T. W. Johnson (1956a); K. B. Raper (1928); A. W. Ziegler (1958b). WEST INDIES: Sparrow (1952a); Sparrow and Dogma (1973). SPECIMENS EXAMINED: -- AFRICA (3), CENTRAL AMERICA (1), OCEANIA (7), SOUTH AMERICA (3), WEST INDIES (2), RLS. SWEDEN (2), TWJ. UNITED STATES (5), RLS.

Achlya irregularis (Coker and Ward) Johnson and Seymour Mycotaxon 92:11-31, figs. 14-17. 2005, and present fig. 76A-D

Thraustotheca irregularis Coker and Ward, in, M. W. Ward, J. Elisha Mitchell Sci. Soc. 55:348, pl. 31. 1939. Basionym

Monoecious. Mycelium dense; hyphae slender, branched. Sporangia cylindrical, fusiform, or clavate, occasionally irregular; straight, curved, bent, or branched; renewed sympodially, cymosely, or in basipetalous succession; extremely variable in size. Spores monomorphic; discharge and behavior achlyoid in primary sporangia, but thraustothecoid, achlyoid, dictyucoid, or aplanoid in secondary ones; wall of achlyoid sporangia eventually deliquescing in whole or part; primary spore cysts 9-14 µm in diameter. Gemmae abundant; spherical, pyriform or obpyriform, oval, clavate, or fusiform; terminal or intercalary, single or catenulate. Oogonia lateral, rarely terminal or intercalary; obpyriform, oval, or infrequently spherical; (20- ) 40-55 (-72) µm in 1 1 diameter. Oogonial wall pitted; smooth. Oogonial stalks ( /2-) 1-1 /2 (-3) times the diameter of the oogonium, in length; stout, straight, curved, or slightly irregular; usually tapering to a narrow base from a wide distal end; unbranched. Oospores frequently aborting, or oospheres not maturing; eccentric when mature; spherical; (1-) 4- 8 (-l4) per oogonium, but usually not filling it; (10-) 18-22 (-38) µm in diameter; germination not observed. Antheridial branches diclinous; long, slender, irregular, and

525 usually sparingly branched; occasionally partially clasping the oogonium or winding loosely about it; persisting. Antheridial cells simple or compound; tubular, clavate; moderately to sparsely branched or unbranched, often long, twisted, and irregular, or long-cylindrical and clasping the oogonium; persisting; attached in a digitate fashion or laterally appressed; fertilization tubes not observed.

Coker and Ward (M. W. Ward, loc. cit.) were more than once explicit in their account that the primary sporangia of this species were achlyoid. We find the same to be true (Fig. 76 A) in the specimens we have examined. While the secondary sporangia of our isolates were largely thraustothecoid, achlyoid ones were not eliminated through repeated subculturing. Accordingly, we are transferring Thraustotheca irregularis to Achlya. Assignment of this species to Achlya, however, may not be the final disposition of the taxon. Coker and Ward were careful to note that the achlyoid sporangia produced by their fungus deliquesced entirely or in part after the spores were released. Our specimen did not display such a feature, but if it is characteristic of other representatives of the species, there would then be further evidence for the very close kinship of Achlya and Thraustotheca (see also A. dubia). If emptied sporangia of the Achlya type deliquesce, as in Thraustotheca, are they properly to be considered achlyoid? Without question, Achlya irregularis closely resembles A. dubia, sharing a similarity in such characteristics as antheridial branch origin, failure of oospheres to mature (or tendency of oospores to abort), and the production of achlyoid and thraustothecoid sporangia. Furthermore, the features on which Coker and Ward distinguished their species from A. dubia (oogonium wall color, for example) are, from our experience, of little or no taxonomic value. Lacking convincing evidence to the contrary, we are retaining both Achlya irregularis and A. dubia, but admitting also that this may prove to be untenable in the future. Based on our examination of isolates we are able to separate the two taxa on three characteristics primarily. First, the oogonia of A. irregularis are predominantly -- and prominently -- broadly obpyriform (Fig. 76 B-D); in A. dubia, spherical or napiform ones (Fig. 67 A, D) are most common. Second, the thraustothecoid sporangia of A. dubia disappear from specimens that are repeatedly subcultured, but do not do so in A. irregularis. Third, oospore abortion or failure of oospheres to mature is more common in A. irregularis than in A. dubia. We are satisfied that only an analysis of the products of zygote germination is likely to reveal whether or not these characteristics are stable enough to support the recognition of the two species. Coker and Ward (M. W. Ward, loc. cit.) found that their Thraustotheca irregularis would produce sexual structures only when the mycelium was cultured on small bits of hempseed, or on nutrient-poor substrates. We have not seen this to be a necessary prerequisite for sex cell formation in our isolate. In any event, we are not certain that a small segment of a hempseed is a priori a nutrient-depleted substratum.

CONFIRMED RECORD: -- UNITED STATES: Coker and Ward (in M. W. Ward,

526 loc. cit.). SPECIMENS EXAMINED: -- CENTRAL AMERICA (1), SOUTH AMERICA (2), UNITED STATES (2), RLS.

Achlya debaryana Humphrey Trans. Amer. Phil. Soc. (N.S.) 17:117. 1893 (Figures 71 G-I, 72)

Achlya polyandra de Bary non Hildebrand, Abh. Senckenberg Naturf. Ges. 12:273 et sqq., pl. 4, figs. 5-12.1881. Achlya debaryana var. intermedia Minden, Kryptogamenfl. Mark Brandenburg 5:45. 1912. Pieters, Bot. Gaz. (Crawfordsville) 60:487, pl. 21, figs. 1-4.1915. Achlya flagellata Coker, Saprolegniaceae, p. 116, pl. 37. 1923. Achlya imperfecta Coker, ibid., p. 118, pls. 38, 39. 1923. Achlya conspicua Coker, ibid., p. 131, pls. 45, 46 (upper fig.). 1923. Achlya oryzae Ito and Nagai, in Nagai, J. Fac. Agric. Hokkaido Imp. Univ. 32:17, pl. 4, figs. 3-11. 1931. Achlya flagellata var. yezoensis Ito and Nagai, in Nagai, ibid., p. 22, pl. 5, figs. 20-22; pl. 6, fig. 2. 1931. Achlya kashyapia Chaudhuri and Kochhar, Proc. Indian Acad. Sci. (Sect. B) 2:145, pl. 9, figs. 1-10. 1935. Achlya klebsiana var. indica Chaudhuri and Lotus, Proc. Indian Acad. Sci. (Sect. B) 3:328, pl. 2.1936. Achlya androcomposita Hamid, Proc. Indian Acad. Sci. (Sect. B) 15:211, pl. 2. 1942. Achlya klebsiana var. kashyapia Chaudhuri, in Chaudhuri, et al. Handbook Indian Water Moulds, Part I, p. 46, fig. 21. 1947. Achlya michiganensis Johnson, Mycologia 42:393, fig. 2. 1950.

Monoecious. Mycelium limited or extensive, diffuse, but often dense near the colony periphery; hyphae stout or slender, sparingly to moderately branched. Sporangia fusiform or naviculate, occasionally cylindrical; straight, curved, or irregular, and sometimes bent near the terminal exit pore; rarely branched except when produced in basipetalous succession; occasionally provided with lateral exit pores or tubes; renewed sympodially, occasionally or rarely cymosely, or in basipetalous succession; 78-1125 x 10-53 µm. Spores monomorphic; discharge and behavior achlyoid, infrequently or rarely dictyucoid or aplanoid; spore cluster persisting or falling away from the exit orifice; primary spore cysts 8-12 µm in diameter. Gemmae extremely variable in abundance, shape, and position. Oogonia lateral, infrequently or rarely terminal, very rarely intercalary; spherical or obpyriform, infrequently angular or subglobose, occasionally oval, very rarely dolioform; sometimes proliferating; (20-) 45- 70 (-147) in diameter. Oogonial wall pitted, unpitted, or pitted only under the region of 1 antheridial cell attachment; pits occasionally obscure; smooth. Oogonial stalks ( /4-) 1-3 (-8) times the diameter of the oogonium, in length; stout, straight, curved, or irregular;

527 very rarely branched. Oospores may or may not mature, or oospheres may abort; when mature, eccentric, spherical or ellipsoidal, occasionally pyramidal from mutual pressure; (1-) 2-14 (-48) per oogonium, and filling it or not; (15-) 20-28 (-57) µm in diameter; at germination forming a branched mycelium or an unbranched germ hypha producing a terminal, fusiform or cylindrical sporangium. Antheridial branches predominantly diclinous or monoclinous, and of near or distant origin; infrequently or rarely androgynous; ratio of diclinous to monoclinous branches extremely varied; occasionally not attached to any oogonia; slender, long or short; irregular, unbranched or branched; sometimes closely appressed to the oogonium and clasping it; persisting or deliquescing. Antheridial cells simple or compound; tubular, clavate, or slightly irregular; unbranched or once-branched; persisting; generally attached in a digitate fashion, infrequently or occasionally laterally appressed; fertilization tubes present or absent, persisting or not.

Specimens of Achlya having the following combination of characteristics are recognized as A. debaryana: (1) smooth, generally spherical or obpyriform, unpitted or pitted oogonia on slender stalks usually about as long as the oogonial diameter (or slightly longer); (2) eccentric oospores (they may abort or the oospheres do not develop) that usually fill the oogonial cavity or nearly so, and (3) prominently displayed, unbranched to moderately branched, predominantly diclinous and monoclinous antheridial filaments that may originate at points quite remote from the oogonia to which they are attached. Achlya debaryana has some features in common with A. americana, but the two diverge in the nature of the monoclinous antheridial branches. In A. americana, most oogonia are attended by monoclinous filaments of near origin (Fig. 77 A), and diclinous branches are certainly uncommonly encountered. The monoclinous antheridial branches of A. debaryana, on the other hand, generally are remote (Fig. 72 A, G) from the oogonium to which they are attached. There are other eccentric-egged representatives of Achlya having a sexual apparatus that structurally recalls A. debaryana, but each has one or more prominent features to set them apart from Humphrey’s species. Achlya cambrica and A. caroliniana, have some ornamented oogonia, but A. debaryana does not. The oogonia of A. diffusa generally are large and obpyriform, and there are inflated hyphal swellings in that species that A. debaryana lacks. The report by Milanez (1970:27, figs. 16-19) of diffusa-like swellings in A. flagellata needs confirmation. Isolates displaying such swellings probably were more closely akin to A. diffusa than to A. flagellata. Like A. prolifera, A. debaryana produces diclinous antheridial branches, but in the latter these do not coil and wrap profusely about the oogonia. Moreover, A. prolifera does not develop monoclinous antheridial filaments. Achlya proliferoides also is marked by strongly coiling antheridial hyphae) a feature not to be seen in Humphrey’s species. The production by A. orion and A. rodrigueziana of relatively long oogonial stalks surmounted by small, spherical oogonia with 1-3 oospores (generally) easily separate these species from A. debaryana.

528 It is immediately evident that our treatment of Achlya debaryana is a radical departure from the conservative approach to the taxonomy of the A. flagellata- A. klebsiana-A. conspicua galaxy taken by T. W. Johnson (1956b). He recognized that there were structural similarities among these species, and admitted that their taxonomy was by no means fixed. Later he (T. W. Johnson, 1974b) postulated that specimens he had of the “klebsiana-debaryana” complex only proved that the two were but one species. Other investigators also had commented from time to time on the difficulties encountered in trying to identify individual members of this flagellata-klebsiana group, and expressed their dissatisfaction with the taxonomic accounts available. Without a doubt, numerous misidentifications have been perpetrated because this complex of very similar taxa was so poorly circumscribed. Accounts by Richter (1937:251, fig. 11), Dogma (1966), Dick and Newby (1961), Domashova (1971), Cejp (1959a:159, fig. 49), and Chiou et al. (1975: 163, pl. 1, fig. 10, among others, are illustrative. In retrospect, we believe that the changes authored by T. W. Johnson (1956b) for Achlya flagellata, A. klebsiana, A. conspicua, and A. debaryana were in each case adequately justified. The complex was not analyzed thoroughly enough, however, resulting in very conservative taxonomic decisions. We have examined more than 200 isolates of this cluster of species, collected from many geographical regions, and are satisfied that these four taxa can no longer be retained as separate entities. Coker (1923) described three seemingly closely related species -- Achlya flagellata, A conspicua, and A. imperfecta (considered a synonymous species by T. W. Johnson in 1952) -- but did very little to point out meaningful dissimilarities among them. He singled out for comment characters of the sporangia and gemmae of these taxa, but such structures are notoriously of little taxonomic value in the family. Pieters (1915c: 484) evidently saw specimens of A. debaryana, but gave little attention to how this species could be distinguished from A. klebsiana. He described A. klebsiana as having only diclinous antheridial branches and unpitted oogonial walls. Specimens of the type of this species, however, displayed some monoclinous antheridial filaments, and there are pits in the walls of a few oogonia (T .W. Johnson, 1956a). Thus the type specimen itself allies A. klebsiana immediately to A. debaryana. Achlya flagellata was first reported by Coker (1912a) under the name A. debaryana. He declared that A. debaryana was the most abundant watermold he had encountered. Because the specimens he studied had pitted oogonia and androgynous (monoclinous) antheridial branches, Coker concluded that they did not represent de Bary’s A. polyandra (renamed debaryana by Humphrey). Coker (1912a:323, pl. 78, fig. 13) also singled out for comment the fact that in A. debaryana the monoclinous (he referred to this condition as androgynous) antheridial branches were of distant origin. In 1923, however, Coker noted that the specimens he earlier had identified as A. debaryana could not be of that species because they produced androgynous (monoclinous) filaments of near origin. Accordingly, he proposed the new species, A. flagellata, to designate those specimens he had earlier identified as A. debaryana. This decision by Coker is curious since both he (1912a: pl. 78, fig. 13; 1923: pl. 37, fig. 1) and de Bary (1881: pl. 4, fig. 5)

529 depict monoclinous antheridial branches of remote origin for A. flagellata and A. debaryana, respectively. The presence or absence of wall pitting in the oogonia would appear to be the only remaining characteristic on which Achlya flagellata and A. debaryana can be distinguished from one another. According to de Bary (loc. cit.), his A. polyandra (=debaryana of Humphrey) lacked pits in the oogonia, but the one specimen of the species in the de Bary collection at the British Museum (Natural History) displays some faintly and very sparsely pitted oogonia (Fig. 71 G). Thus, the character of oogonium wall pitting does not figure into the separation of A. debaryana and A. flagellata. What is the evidence that Achlya conspicua is but a variant of A. debaryana (as this latter species is interpreted as including A. flagellata and A. klebsiana)? As has been shown, oogonial wall pitting is a variable feature in all these taxa. Antheridial branch origin in A. conspicua is primarily androgynous or monoclinous, and seldom diclinous (Coker, 1923:131). This would seem at once to separate A. conspicua from all other members of this cluster of species. When many isolates are examined, however, considerable variation in the frequency of antheridial branch types is seen, and this feature loses its taxonomic impact. For example, there are flagellata-like isolates in our collections in which about 60% of the oogonia are attended by androgynous antheridia. Other isolates, indistinguishable from these in all other features, have no androgynous filaments whatsoever. As to the nature of the antheridial branches themselves, there is considerable variation among isolates. It has been demonstrated experimentally as well (T. W. Johnson, 1974b) that in some debaryana- and klebsiana-like isolates the degree of branching in antheridial filaments is modified by culture conditions. Thus, the fact that A. conspicua generally is alleged to have unbranched filaments is not important taxonomically. In the description of Achlya conspicua Coker (1923:131) described the oospores as rarely maturing, but “...apparently about like those of A. apiculata when in normal condition...”, in which case they were subcentric. The illustrations he provided show no recognizable oospore structure. Rossy-Valderrama (1955) found eccentric oospores in a fungus she believed to be A. conspicua. Thus, the species itself is ill-defined. As has been shown by T. W. Johnson (1952) the frequency of oosphere maturation in the A. flagellata-A. imperfecta complex is exceptionally variable and this also is true of conspicua-like specimens. Of the seven isolates of A. conspicua examined by Howard and his associates (1970) two had almost no mature oospores, and in five, 11-73% of the oogonia (300 each isolate) contained eccentric oospores). Thus it is clear that A. conspicua cannot be separated from A. flagellata (as earlier defined by Johnson) on the basis of this characteristic. In his remarks on A. conspicua Coker (1923:131) commented upon the tendency of the oogonial stalk to flare upward (into the oogonial cavity) at the juncture with the oogonium. He referred to this tendency as “...often...exaggerated...” but his illustrations in no way convey a sense of prominence of this feature, and we find in it no support for setting A. conspicua aside as a distinct species. We have tallied dimensions of the oogonia and oospores in some 75 % of the specimens (of this five-species complex) that we have recovered from soil and water.

530 The raw data demonstrate that individual specimens identifiable with one of the species (sensu stricto) in the galaxy of five under consideration can have sex cell measurements that overlap with those of individuals characteristic of some other taxa in the group. This is likewise the case with oospore number: a highly diverse range is encountered when a large spectrum of isolates is examined. The shape, position, size, and behavior of the asexual structures in the individuals we have examined are much too inconstant to be dependable either in setting species limits or simply in routinely identifying specimens. An accurate appraisal of the taxonomic problem with the smooth-walled, eccentric-egged species was made by T. W. Johnson (1974b:9), namely that repeated attempts “...to sort out these Achlyas into reasonably recognizable species units invariably ended in indecisive naming.” The flagellata-debaryana-klebsiana-conspicua- imperfecta complex of forms has a positive parallel in the Saprolegnia ferax-mixta-monoica galaxy treated by Seymour (1970). He discovered intergrades between these species as well as precisely identifiable individuals. When the whole assemblage of isolates was studied comparatively, however, the individuality faded, just as we have found. Hence, a broad yet recognizable-species concept is indicated, with debaryana having nomenclatural priority. As broad as is our concept of A. debaryana it is not as sweeping as the view held by Dick and Newby (1961). They referred to A. f1agellata as an aggregate species that included A. dubia, A. intricata, A. prolifera, A. diffusa, and A. klebsiana. Achlya conspicua has been singled out as a probable intermediate between A. flagellata and A. americana (T. W. Johnson, 1956a, 1974b). The comparative morphological study by T. W. Johnson and Seymour (1974a) of A. americana demonstrated that this species is surprisingly stable in those characters most critical to its recognition. It certainly does not vary toward the conspicua forms of A. debaryana. Evidence of a nonmorphological nature for a close kinship among named members of the debaryana group, as we define it, is scanty. Two accounts of experimental work are pertinent in this regard. Barksdale (1960) found that Achlya flagellata reacted sexually in specific ways in interspecific pairings with A. bisexualis and A. ambisexualis. Achlya ambisexualis served as the oogonial or antheridial “donor” to various strains of A. flagellata, and in matings where a positive reaction occurred oogonial or antheridial initials were delimited. Successful matings between strains of A. bisexualis and A. flagellata were not frequent, but the dioecious species could act either as a male or female to the monoecious one. There were no oogonial initials produced in any of the positive matings between A. bisexualis and A. flagellata; successful interthallic crosses resulted only in the production of antheridial branches. Barksdale (1960) experimented with isolates identified as A. flagellata and A. conspicua in interspecific pairings between homothallic (monoecious) strains. Both of these species functioned as antheridial strains when mated with A. heterosexualis (identified in Barksdale’s 1960 paper as A. klebsiana). Achlya conspicua was the male to A. americana in one pairing, but the interspecific sexual reaction terminated with the formation of antheridial initials. Barksdale found that one strain of A. flagellata

531 reacted as an antheridial partner to A. caroliniana but the mating did not proceed beyond antheridial branch formation. The cross-stimulated sexual reproductive cycle was not completed (Barksdale, 1960) in any of the matings involving the members of the A. debaryana complex, but the results obtained at least do not contradict our merger of A. flagellata and A. conspicua. The second line of experimental work having possible taxonomic implications in the Achlya flagellata-A. klebsiana complex is the analysis of DNA base composition values published by Storck and Alexopoulos (1970). They reported GC values of 55% for Achlya flagellata, and 44.5% for A. klebsiana, and concluded that these two species thus belonged to separate groups. In 1972, however, B. R. Green and Dick reported that DNA base composition data could be of some taxonomic value at the generic level. The spectrum of Achlyas they analyzed was limited and thus inconclusive at the species level. The chromosome numbers recorded (Dick, 1978) for Achlya flagellata (n= 6), and A. klebsiana (n=ca. 12) do not support our contention that these two taxa are the same. These numbers, however, have not been independently confirmed. Barbier’s (1971a) study of an isolate initially identified as Achlya flagellata, is particularly pertinent (Chapter 9). He propagated subcultures of a specimen in a constant incubation environment for ten years, seeking any structural changes that might occur during that period. The percentage of androgynous antheridial branches produced by the fungus declined to a very low level during the first two years of subculturing, and then such “male” hyphae were no longer produced in subsequent years. Monoclinous antheridia also were less frequent after two years, and by the end of the decade, the number of such branches in subcultures was far exceeded by diclinous ones. Barbier attributed the change in antheridial origin to mutation, having ruled out, he thought, any environmental influences by maintaining a precisely reproducible and constant set of culture conditions. During the extended period of subculturing, the isolate “progressed” through, as it were, the distinguishing characteristics of what Barbier believed were three “natural” geographical varieties: that found in the U. S. (A. flagellata), a European form (A. debaryana), and an Indian one (A. androcomposita). Some of the specimens identified by collectors as one of the taxa which we have now merged with Achlya debaryana were probably incorrectly named. The fungus described as Achlya conspicua by Kobayasi et al. (1967) is only provisionally accepted as is that reported by Rose (1932). Richter’s (1937) specimen of the same species was doubtless a form of A. americana, and is so treated. The watermold identified by Nagai (1931: pl. 5, figs. 13, 18) as A. flagellata possibly was A. caroliniana. Dudka and Florinskaya (1971), and Domashova (1971) recovered A. flagellata in their sampling, but the accompanying illustrations depict fungi resembling A. americana. The description of an Indian specimen of A. klebsiana by Chaudhuri et al. (1947:44) contains obvious contradictions, and Cejp’s (1934:189, pl. 1, figs. 8-10) account of the same species was based on a mixed culture. Achlya klebsiana strain B-4 used by Barksdale (1960) in interspecific matings among monoecious (homothallic) species was later (Barksdale,

532 1965) identified as A. heterosexualis. Vasudeva (1960) proposed that the name A. polyandra (Hildebrand) de Bary used by E. J. Butler and Bisby (1931) for a watermold collected in India be rejected. Earlier, A. Fischer (1892:352) also had equated de Bary’s A. polyandra incorrectly with Hildebrand’s species. It is very likely that in both these latter cases, A. debaryana was incorrectly identified. Poorly described and inadequately illustrated, Achlya kashyapia Chaudhuri and Kochhar (loc. cit.) is closely allied to the A. klebsiana element of A. debaryana. Chaudhuri and Kochhar themselves believed their species to be no more than a variety of A. klebsiana. An appropriate disposition of A. kashyapia was not reached by T. W. Johnson (1956b) who considered the taxon to be one of unknown affinities. Several unidentified (or unnamed) Achlyas in the literature were in all likelihood variants of A. debaryana (sensu lato). Achlya sp. 2 described by T. W. Johnson (1956b:99, pl. 12, figs. C-I) seems, in light of more extensive evidence, to have been a form with some conspicua-like structural features. The unnamed isolates characterized by Dogma (1966:57, 66, figs. 11-14) might well be included among the variant representatives of A. debaryana. A relationship with A. debaryana also seems indicated for Achlya sp. 2 and 3 described by Kobayasi and Konno (1971:382, 384, figs. 4: K-O, 5). The oospore type was not described for these fungi, and the authors expressed uncertainty as to the range of antheridial branch origin; the illustrations call to mind forms near A. conspicua.

CONFIRMED RECORDS: -- AFRICA: Alabi (1967: pl. 11, figs. C-E); Goldsmith (1948:138, pl. 15, figs. 4, 5); Hutchison (1940:12, figs. 12, 16-18); Nolard-Tintigner (1974: figs. 1, 6). AUSTRALIA: Cookson 1937: 240); Crooks (1937:212, fig. 2 C-E). BRITISH ISLES: R. A. Couch (1951:74, pls. 7, 8); Forbes (1935a:227, 229; 1935b: 9, fig. 4). CANADA: C. L. Moore (1908-09:224, figs. 5-8). CENTRAL AMERICA: T. W. Johnson (1956b:77, pl. 18). CZECHOSLOVAKIA: Cejp [1934:189, pl. 1, fig. 16; 1959a:142, 144, 151, 159(?), figs. 43, 44, 46, 49(?)]. DENMARK: A. Lund (1934:25, figs. 9, 10a). FRANCE: Moreau and Moreau (1938:235, 237, p1s. 4; 5; 6, figs. 12-19; 10, figs. 1-13; 22, 23). GERMANY: de Bary (1881:273 et sqq., pl. 4, figs. 5-12); Bock (1956:34, pl. 2, figs. 1, 2); A. Fischer (1892:352; figs. 54b; 55c, d); Horn (1904:207 et sqq., figs. 1-21); Mäckel (1928: fig. 23); Minden (loc. cit.; 1912:544, fig. 2e); Mücke (1908: pl. 6); Pringsheim (1882a: pl. 14, figs. 1-11, 13, 14); Richter (1937:248, 249, fig. 10); Zopf (1890:296, fig. 45). ICELAND: Howard et al. (1970:70); T. W. Johnson (1974b:5 et sqq., 8, figs. 111-117). INDIA: Chaudhuri (loc. cit.); Chaudhuri and Kochhar (loc. cit.; 1935:143-147; pl. 8, figs. 1-20; pl. 9, figs. 11-17; pl. 10, figs. 1-8; pl. 11, figs. 9-13); Chaudhuri and Lotus (loc. cit.); Chaudhuri et al. (1947:34, 35, 37[?], 41-43, 46, figs. 11, 13, 14[?], 17-20); Dayal (1958:56, pl. 5); Hamid (loc. cit.); Khulbe (1977:13-15, pl. 1, figs. 2, 3; pl. 5, figs. 4-8; 1980c:77, 78) Manoharachary (1979a:189, 190, pl. 1, figs. E, F; 1979b:198, pl. 1, figs. 2, 3); Prabhuji (1979:73, pl. 7, figs. 7, 8); S. B. Saksena and Rajagopalan (1958:11, 13, figs. 18-28); G. C. Srivastava (1967a: 289, 290, pl. 4, figs. 1, 2); R. C. Srivastava (1976: pl. 4, fig-A). IRAQ: Muhsin [1977:74(?), 76, figs. A, B, A-D(?) (two plates)]. JAPAN: Indoh (1937:298, pl. 14, figs. 7-9); S. Ito (1936:84, 85, figs. 33.1, 33.5, 34.1, 34.3); T. Ito (1942:125, 127, fig. 2a-c; 1944: 53); Kobayasi and Konno (1969:730, fig. 4A-E); Kobayasi and Ookubo (1952a:104-

533 106, figs. 4-6); Kobayasi and Watari (1934:724, figs. 69, 70); Nagai (locc. citt.; 1931:20, 22, pl. 5, figs. 12, 14-22; pl. 6, figs. 1, 2); Okane (1976:1, figs. 1, 2; 1977: figs A, B); Ookubo (1954:49, fig. 39). LATVIA: Apinis (1929a:229, 230, pl. 4, figs. 2,3,6). MIDDLE EUROPE: Migula (1903:69). NEW ZEALAND: R. F. Elliott (1967b:420, fig. 2). PEOPLE’S REPUBLIC OF CHINA: Ou (1940:435, 436); Shen and Siang (1948:194). PHILIPPINES: Dogma [1966:22, 32, 54, 57(?), 66(?), figs. 5-7, 11-14(?)]. POLAND: Staniak (1971:360); Szwanke (1938:10, 11, pl. 3, fig. 13; pl. 4, figs. 1, 2, 12); Zaborowska (1965:45, fig. 7). REPUBLIC OF CHINA: Chiou et al. [1975:163(?), 164, pl. 1, fig. 10 (?), 14, 15; pl. 2, fig. 16)]; Chung (1973: fig. 4); Sawada (1912:10); Volz et al. (1974:231, fig. 2). RUMANIA: Moruzi and Toma (1968: pl. 2, figs. 18-20; pl. 3, figs. 24-26; pl. 5, figs. 36, 37). SOUTH AMERICA: Beneke and Rogers (1962:187, pl. 1, figs. 1-4; 1970: 56); Beroqui de Martinez (1970:119, 121,122, figs. IA-E, 3A-C, E-G); T. W. Johnson (1956b:74, pl. 15, figs. A-E; pl. 16); deLyra and Milanez (1974:9, fig. 5); Milanez (1968:99-101, figs. 9, 10; 1970:27, figs. 16-19); A. L. Rogers et al. (1970:100). UNITED STATES: Beneke (1948b:69, 72, 74, 86); Bretsnyder (1943:13, 14); R. L. Butler (1975: figs. 97-100, 113-120); Coker (locc. citt.; 1912a:319 et sqq., pl. 78; 1923:120, pl. 40); Hubschman and Schmitt (1969: fig. 2); Hutchison (1940:12, 15, figs. 11, 12, 16-18); T. W. Johnson (loc. cit.; 1956a:187; 1956b: 77, 99, pl. 12, figs. C-I, and pl. 18; see also entry, South America); Kobayasi et al. [1967:10, text fig. 2(?)]; Milanez (1966:77, 78, 81); Milanez and Beneke (1968:16); Overman (1970:18, 21, 23); Pieters (loc. cit.); Rajagopalan (1963:117, fig. 1 M-P); Rose [1932:38, 40, pl. 3, fig. 27; pl. 4, figs. 28, 29; p1. 5, figs. 38, 39(?)]; Rossy-Valderrama (1955:19, 27, 35, pl. 1, figs. 1-4; pl. 3; pl. 4, figs. 5-7; pl. 6, figs. 14-20; 1956:135 et seq.); Shipman (1977: fig. 10); Sorenson (1962: pl. 1, figs. A-C; pl. 2, figs. A-C; pl. 3, figs. A, B); Wolf (1938: figs. 1-9; 1944: 28, pl. 2, fig. 13); A. W. Ziegler (1948b:22, pl. 4, figs. 3-10; 1952:8, 9,pl. 3, figs. 2, 5, 6). USSR: Domashova [1971: fig. 6(?)]; Dudka and Florinskaya (1971:434, 435, figs. 4, 5(?); Florinskaya [1969:114, fig. 9(?); 1971; fig. 1(?)]; Morochkovs’kii et al. (1967:135, 138, figs. 122, 124, 125); Naumov (1954: 71); Shkorbatov (1927:77). WEST INDIES: T. W. Johnson (see entry, South America). RECORDED COLLECTIONS: -- AFRICA: Alabi (1967; 1971a, b; 1973). AUSTRIA: H. Braun (1893). BRITISH ISLES: Apinis (1964); Cook and Forbes (1933); Cook and Morgan (1934); Dick (1962, 1963, 1966); Dick and Newby (1961); Forbes (1935b); B. R. Green and Dick (1972); Hunter (1975); O’Sullivan (1965); Perrott (1960); R. E. Roberts (1963); Trow (1904); Willoughby (1965). CENTRAL AMERICA: Shanor (1944); Wolf (1939b); Wolf and Wolf (1941). DENMARK: A. Lund (1978). FRANCE: Barbier (1969); Volkonsky (1934). GERMANY: Höhnk (1935a, 1956a); Schlösser (1929); Stoll (1936). ICELAND: Howard et al. (1970); T. W. Johnson (1968, 1974b). INDIA: Bhattacharya and Baruah (1953); E. J. Butler and Bisby (1931); Dayal and Tandon (1962, 1963); Dayal and Thakur Ji (1965, 1966); Khulbe (1980a); Khulbe and Bhargava (1977); Manoharachary (1974); Mekrani (1980); Prabhuji (1979); Prabhuji and Srivastava (1977); G. C. Srivastava (1967b); G. C. Srivastava and R. C. Srivastava (1975b, 1976a, 1977e); R. C. Srivastava and G. C. Srivastava (1978a); Sydow et al. [1907; as A. polyandra (Hildebrand) de Bary]. IRAQ: Al-Saadi et al. (1979). JAPAN: Hoshina et al. (1960); T. Ito (1944); S. Ito and Nagai (1931); Kobayashi and Ôkubo (1954); Okane (1967, 1978);

534 Ookubo (1954); Ookubo and Kobayasi (1955); Suzuki (1960a, b, d, f, h; 1961a, b, d-f, i, j, l; 1962a-c, e; 1964); Suzuki and Hatakeyama (1960, 1961); Suzuki and Nimura (1960, 1961d); Suzuki and Tatsuno (1965a,b). NEW ZEALAND: Karling (1966f). OCEANIA: Karling (1968b). PHILIPPINES: Dogma (1975). POLAND: Staniak (1971); Palczewska and Jagodzka (1972). REPUBLIC OF CHINA: Liu and Volz (1977). RUMANIA: Toma (1969, 1971). SOUTH AMERICA: Karling (1944a, b); Upadhyay (1967). UNITED STATES: Barksdale (1960); Beneke and Schmitt (1961); Clausz (1970, 1974, 1979); Coker (1927); Coker and Braxton (1926); W. B. Cooke (1968, 1969); W. B. Cook and Bartsch (1959, 1960); W. B. Cooke and Matsuura (1969): Cotner (1930b); J. N. Couch (1927); Farr and Paterson (1974); J. V. Harvey (1925a, b; 1927b 1930, 1952); G. L. Hoffman (1949); Höhnk (1935a); G. C. Hughes (1959, 1962); T. W. Johnson (1950b; 1956a); Kauffman (1906)(?); Klich (1980); V. D. Matthews (1935); Monsma (1936); Nesom (1969); Padgett (1978a, 1980); Paterson (1967); Pieters (1915a); Poitras (1955); K. B. Raper (1928); Rooney and McKnight (1972); Rossy-Valderrama (1956); Salvin (1941); Schmitt (1967); Schmitt and Beneke (1962); Scott (1960b); Shipman (1979); Slifkin (1964, 1967a); Sorenson (1964); Sparrow (1952b); TeStrake (1958); W. N. Tiffney (1936); W. N. Tiffney and Wolf (1937); Tontz (1969); M. W. Ward (1939); R. K. Webster et al. (1970); Whiffen (1945); Wolf and Wolf (1941); A. W. Ziegler (1958b). USSR: Domashova (1971, 1974b); Dudka (1965, 1966); Érgashev and Kirgizbaeva (1978); Kirgizbaeva et al. (1975); Logvinenko and Meshcheryakova (1971); Mil’ko (1965); Mil’ko and Belyakova. (1968); V. E. Miller[a] (1906); Osipyan et al. (1974). WEST INDIES: Coker (1927); J. N. Couch (1927); Sörgel (1941); Sparrow (1952b); Sparrow and Dogma (1973). YUGOSLAVIA: Ristanović (1970a, b; 1973); Ristanović and Ritter-Studnička (1970). SPECIMENS EXAMINED: -- AUSTRALIA (8), CENTRAL AMERICA (10), RLS. NORWAY (84), SWEDEN (57), TWJ. OCEANIA (10), RLS. UNITED STATES (121), RLS, TWJ; preserved type of Achlya klebsiana, A. J. Pieters: preserved type of A. conspicua, W. C. Coker. WEST INDIES (17), RLS. Centraalbureau (1).

Achlya cambrica (Trow) Johnson Genus Achlya, p. 85, pl. 17, figs. E-I. 1956 (Figure 68 A-E)

Achlya americana var. cambrica Trow, Ann. Bot. (London) 13:135, pls. 8-10. 1899.

Monoecious. Mycelium dense, limited; hyphae moderately stout and branched. Sporangia fusiform or naviculate, rarely cylindrical; straight, curved, or slightly irregular; renewed sympodially or occasionally in basipetalous succession; 98-400 x 15-62 µm. Spores monomorphic; discharge and behavior achlyoid, rarely dictyucoid; spore cluster not persisting at exit orifice; primary cysts 10-14 µm in diameter. Gemmae absent. Oogonia lateral, infrequently terminal, rarely intercalary; angular, spherical, subspherical, ovate, or pyriform, rarely dolioform; (28-) 46-65 (-93) µm in diameter, exclusive of wall ornamentations. Oogonial wall pitted under region of antheridial cell attachment, occasionally or infrequently sparsely pitted elsewhere as

535 well; provided with one to a few papillate projections, which in some instances are merely wall substance protruding through pits, or infrequently with 1-4 long, cylindrical or tapering, straight or curved projections; occasionally or frequently 1 1 smooth. Oogonial stalks ( /4-) 1-1 /2 (-3) times the diameter of the oogonium, in length; slender, usually slightly curved or irregular, occasionally bent; unbranched or once- branched. Oospores eccentric; spherical or ellipsoidal, broadly oval, or slightly flattened from mutual pressure; (l-) 3-6 (-28) per oogonium, and usually not filling it; (15-) 24-28 (-38) µm in diameter, at germination forming a slender, unbranched or sparingly branched germ hypha which may or may not bear a small, terminal, fusiform sporangium. Antheridial branches usually present, predominantly monoclinous or androgynous, but frequently to rarely diclinous in some specimens; short or long, unbranched or sparingly to abundantly branched; irregular, curved; short antheridial hyphae persisting, but long and profusely branched ones often disintegrating as culture ages. Antheridial cells simple or compound; tubular, clavate, or irregular, persisting; laterally appressed or attached by short or very prominent digitate extensions; fertilization tubes present, not persisting.

In conformity with Coker’s (1923:112) opinion, T. W. Johnson (loc. cit.) raised Trow’s Achlya americana var. cambrica to specific rank, but also recognized that it was a species very closely allied to A. flagellata (=debaryana) and A. americana. Achlya cambrica has fewer and smaller oospores than A. americana, and produces papillate oogonia on occasion. The latter characteristic also serves to distinguish A. cambrica from A. debaryana. These features still appear reliable in the taxonomy of the three species. Monoclinous antheridial branches predominated in the Achlya cambrica reported by T. W. Johnson (loc. cit.) and Howard et al. (1970). In two variants of A. cambrica (from Iceland) 68-73% of the antheridial branches were diclinous (T. W. Johnson, 1974b); this contrasts with a noticeable infrequency of such filaments in other specimens of this species (for example, Howard et al., 1970). The antheridial cells in the Iceland specimens recovered by Johnson were much longer and more prominently displayed than had previously been noted for A. cambrica. Large antheridial cells are not uncommon in A. americana (Fig. 77 C; T. W. Johnson, 1974b: fig. 108; T. W. Johnson and Seymour, 1974a: figs. 16-19). The frequent diclinous antheridial branches found in some representatives of Achlya cambrica allies it closely to A. debaryana, and future study may show the two to be variants of a single taxon. For the present, the occasional papillate oogonia in A. cambrica and the absence of these in A. debaryana (as it is understood to embrace A. flagellata, A. klebsiana, and A. conspicua) seems adequate to separate the two. Four watermolds recovered from soils in Iceland were included in a composite description published by T. W. Johnson (1974b:13, figs. 139-145). He did not name the isolates, but suggested that they might represent forms of Achlya cambrica. Only one of the isolates survived subculturing, and consequently nothing is known of the ranges of variation expressed by these fungi. It is impossible to assign the Iceland specimens

536 (TWJ 4144, 4147, 4529, 8858) to any known species in the genus, pending some future analysis of additional and similar isolates.

CONFIRMED RECORDS: -- BRITISH ISLES: Trow (loc. cit.). CANADA: C. L. Moore (1908-09:223). ICELAND; Howard et al. 1970: fig. 16); T. W. Johnson (1974b:75, figs. 102-107). RECORDED COLLECTIONS: -- AFRICA: Alabi (1967, 1971b, 1973). INDIA: Dayal and Tandon (1962, 1963). UNITED STATES: Klich (1980). SPECIMENS EXAMINED: -- ICELAND (7), NORWAY (1), TWJ. OCEANIA (2), SOUTH AMERICA (6), WEST INDIES (12), UNITED STATES (3), RLS. Centraalbureau (1); preserved specimen.

Achlya americana Humphrey Trans. Amer. Phil. Soc. (N.S.) 17:116, pl. 14, figs. 7, 9, 10; pl. 15, figs. 18, 21, 24, 25, 29; pl. 16, figs 30-36; pl. 18, figs. 69-73. 1893. (Figure 77 A-C)

Achlya polyandra forma americana Petersen, Bot. Tidsskr. 29:385, figs. 3g. 1909. (Also in Ann. Mycol. 8:524, fig. 3g. 1910) Achlya ocellata Tiesenhausen, Arch. Hydrobiol. Planktonk. 7:287, fig. 14. 1912. Achlya debaryana var. americana Minden, Kryptogamenfl. Mark Brandenburg 5:545. 1912. Achlya americana var. megasperma Crooks, Proc. Roy. Soc. Victoria (N.S.) 49:212, fig. 3 E- H. 1937. Achlya sp. 1, Johnson, Genus Achlya, p. 97, pl. 20. 1956.

Monoecious. Mycelium limited or extensive, diffuse or dense; hyphae stout, sometimes stiff; sparingly branched, in some strains terminating in a branched, sharply tapering configuration, the branches densely protoplasmic. Sporangia fusiform, naviculate, cylindrical, or clavate; straight or curved, sometimes irregular; renewed sympodially, rarely in a cymose fashion; 66-950 x 11-65 µm. Spores monomorphic; discharge and behavior achlyoid; primary spore cysts 9-12 µm in diameter. Gemmae abundant or sparse; cylindrical, fusiform, or irregular; usually terminal and single, occasionally intercalary and catenulate. Oogonia lateral, occasionally terminal; spherical, obpyriform, or napiform, rarely pyriform or oval; (24-) 48-70 (-152) µm in diameter, in some strains median range of 62-118 µm in diameter. Oogonial wall pitted; 1 1 smooth. Oogonial stalks ( /16-) /2 - l (-3) times the diameter of the oogonium, in length; stout; straight, curved, or irregular; unbranched. Oospores eccentric; spherical, occasionally oval or ellipsoidal; (1-) 6-14 (-> 120) per oogonium, and usually filling it but in some specimens, median number of oospores 16-32; (11-) 20-28 (-42) µm in diameter; at germination producing a slender, unbranched or sparingly branched germ hypha bearing a small, terminal, fusiform sporangium. Antheridial branches predominantly monoclinous, rarely diclinous, very rarely androgynous; stout or slender, branched, unbranched, nearly isodiametric, or conspicuously irregular or

537 swollen at intervals; in some isolates, long, slender, profusely branched, and coiled, but this latter condition not persisting; filaments persisting. Antheridial cells simple or compound; tubular, clavate, expanded, or irregular; attached by short or long projections, rarely laterally appressed; persisting; fertilization tubes sometimes present, not persisting.

Achlya americana is a very common species in temperate regions and usually is quite easily recognized by the general configuration of the sexual apparatus. The oogonia are often racemosely arranged on the principal hyphae (Fig. 77A), are generally short-stalked (Fig. 77B), and contain several oospores that usually fill the oogonial cavity. Attending the majority of mature oogonia of most specimens are short, unbranched or sparingly branched, monoclinous antheridial filaments of near origin (Fig. 77A, B). The most extreme forms known of A. americana were described in 1974(a) by T. W. Johnson and Seymour. Two specimens (from Iceland) produced very stout, stiff hyphae, terminating in one or more short, tapering, densely protoplasmic branches (Fig. 77C; see also T. W. Johnson and Seymour, 1974a; figs. 18-21). The oogonia generally were very large and filled with numerous, small oospores. The female apparatus was attended by much-branched, short, contorted or irregular monoclinous antheridial filaments (Fig. 77C) terminated by very large, conspicuous antheridial cells attached in a prominently displayed digitate fashion. Two other isolates (also from Iceland) retained the general configuration characteristic of A. americana (see foregoing paragraph) but additionally formed some very extensive; noticeably branched and coiled monoclinous antheridial filaments. These unusual filaments did not persist in subcultures. Achlya americana has from time to time been confused (Richter, 1937) with A. debaryana (sensu lato), but in the latter the antheridial branches are of a more diverse origin than in A. americana, the oogonial stalks are generally longer and more slender, and there are fewer oospores per oogonium. Sometimes the oospores fail to mature or may abort, a condition not found in A. americana. See A. heterosexualis (a self- and cross- conjugating species) for an account of its structural similarities to A. americana. A detailed morphological study by T. W. Johnson and Seymour (1974a) of 21 isolates of Achlya americana collected in Iceland demonstrated some of the extremes of variability encountered in this species. Employing for the most part the morphological parameters used by Dick (1969a) in his study of Scoliolegnia (=Saprolegnia) species, Johnson and Seymour grouped the isolates into nine recognizable series. From both qualitative observations and quantitative analyses it was clear that the specimens exhibited gradation toward one another in some characters and disjunction in others. Moreover, certain pronounced and unusual characteristics of some isolates (coiling antheridial filaments, for example) proved to be unstable in culture. The extreme morphologies displayed by the various isolates – for example small oogonia with few oospores, and very large oogonia with many oospores -- were transcended by intermediates. Johnson and Seymour found that no more than three characteristics in

538 one isolate, and a single feature in most others, could be used to separate one series of specimens from any other. This fact, of course, was diametrically opposed to Dick’s (1972) view that recognition of a new taxon must be based on more than disjunction in one or two characters, and that a mere range of intermediates did not justify synonymy. To be sure, the nine series of isolates (T. W. Johnson and Seymour, 1974a) of Achlya americana could be distributed into two groups, but solely on the single character of mean oospore diameter. The specimens all exhibited abundantly pitted, smooth oogonia, small oospores, and monoclinous antheridial branches of near origin (Dick, 1969b, regarded such filaments as “being closely monogynous”). Hence, despite divergences in, for example, the sizes of reproductive units and degree of antheridial filament branching, the individuals displayed the basic morphology that Humphrey (loc. cit.), recognized as circumscribing A. americana. Species synonymous with Achlya americana were proposed by T. W. Johnson (1956b), and save for brief comment need not again be justified. Johnson was not the first to treat von Minden’s (loc. cit.) A. debaryana var. americana as a synonym of Humphrey’s species; that change had been proposed earlier by Ookubo (1954). Dick and Newby (1961) viewed A. americana as an aggregate species that included A. conspicua, A. debaryana, and A. cambrica [taxa with eccentric oospores and androgynous (their term) antheridial branches]. Dick (1973:138 later, however, did not list Humphrey’s species as an aggregate. Two isolates reported in 1974(b) by T. W. Johnson had some sympodial branches terminating in antheridial cells but were otherwise similar to Humphrey’s species in the configuration of the sexual apparatus. From an analysis of the characteristics of these specimens from Iceland, Johnson was able to identify as Achlya americana the Achlya sp. 1 described by him in 1956(b).

CONFIRMED RECORDS: -- AUSTRALIA: Crooks (loc. cit.). BRITISH ISLES: Forbes (1935a:228). CANADA: C. L. Moore (1908-09:223, fig. 4). CENTRAL AMERICA: T. W. Johnson (1956b:71, pl. 19, figs. E, F). CZECHOSLOVAKIA: Cejp (1959a:154, 156, fig. 47). DENMARK: Petersen (loc. cit.). GERMANY: Minden (loc. cit.); Richter (1937:246, 247, 251, figs. 8, 11; includes his records of Achlya conspicua and A. debaryana). ICELAND: T. W. Johnson (1974b:4, 5, figs. 108-110); T. W. Johnson and Seymour (1974a:245, figs. 1-21). INDIA: Chaudhuri and Kochhar (1935:142, pl. 7, figs. 1-11); Chaudhuri et al. (1947:31, fig. 10; possibly A. debaryana: illustration is not characteristic of A. americana); Khulbe (1977:12, pl. 5, figs. 1-3; pl. 9, fig. 1; 1980c:77); S. B. Saksena and Rajagopalan (1958:11, figs. 13-17); Thakur Ji (1970: figs. 26-28; possibly A. debaryana, judging from the illustrations). JAPAN: S. Ito (1936:83, fig. 34.2); Kobayas[h]i and Konno (1971a:9, fig. 3A, B); Kobayashi and Ôkubo (1954:562, fig. 4); Nagai (1931:16, pl. 3, figs. 22-25; pl. 4, figs. 1,2). PEOPLE’S REPUBLIC OF CHINA: Shen and Siang (1948:193). POLAND: Stpiczyńska (1962:105, fig. 7); Szwanke (1938:9, pl. 3, figs. 8-12); Zaborowska (1965: fig. 5). RUMANIA: Moruzi and Toma (1968: pl. 3, figs. 21-23; pl. 5, figs. 38). SOUTH AMERICA: Beneke and Rogers 1962:187; 1970:55) Beroqui de Martinez (1970:116, figs. 2A, 3K). SWITZERLAND: Tiesenhausen (loc. cit.). UNITED STATES: Beneke (1948b:63); Bretsynder (1943: 13); R. L. Butler (1975: figs. 93-96); Coker (1923:111,

539 pls. 33, 34); Hine (1878: pl. 6, fig. 15); Humphrey (loc. cit.); Hutchison (1940:11, fig. 13); T. W. Johnson (loc. cit.; 1956b:97, pl. 20). Milanez (1966:74, pl. 7, figs. d, e); O’Bier (1960:34, pl. 4, figs. h-k); Overman (1970:22); Rose (1932:42, pl. 3, figs. 25, 26); Rossy-Valderrama (1955:22 et sqq., pl. 1, figs. 5, 6; pl. 2; 1956:135); Scott and Warren (1964: figs. 2, 4); Sorenson (1962: pl. 4, figs. A, B); A. W. Ziegler (1948b:23, pl. 4, figs. 12, 13; possibly was A. conspicua). RECORDED COLLECTIONS: -- BRITISH ISLES: Cook and Forbes (1933); Dick (1962, 1963, 1966); Dick and Newby (1961); Hunter (1975); R. E. Roberts (1963). CANADA: Dick (1971c). DENMARK: A. Lund (1934). ICELAND: Howard et al. (1970). INDIA: Chowdhery and Rai (1980:238, pl. 1, figs. 1-3)(?); Dayal and Tandon (1962, 1963); Mer et al. (1980); G. C. Srivastava (1967b). JAPAN: S. Ito and Nagai (1931); Ookubo (1954); Suzuki (1961a, f, i; 1964); Suzuki and Hatakeyama (1961); Suzuki and Nimura (1961d); Suzuki and Nishita (1963); Suzuki and Tatsuno (1965a, b). LATVIA: Apinis (1929a). PHILIPPINES: Dogma (1975). POLAND: Stpiczyńska-Tober (1965); Zebrowska (1976a, b). RUMANIA: Toma (1969, 1971). UNITED STATES: Atkinson [1897. According to T. W. Johnson (1956b), Earle (1901) noted Atkinson’s record of this species from Alabama; this was an error; Mohr (1901) listed this record.]; Barksdale (1960); Beneke and Schmitt (1961); Clausz (1970, 1974); Coker (1927); W. B. Cooke and Bartsch (1959, 1960); W. B. Cooke and Matsuura (1969); Farr and Paterson (1974); Fox and Wolf (1977a); Graff (1928); J. V. Harvey (1952); G. C. Hughes (1959, 1962); T. W. Johnson (1950b; 1956a); Klich (1980); Kuehn (f960); Monsma (1936); Padgett (1978a, 1980); Poitras (1955); J. R. Raper (1950b); Rooney and McKnight (1972); Schmitt and Beneke (1962); Scott (1960b); Scott and O’Bier (1962); Slifkin (1964); Sorensen (1964); Sparrow (1952b); TeStrake (1958); M. W. Ward (1939); Wolf and Wolf (1941); A. W. Ziegler (1958b). USSR: Logvinenko and Meshcheryakova (1971); Mil’ko and Zakharova (1976). WEST INDIES: Sparrow and Dogma (1973). YUGOSLAVIA: Ristanović (1970a, 1973). SPECIMENS EXAMINED: -- AUSTRALIA (3), RLS. ICELAND (23), NORWAY (21), SWEDEN (13), TWJ, UNITED STATES (107), TWJ. OCEANIA (6), WEST INDIES (4), RLS.

Achlya rodrigueziana Wolf Mycologia 33:274, figs. 1-13. 1941 (Figure 74 A-D)

Monoecious. Mycelium dense, extensive; hyphae stout and moderately branched, or slender, irregular, and much-branched. Sporangia cylindrical or fusiform; straight or curved, often slightly irregular; renewed sympodially; 140-596 x 17-88 µm. Spores monomorphic; discharge and behavior achlyoid; primary spore cysts 10-12 µm in diameter. Gemmae cylindrical, occasionally irregular; terminal or intercalary, single or catenulate. Oogonia very abundant; lateral, rarely terminal; spherical, occasionally obpyriform, rarely obovate or apiculate; immature ones occasionally proliferating; (25-) 40-45 (-58) µm in diameter. Oogonial wall unpitted; smooth on outer surface, usually or

540 1 1 1 only occasionally irregular on inner surface. Oogonial stalks ( /4-) 1 /2-2 /2 (-6) times the diameter of the oogonium, in length; slender, straight, curved, sinuous, or irregular; rarely branched. Oospores eccentric; spherical, oval, or ellipsoidal, sometimes flattened at juncture with adjacent oospores; 1 (-4) per oogonium, and usually not filling it; (l9-) 26-32 (-4l) µm in diameter; germination not observed. Antheridial branches usually present; diclinous, rarely monoclinous, and then with a remote origin; extremely rarely androgynous; slender, irregular; branched or unbranched; persisting. Antheridial cells simple; tubular and irregular, or clavate, often bent or curved; persisting; attached in a digitate fashion; fertilization tubes usually present, persisting.

While Achlya rodrigueziana resembles A. orion in the general aspect of its sexual apparatus, the structural differences between these two taxa are substantial (see discussion of A. orion). Cejp (1959a:158), who considered it doubtful that Achlya rodrigueziana occurred in Czechoslovakia, nevertheless had the notion that his Achlya Hähneliana was possibly synonymous with Wolf’s species. This is unlikely because Cejp’s fungus (parasitized) seems to ally more readily with A. orion, especially when antheridial branch origin is considered. Beroqui de Martinez (1970:112) suspected that A. rodrigueziana might be synonymous with A. klebsiana (=debaryana), but we see no firm support for such a conclusion in the characteristics of the specimens we have examined.

CONFIRMED RECORDS: -- CENTRAL AMERICA: Wolf (loc. cit.). INDIA: Dayal and Thakur Ji (1969:171 et seq., figs. 7-11). NEPAL: Joshi (1976:44, fig. 2). SOUTH AMERICA: Beroqui de Martinez (1970:118, figs. 1F& G, 3L). UNITED STATES: Beneke (1948b:76); Fox and Wolf (1977:102, fig. 4); T. W. Johnson (1950b:399; 1956b:84, pl. 11, fig. F; pl. 17, figs. J-L). USSR: Meshcheryakova (1972:374, figs. 1-3). RECORDED COLLECTIONS: -- CZECHOSLOVAKIA: Cejp (1959a: 156, fig. 48). INDIA: Thakur Ji (1967). UNITED STATES: Schmitt and Beneke (1962); Scott (1960b); A. W. Ziegler (1958b). SPECIMENS EXAMINED: -- AFRICA (2), OCEANIA (1), WEST INDIES (1), RLS. CENTRAL AMERICA (1), preserved type, F. T. Wolf. UNITED STATES (12), TWJ, RLS.

Achlya prolifera Nees von Esenbeck Nova Acta Phys.-Med. Acad. Caes. Leop-Carol. Nat. Cur. 11:514, p. 58. 1823 (Figure 77 D-F)

Leptomitus prolifer Agardh, Systema Algarum, p. 48. 1824. Saprolegnia prolifera A. Braun, Betrachtungen über die Erscheinung der Verjüngung in der Natur., p. 268. 1851. Achlya aplanes Maurizio, Flora 79:135, pl. 4, figs. 28-31. 1894. Achlya flexuosa Nagai, J. Fac. Agric. Hokkaido Imp. Univ. 32:18, pl. 5, figs. 1-11. 1931. Achlya aplanes var. indica Saksena and Dayal, in Dayal, Proc. Natl. Acad. Sci. India, Sect. B, Biol. Sci. 28:56, pl. 4. 1958.

541

Monoecious. Mycelium extensive, diffuse; hyphae stout, moderately branched. Sporangia clavate, fusiform, or cylindrical; straight, curved, or slightly irregular; renewed sympodially, rarely cymosely; 105-980 x 25-55 µm. Spores monomorphic; discharge and behavior achlyoid, occasionally aplanoid; spores in cluster may germinate in situ, or spore mass may fall away from exit orifice; primary spore cysts 10- 12 µm in diameter. Gemmae cylindrical, occasionally irregular; terminal or intercalary, single or catenulate. Oogonia lateral, occasionally terminal, rarely intercalary, very rarely sessile; obpyriform, occasionally or only infrequently spherical, rarely obovate, very rarely angular or subglobose; (30-) 70-90 (-128) µm in diameter. Oogonial wall 1 pitted; smooth. Oogonial stalks ( /4 -) ½ -1 (-4) times the diameter of the oogonium, in length; straight or slightly irregular; tapering slightly toward the base, or nearly isodiametric throughout; unbranched. Oospores nearly always maturing, then eccentric; spherical, ellipsoidal, or oval; (1-) 6-16 (-40) per oogonium, and usually filling it; (l5-) 20-28 (-41) µm in diameter; at germination forming a short, unbranched hypha bearing a small, terminal sporangium. Antheridial branches diclinous; irregular, twisted, contorted; abundantly branched; wrapping about the oogonium and often covering it, and occasionally coiling sparingly around the hypha and oogonial stalk; not persisting. Antheridial cells simple or compound; tubular, clavate, or slightly irregular, infrequently branched or lobed; tending to clasp the oogonium when long; not persisting; laterally appressed, very rarely attached in a digitate manner; fertilization tubes present but not persisting.

The large, predominantly obpyriform oogonia attended by luxuriantly branched, diclinous antheridial hyphae define this species. In the clasping, wrapping aspect of the antheridia about the oogonia, Achlya prolifera has counterparts in A. bisexualis and A. ambisexualis, but the latter two are dioecious species (some strains are capable of interthallic mating), while A. prolifera so far as is known, is monoecious. Achlya proliferoides is recognized chiefly by the coiled antheridial filaments it produces (Fig. 70 G), and such a feature is also to be found in A. prolifera. In the latter, however, the tendency to coil is not as frequently or as prominently displayed as in A. proliferoides. Moreover, A. proliferoides produces some monoclinous antheridial branches; none is formed by A. prolifera. In his account of Achlya prolifera T. W. Johnson (1956b) treated the taxonomic history of the species in depth and this need not be repeated here. He singled out instances where A. prolifera was misidentified or very incompletely described. To the instances he cited, the following publications may be added: Unger (1843, 1844), Pringsheim (1851), Thuret (1850), Schröter (1889) Sawada (1912), and Pieters (1915a). There are other reports of A. prolifera in which the name obviously was misapplied, but the accompanying descriptive matter is so scanty or contradictory that it is impossible to tell with certainty which taxon actually was seen. Notable among such accounts are those by Cohn (1853), Cienkowski (1855), M. J. Berkeley (1864: figs. 10-12), Lindstedt (1872: 59), Sorokine (1889-90:142, pl. 12, figs. 180, 181), and T. Abe (1928:261 et sqq., pl. 2;

542 also in S. Ito, 1936). These records are excluded. The Achlya prolifera described by Sawada in 1912 probably was incorrectly identified just as Nagai (1931: 25) suspected. It is quite likely that Sawada (1912: pl. 7, figs. 3, 6; pl. 8, fig. 2) had at hand a mixed collection of specimens, since he illustrated some sporangia of A. prolifera as internally renewed. Sawada also committed Dictyuchus magnusii to synonymy with A. prolifera, but such a disposition is unacceptable. In 1919 (p. 45) Sawada again reported A. prolifera from Formosa (Taiwan), and stated that Takahashi’s (1918:432) Achlya sp. was synonymous with it. There is no way of being certain that either Sawada or Takahashi had in fact collected Nees von Esenbeck’s species. The collection of A. aplanes (=prolifera) by Chaudhuri and Kochhar (1935:148, pl. 12, figs. 1-10) is not identifiable either as this species or any other in the genus for that matter. The record of A. aplanes by Chaudhuri et al. (1947:34, fig. 12) likewise is excluded because it is too poorly described to be properly identified; perhaps the Indian fungus was A. oblongata. Howard et al. (1970:69) disposed of Achlya flexuosa Nagai as a synonym of prolifera. Barksdale (1962b:710), however, had earlier chosen to consider Nagai’s plant as a self-conjugating representative of A. bisexualis. We have commented on this merger in the discussion of the latter species. There is nothing in Nagai’s account to exclude A. flexuosa from A. prolifera, and until the taxonomy of dioecious Achlyas can be properly interpreted in light of genetic information, assignment of a monoecious species to equality with a dioecious one is not in order, in our view. It should be noted that Nagai (1931) believed the sexually sterile Achlyas described by Coker (1923:137), Emoto (1923), Humphrey (1893:83), and Weston (1917) were synonymous with A. flexuosa. Barksdale (1962b) contended, however, that all these nonsexual fungi were forms of A. bisexualis, and we agree that hers is a defensible (though at this point unprovable) disposition of them. Nagai, of course, based his decision on the similarity of the spherical gemmae produced by A. flexuosa and those formed by the four nonsexual watermolds. It is known that A. bisexualis also produces spherical gemmae, but this does not, ipso facto, support the merger of Nagai’s species with A. bisexualis. Finally, it may be recalled that T. W. Johnson (1956b:110) looked upon A. flexuosa as a species of unknown affinity, but thought that it was “...quite likely...” to be found ”..synonymous with A. prolifera...” Achlya aplanes Maurizio (loc. cit.) was based on specimens in which the spore behavior was aplanoid. As in situ spore germination is common in older cultures of A. prolifera, and all of its other major characters are like those of A. aplanes, the two have been merged (T. W. Johnson, 1956b). Saksena and Dayal (Dayal, loc. cit.), however, maintained A. aplanes as a valid taxon and described a new variety of it. The variety indica presumably differed from Maurizio’s species only by the fact that it produced some motile spores. The description of A. aplanes var. indica, however, is quite contradictory: the fungus is said not to have motile spores (Dayal, loc. cit., p. 56) but it is also recorded that “...(a few swimming zoo-spores were always observed).” The illustrations accompanying the description of A. aplanes var. indica (Dayal, loc. cit., pl. 4, figs. 7, 8) show an empty sporangium (indicative of spore release) and one discharged in an achlyoid manner. So far as we can determine, the fungus described by Saksena

543 and Dayal is only a form of A. prolifera exhibiting the usual variation in spore release and behavior to be expected in this species. According to Barksdale (1960), the sexual apparatus of certain hermaphroditic strains of Achlya ambisexualis resemble those of A. prolifera. She suggested that the heterothallic (dioecious) species might have been derived from a homothallic (monoecious) form such as A. prolifera (among other possibilities).

CONFIRMED RECORDS: -- AFRICA: Alabi (1967: pl. 12, fig. 4); Nolard-Tintigner (1974: figs. 4, 5). BRITISH ISLES: Forbes (1935b:7, fig. 3). CZECHOSLOVAKIA: Cejp (1959a:148, fig. 45). FRANCE: Cornu (1872: pl. 1, fig. 1). GERMANY: de Bary (1852: pl. 7, figs. 1-22, 26-28; 1881:273 et sqq., pl. 2, figs. 1, 2 pl. 4, figs. 1-4; 1888: 633); A. Braun (loc. cit.); A. Fischer (1892:353, figs. 55a, b); Mäckel (1928: fig. 24); Minden (1912:538, fig. 2b, d); Nees von Esenbeck (loc. cit.). ICELAND: Howard et al. (1970:69). INDIA: Chaudhuri and Lotus (1936:328); Chaudhuri et al. (1947: fig. 23); Dayal (loc. cit.; 1961a: figs. 1, 2); Dayal and Thakur Ji (1965:318, pl. 5); Prabhuji (1979:71, pl. 7, fig. 5); G. C. Srivastava (1967a:288, pl. 3, figs. 4, 5); R. C. Srivastava (1976: pl. 3, fig. A). IRAQ: Muhsin (1977:71, figs. A-F). JAPAN: Indoh (1937:1297, pl. 15, figs. 10-16); S. Ito (1936:85, pl. 34, fig. 4); Kobayashi and Okubo (1954:565, fig. 6); Nagai (loc. cit.; 1931:25). LATVIA- LITHUANIAN SSR: Mannsfield (1942: fig. 5, in part). MIDDLE EUROPE: Migula (1903:70, 71). POLAND: Raciborski (1886:161); Szwanke (1938:11, pl. 4, figs. 5-7). REPUBLIC OF CHINA: Chiou and Chang (1976: pl. 6, fig. 6); Chung (1973: figs. 2, 3); Volz et al. (1974:231, fig. 4). SWEDEN: Stjerna-Pooth (1957: figs. 2-5, photos 1-10). SWITZERLAND: Maurizio (loc. cit.; 1895a: figs. 4, 5; 1895d: 14). UNITED STATES: Beneke (1948b:68); T. W. Johnson (1956b:68, pl. 19, figs. G-I); Milanez (1966:84); Rose (1932:43, pl. 4, figs. 33-35); Rossy-Valderrama (1955:29, pl. 4, figs. 1-4). USSR: Milovtsova (1935a:34, pl. 3, fig. J1); Morochkovs’kiĭ et al. (1967:137, fig. 123); Naumov (1954:70, fig. 35). RECORDED COLLECTIONS: -- AFRICA: Alabi (1971a, b; 1973). BRITISH ISLES: M. C. Cooke (1871)(?); Trow (1895). FINLAND: Häyrén (1902-03, 1956). FRANCE: Volkonsky (1934). GERMANY: Götze (1918); Höhnk (1935a); Pringsheim (1882a); Stoll (1936). HUNGARY: Moesz (1937-38). INDIA: Dayal (1959); Dayal and Thakur Ji (1966, 1973); Mekrani (1980); Prabhuji and Srivastava (1977); G. C. Srivastava (19,67b); G. C. Srivastava and R. C. Srivastava (1975a; 1976b; 1977d, e); R. C. Srivastava and Srivastava (1978a); Mer et al. (1980). IRAQ: Al-Saadi et al. (1979). JAPAN: Hemmi and Abe (1928); Shirai et al. (1927); Suzuki (1961f). LAPLAND: Gäumann (1918). NETHERLANDS: Oudemans (1904). NEW ZEALAND: Karling (1966f). PEOPLE’S REPUBLIC OF CHINA: Ling (1948). REPUBLIC OF CHINA: Liu and Volz (1977); Sawada (1961). SOUTH AMERICA: Beneke and Rogers (1962). SWITZERLAND: Blanc (1887). UNITED STATES: Beneke and Schmitt (1961); R. L. Butler (1975)(?); W. B. Cooke and Bartsch (1959, 1960); Farr and Paterson (1974); G. C. Hughes (1959, 1962); T. W. Johnson (1956a); Kauffman (1906); Overman (1970: 19); Rossy-Valderrama (1956); Slifkin (1964); TeStrake (1958); M. W. Ward (1939); A. W. Ziegler (1958b). USSR: Dudka (1966); Meshcheryakova 1970, 1974); Mil’ko and Belyakova (1968); Yachevskim’ (1895).

544 SPECIMENS EXAMINED: -- AUSTRALIA (1), RLS. ICELAND (3), NORWAY (1), TWJ. UNITED STATES (16), WEST INDIES (1), RLS.

Achlya proliferoides Coker Saprolegniaceae, p. 115, pl. 36. 1923 (Figures 69 H, I, 70 G)

Achlya formosana Chiou and Chang, Bot. Bull. Acad. Sin. 17:47, pl. 5, figs. 1-7. 1976.

Monoecious. Mycelium moderately dense, extensive; hyphae stout, branched or slender, flexuous, and abundantly branched. Sporangia fusiform, naviculate, or cylindrical, generally slightly irregular and curved; occasionally provided with lateral discharge pores or one to a few short, cylindrical, lateral discharge tubes in addition to the terminal orifice, renewed sympodially, rarely in basipetalous succession; 26-960 x 10-52 µm. Spores monomorphic; discharge and behavior achlyoid; spore cluster not persisting at exit pore; primary spore cysts 9-12 µm in diameter. Gemmae usually very abundant; cylindrical, fusiform, often irregular, occasionally branched; terminal or intercalary, single or catenulate. Oogonia sparse or abundant; lateral, infrequently terminal or intercalary; spherical or napiform, occasionally obpyriform, infrequently oval or dolioform; frequently to rarely proliferating; (32-) 40-70 (-103) µm in diameter. Oogonial wall generally pitted; smooth on outer surface, often irregular on inner 1 1 surface. Oogonial stalks 1 – 1 /2 (-4 /2) times the diameter of the oogonium, in length; slender or moderately stout; straight or slightly curved, and often faintly irregular; extremely rarely once-coiled; unbranched. Oospores often or only occasionally not maturing or oospheres aborting; when mature, eccentric; spherical, oval, or ellipsoidal; (1-) 6-12 (-18) per oogonium, and usually not filling it; (18-) 20-25 (-35) µm in diameter; at germination forming a slender, unbranched germ hypha bearing a small, terminal, clavate or cylindrical sporangium. Antheridial branches predominantly diclinous, infrequently monoclinous with a remote origin; generally coiling prominently about hyphae which may or may not bear oogonia, but in some losing this feature with aging or subculturing; irregular, much branched; wrapping about the oogonium; persisting. Antheridial cells simple; tubular, clavate, sometimes once-branched or lobed; persisting; when long, sometimes clasping the oogonium; attached by digitate projections, rarely laterally appressed; fertilization tubes not observed.

With some reservation we are retaining Achlya proliferoides as a valid species. The one feature that separates it from all other eccentric-egged Achlyas -- the usually extensively coiled antheridial apparatus (Fig. 70 G) -- is not persistent in all cultures, and the species is then seldom recognizable as a distinct entity. Old specimens, or those carried through several subcultures, may “lose” the ability to form coiled filaments, and are then commonly identifiable as forms of A. debaryana. Achlya proliferoides is retained because not all representatives lose the coiling tendency with time or repeated transfer, and certainly when they are first isolated,

545 specimens of display the coiled antheridial hyphae very prominently. Moreover, we have never seen isolates having varying degrees of coiling (such as occurs in Aphanomyces laevis); if such filaments are present, they are frequent and prominent, and do not simply wrap sparingly by one or only a few loose turns about the hyphae and oogonial stalks. Achlya proliferoides resembles A. prolifera to some extent, but there are sufficiently prominent differences to make each recognizable as separate taxa (see A. prolifera). De Bary (1881: pl. 2, figs. 1, 2a) illustrated antheridial branches wrapping about the hyphae of A. prolifera, but in our experience with this species, this seldom occurs, and is by no means characteristic of all representatives. In a study of morphological variability in 19 isolates of Achlya flagellata (=debaryana), R. F. Elliott (1967b) gave considerable attention to the similarities between this species and A. proliferoides. The two were little different in the sizes of oogonia and oospores, and in the number of oospores. Four of the 19 specimens which she identified as A. flagellata had coiled antheridial hyphae (R. F. Elliott, 1967b:423), and in 48 subcultures from these same isolates the magnitude of coiling decreased (not eliminated) in some individuals, but remained unchanged in others. We have not examined Elliott’s material, but are inclined to view the four isolates as A. proliferoides rather than A. flagellata (=debaryana). At the same time, we recognize that the interpretation of A. proliferoides is not yet a settled matter. Achlya formosana Chiou and Chang (loc. cit.) was proposed as a new species on two characteristics that were alleged to separate it from A. proliferoides: the production of coiled antheridial filaments did not decline as the mycelium aged and such filaments also wrapped conspicuously and abundantly about the oogonia. Since some individuals of A. proliferoides do not lose the ability to form coiled filaments, and the oogonia can be enwrapped by antheridial branches, no structural basis remains for retaining A. formosana. Chiou et al. (1975) had, in fact, reported finding A. proliferoides in Taiwan, and noted that in their specimens, antheridial branch coiling decreased as the colonies aged. Descriptions of Achlya proliferoides in which antheridial filament coiling is not mentioned or illustrated are considered doubtful records of this species.

CONFIRMED RECORDS: --AFRICA: Alabi (1967: pl. 12, fig. 2). CZECHOSLOVAKIA: Cejp (1959a: 36, fig. 39). INDIA: Manoharachary (1979a: 190, pl. 1, fig. H; pl. 2, fig. I); Prabhuji (1979:72, pl. 7, fig. 6); G. C. Srivastava (1967a:285, pl. 2, figs. 8,9). IRAQ: Muhsin (1977:70, figs. A-C). JAPAN: Kobayasi and Ookubo (1952a:110, fig. 7). PHILIPPINES: Dogma (1966:25, figs. 3,4). REPUBLIC OF CHINA: Chiou and Chang (loc. cit.); Chiou et al. (1975:163, pl. 1, figs. 11-13). SOUTH AMERICA: A. L. Rogers et al. (1970:101). UNITED STATES: Beneke (1948b:67); Coker (loc. cit.); Fox and Wolf (1977a:102); T. W. Johnson (1956a:186; 1956b:63, pl. 15, fig. P; pl. 17, figs. A-D); Rose (1932:41, pl. 4, figs. 30-32); Wolf and Wolf (1941:272); A. W. Ziegler (1948b:22; 1952: 8, pl. 3, fig. 1). USSR: Logvinenko and Meshcheryakova (1971: fig. 1), WEST INDIES: T. W. Johnson (see entry, United States).

546 RECORDED COLLECTIONS: -- AFRICA: Alabi (1971a, b; 1973). INDIA: Chaudhuri and Kochhar (1935: 1431 pl. 7, figs. 12-19)(?); Chaudhuri et al. (1947: 52, fig. 24); Dayal and Thakur Ji [1965: 317, pl. 4 (?); 1966]; Manoharachary (1974); Mekrani (1980); Prabhuji and Srivastava (1977); G. C. Srivastava (1967b); R. C. Srivastava (1976); R. C. Srivastava and G. C. Srivastava (1978a). JAPAN: Hoshina et al. (1960); Kobayashi and Ôkubo (1954); Ookubo (1954); Suzuki (1961f). PHILIPPINES: Dogma (1975). SOUTH AMERICA: A. L. Rogers and Beneke (1962). UNITED STATES: Beneke and Schmitt (1961); R. L. Butler (1975: figs. 105-108); G. C. Hughes (1959, 1962); Klich (1980); Slifkin (1964); Sorenson (1962); M. W. Ward (1939); A. W. Ziegler (1958b). SPECIMENS EXAMINED: -- AUSTRALIA (1), RLS. NORWAY (1), SWEDEN (2), UNITED STATES (3), TWJ.

Achlya achlyoides (Coker and Alexander) Johnson and Seymour Mycotaxon 92:11-32, figs. 1-5. 2005 and present fig. 78 A-E

Dictyuchus achlyoides Coker and Alexander, in Coker, J. Elisha Mitchell Sci. Soc. 42:218, pl. 36. 1927. Basionym

Monoecious. Mycelium dense; hyphae slender, moderately branched. Sporangia cylindrical or fusiform, usually curved or slightly irregular; often branched or once- lobed; renewed sympodially or by cymose branching; 36-318 x 12-52 µm. Spores monomorphic; discharge and behavior of spores in primary sporangia achlyoid, in secondary ones achlyoid or dictyucoid; primary spore cysts 10-16 µm in diameter. Gemmae absent. Oogonia spherical, subspherical, or napiform; lateral, infrequently terminal; (18-) 26-32 (-48) µm in diameter, including wall ornamentations. Oogonial wall unpitted, densely or sparsely papillate, with some ornamentations cylindrical, truncate, or slightly indented. Oogonial stalks (l-) 2-4 (-11) times the diameter of the oogonium, in length; slender or stout; usually irregular, bent, or curved, infrequently sparingly coiled; unbranched or branched. Oospores eccentric; spherical; single, and occasionally nearly filling the oogonium; (16-) 22-28 (-33) µm in diameter; germination not observed. Antheridial branches, when present, androgynous or monoclinous; slender, irregular or slightly curved; unbranched or branched; persisting. Antheridial cells simple; clavate, persisting; laterally or apically appressed; fertilization tubes not observed.

Achlya achlyoides consistently produces a single oospore in each maturing papillate oogonium, and the secondary sporangia are always of two types, achlyoid and dictyucoid. The species can be identified primarily by these characteristics. Achlya pseudoachlyoides (also transferred from Dictyuchus) likewise has oogonia with only one oospore each but unlike the condition in A. achlyoides the oogonium wall is not ornamented. We are transferring Dictyuchus achlyoides (Coker and Alexander are designated as its authors by Coker and Matthews, 1937) because the primary sporangia (Fig. 78 A) are

547 achlyoid. Coker (loc. cit.) reported similar sporangia in the material he examined, and in the representatives we have recovered from bogs, the initial sporangia all released spores in an achlyoid manner. The secondary sporangia in some of our specimens are predominantly dictyucoid, but in others, secondarily produced achlyoid ones are equally frequent. Coker (loc. cit.) did not, in his very brief discussion of D. achlyoides, present arguments for assigning the species to Dictyuchus. To be sure, including D. achlyoides in Achlya distorts the concept of that genus with respect to oospore number; species of Achlya may produce oogonia with predominantly but not exclusively one oospore. In our opinion, however, the admission to Achlya of species with only one oospore per oogonium modifies generic limits far less than does retention of an achlyoid species (as to discharge pattern) in Dictyuchus. In view of this very untraditional change in the taxonomic concept of Achlya and Dictyuchus, Salvin’s (1942b) experimental work on sporangium discharge in Dictyuchus achlyoides (and Thraustotheca primoachlya), becomes particularly noteworthy (see Chapter l9). He found that achlyoid sporangia in D. achlyoides were inhibited (in abundance) more severely than dictyucoid ones when colonies were propagated in staling water. Accordingly, Salvin (1942b:103) concluded of D. achlyoides that “...the present classification is doubtless the correct one.” While it is true that he demonstrated an environmental influence on sporangium development in D. achlyoides, the experimental conditions did not eliminate achlyoid primary sporangia. The results of Salvin’s work strengthen our decision to assign D. achlyoides to Achlya, not negate it. Indeed, in several species of Achlya, the secondary sporangia are dictyucoid, thraustothecoid, or even aplanoid. The appearance of these types accompanies aging of the culture, in which complicated process the accumulation of staling products must surely play a part.

CONFIRMED RECORDS: -- UNITED STATES: Beneke (1948b:113); Coker (loc. cit.). RECORDED COLLECTIONS: -- AFRICA: Alabi (1967; 1971a, b; 1973); Salvin (1942b). SOUTH AMERICA: Upadhyay (1967). UNITED STATES: J. N. Couch (1931). SPECIMENS EXAMINED: -- AUSTRALIA (2), RLS. NORWAY (4), TWJ. UNITED STATES (1), W. C. Coker (preserved specimen).

Achlya abortiva Coker and Braxton J. Elisha Mitchell Sci. Soc. 42:143, pl. 14. 1926 (Figure 67 F-K)

Monoecious. Mycelium dense; hyphae stout, moderately branched. Sporangia naviculate or fusiform, straight or curved or occasionally bent at the apex; renewed sympodially; 105-660 x 17-35 µm. Spores monomorphic; discharge and release achlyoid, but some sporangia releasing spores through lateral discharge pores as well as the terminal one; primary spore cysts, 10-12 µm in diameter; spore cluster sometimes falling away in part from the exit orifice. Gemmae abundant; cylindrical or oval,

548 occasionally branched, lobed, or irregular, infrequently clavate; terminal or intercalary, single or catenulate. Oogonia lateral, rarely terminal; oval, fusiform, or infrequently obpyriform, occasionally angular, infrequently irregular or strongly lobed; (40-) 48-58 (-85) x (28-) 35-50(-60) µm, including wall ornamentations. Oogonial wall unpitted; provided with papillate or bullate, rarely tuberculate ornamentations, and rarely crenulate. Oogonial stalks 3 (-6) times the diameter of the oogonium, in length; curved or bent, slightly irregular in outline, rarely straight; unbranched or rarely once- branched. Oospores eccentric; spherical or ellipsoidal; 1(-8) per oogonium and generally nearly filling it; (2l-) 32-36 (-51) µm in diameter; germination not observed. Antheridial branches lacking.

Achlya abortiva as originally defined (Coker and Braxton, loc. cit.) was characterized in part by the tendency of the oospores to abort or failure of the oospheres to mature. The specimens we have examined do not exhibit this feature but are otherwise very much like Coker and Braxton described the species. In their general configuration, the oogonia of Achlya abortiva resemble those of A. crenulata (compare Figs. 67 H, I, K, and 78 F, L). Although A. abortiva lacks antheridial branches, some isolates of A. crenulata also are without this apparatus, and the two species must be distinguished from one another on additional characters. The oogonia of A. abortiva are often oval or slightly elongate, in contrast to the generally globose or obpyriform ones of A. crenulata. Most oogonia of the former have but one oospore each; 1-4 oospores commonly are found in the oogonia of the latter. The so-called forma normalis of Achlya abortiva (Coker, 1927) has no validity and is excluded from the genus (T. W. Johnson, 1956b).

CONFIRMED RECORDS: -- UNITED STATES: Coker (1927:211, pl. 28, figs. 8,9); Coker and Braxton (loc. cit.); T. W. Johnson (1956b:93, pl. 21, figs. L-P). RECORDED COLLECTIONS: -- AFRICA: Alabi (1967; 1971a, b; 1973). SPECIMENS EXAMINED: -- UNITED STATES (2), TWJ, RLS.

Achlya glomerata Coker Mycologia 4:325, pl. 79. 1912 (Figure 79 A-C)

Monoecious. Mycelium dense, limited or moderately extensive; hyphae slender, moderately branched near periphery of colony. Sporangia sparse; cylindrical, fusiform, or clavate; straight, curved, or slightly irregular; renewed sympodially, infrequently in a cymose manner; 88-211 x 17-27 µm. Spores monomorphic; discharge and behavior achlyoid, infrequently aplanoid; primary spore cysts 9-10 µm in diameter. Gemmae sparse, cylindrical, fusiform, clavate, or irregular; terminal or intercalary, single or catenulate. Oogonia lateral, infrequently terminal; spherical or subspherical; (28-) 30-40 (-55) µm in diameter, including wall ornamentations. Oogonial wall unpitted; papillate or tuberculate, occasionally crenulate, or ornamentations truncate or long-conical; very

549 rarely smooth. Oogonial stalks 1-6 times the diameter of the oogonium, in length; stout; usually irregular or twisted, branched or unbranched; often or only occasionally forming a glomerulus. Oospores eccentric; spherical or compressed from mutual pressure; 1 (-2) per oogonium, but usually not filling it; (14-) 19-22 (-28) µm in diameter; at germination forming a slender unbranched germ hypha producing a small, terminal sporangium. Antheridial branches usually absent; when present, androgynous or monoclinous, very rarely diclinous; short, slender, irregular or twisted; unbranched or branched; persisting. Antheridial cells simple; tubular or clavate; persisting; apically appressed; fertilization tubes not observed.

Achlya glomerata can be recognized by its small, ornamented oogonia, single (usually), eccentric oospore, and the glomerulate oogonial stalks (Fig. 79 A, B). The oogonium wall projections of Coker’s species often resemble those of A. abortiva, but that species lacks antheridial branches. Achlya glomerata is distinguished readily from other species with ornamented oogonia and predominantly one or two oospores by reason of its oospore structure. In A. stellata, A. spinosa, and A. ornata, for example, the oospores are never eccentric. Like A. glomerata, A. crenulata has eccentric oospores but its oogonia are larger and more sparsely ornamented than are those of the former. Achlya crenulata also consistently has more numerous oospores than A. glomerata. The close resemblance of the oogonia of Achlya glomerata (Fig. 79 B, C) to those of A. achlyoides (Fig. 70 C, E; formerly in Dictyuchus is at once apparent, but there are strong differences between these two taxa. Achlya glomerata lacks dictyucoid sporangia but produces glomeruli; A. achlyoides produces the former but not the latter. Cejp’s report (1934:190, pl. 1, fig. 13; pl. 2, figs. 1-4) of Achlya glomerata is rejected (but included in records of unidentified species). He observed only the asexual elements of the fungus he identified as this species.

CONFIRMED RECORDS: -- CZECHOSLOVAKIA: Cejp (1957: fig. 119, 3; 1959a:130, figs. 35-37). POLAND: Zaborowska (1965:46). UNITED STATES: Coker (loc. cit. 1923:133, pl. 48); T. W. Johnson (1965b:91, pl. 3, figs. C-G); A. W. Ziegler (1948b:23, pl. 5, figs. 1, 2; 1952: 9, pl. 4, fig. 4). RECORDED COLLECTIONS: -- BRITISH ISLES: Hunter (1975); R. E. Roberts (1963). GERMANY: Höhnk (1935a). SOUTH AMERICA: Upadhyay (1967). UNITED STATES: R. L. Butler (1975)(?); Coker (1927); J. N. Couch (1927); Farr and Paterson (1974); J. V. Harvey (1930); Höhnk (1935a); T. W. Johnson (1956a); V. D. Matthews (1927, 19.35); Scott et al. (1963). SPECIMENS EXAMINED: -- UNITED STATES (2), TWJ; W. C. Coker (preserved type).

Achlya crenulata Ziegler Mycologia 40:336, figs. 1-10. 1948. (Figure 78 F-M)

550 Achlya tuberculata Ziegler, Mycologia 42:658, figs. 1-15. 1950.

Monoecious. Mycelium extensive, dense at colony periphery; hyphae slender, moderately branched. Sporangia fusiform, occasionally naviculate or cylindrical; renewed sympodially, occasionally in basipetalous succession; 91-810 x 15-52 µm. Spores monomorphic; discharge and behavior achlyoid; primary spore cysts 9-11 µm in diameter. Gemmae sparse or abundant; cylindrical, fusiform, obpyriform, or irregular and branched; terminal or intercalary, single or catenulate. Oogonia lateral, rarely or infrequently terminal; spherical or obpyriform, occasionally oval, angular, or subglobose, rarely lobed or irregular (20-) 40-60 (-l08) µm in diameter, inclusive of wall projections. Oogonial wall unpitted, sparsely pitted, or showing thin areas at the apex of some projections; crenulate, tuberculate, or papillate, or sometimes provided with 1 lobed, flared, or cordate ornamentations. Oogonial stalks ( /4 -) 2 (-4) times the diameter of the oogonium, in length; stout; straight, curved, bent, or irregular; isodiametric or tapering slightly toward the base; unbranched, very rarely once- or twice-branched. Oospores may or may not mature; when mature, eccentric; spherical or ellipsoidal; 1-4 (-16) per oogonium, and usually filling it; (14-) 20-30 (-40) µm in diameter; at germination forming a slender, slightly irregular germ hypha bearing a small, terminal, clavate sporangium. Antheridial branches usually sparse; when present, monoclinous or diclinous; slender, of variable length; unbranched or branched; persisting. Antheridial cells simple, tubular or clavate, infrequently irregular; persisting; laterally or occasionally apically appressed; fertilization tubes present, not persisting.

The majority of the oogonia of Achlya crenulata are crenulate or densely papillate (Fig. 78 J, K), and thus the species is readily distinguished from A. lobata with its stout, prominent, and often lobed ornamentations (see A. lobata Fig. 73 H, J). In A. lobata, moreover, a single, large oospore is found in most oogonia while two or three are usual in A. crenulata. The antheridial branches are abundant in the former species, but sparse in the latter. It has been reported (A. W. Ziegler and Gilpin, 1954) that A. lobata can be separated from A. crenulata by reason of its generally larger oospores, but we find oospore size to be too variable in some representatives of A. crenulata to be useful taxonomically. An occasional oogonium of Achlya abortiva (Fig. 67 G, H, J) has a general aspect similar to that of A. crenulata (Fig. 78 F, G, I), but the two can be recognized as separate taxa by reliance on other characters. There usually are more oospores in the oogonia of A. crenulata than A. abortiva, and, of course, Ziegler’s species has some antheridial branches, but none is formed in A. abortiva. The merger of Achlya tuberculata with A. crenulata is justified by T. W. Johnson (1956b), and need not be repeated here. We concur with that decision.

CONFIRMED RECORDS: -- INDIA: Dayal and Thakur Ji (1969:173, figs. 17-24): REPUBLIC OF CHINA: Volz et al. (1974:231, fig. 3). SOUTH AMERICA: Upadhyay

551 (1967:52, 53, pl. 3, figs. 1-4). UNITED STATES: R. L. Butler (1975: figs. 141-144); T. W. Johnson (1956b:95, pl. 22); A. W. Ziegler (loc. cit.; 1948b:24, pl. 5, fig. 3; 1952:10, pl. 4, figs. 6, 7). RECORDED COLLECTIONS: --INDIA: Thakur Ji (1967). REPUBLIC OF CHINA: Liu and Volz (1977). UNITED STATES: G. C. Hughes (1959, 1962); Schmitt (1967); TeStrake (1958); A. W. Ziegler (1950, 1958b). SPECIMENS EXAMINED: -- UNITED STATES (8) RLS, and A. W. Ziegler (preserved type).

Achlya subterranea Coker and Braxton J. Elisha Mitchell Sci. Soc. 42:141, pl. 13. 1926 (Figure 64 B-G)

Monoecious. Mycelium dense, limited; hyphae moderately stout, sparingly to frequently branched. Sporangia sparse or abundant, cylindrical or narrowly fusiform; straight, curved, or slightly irregular; sometimes provided with lateral discharge pores in addition to the terminal ones; renewed sympodially or in basipetalous succession; 287-625 x 16-38 µm. Spores monomorphic or dimorphic; discharge and behavior achlyoid from some sporangia, but in other sporangia a number of primary spores are flagellated and escape in a saprolegnoid fashion; other sporangia releasing spores in a thraustothecoid fashion; spore cluster occasionally imperfectly formed, or in part breaking up, and falling away from the exit pore; infrequently some spores released, others remaining in the sporangium; primary spore cysts 9-11 µm in diameter. Gemmae ovoid, clavate, cylindrical, or broadly ellipsoidal; terminal or intercalary, single or catenulate; disarticulating. Oogonia lateral, rarely intercalary; spherical, obpyriform, or noticeably angular to irregular; (30-) 58-78 (-86) µm in diameter, including truncate, slightly raised wall projections. Oogonial wall pitted, or pitted only under region of antheridial cell attachment; a low or inconspicuous tuberculate projection, truncate terminally, usually present where antheridial cell contacts the oogonial wall; smooth or with one to a very few narrow or broad, short or elongate, 1 3 1 1 cylindrical projections. Oogonial stalks ( /4-) /4 - 1 /4 (-2 /2) times the diameter of the oogonium, in length; stout; straight or curved, slightly irregular; unbranched. Oospores eccentric; spherical, oval, or broadly ellipsoidal; (1-) 3-6 (-12) per oogonium, and usually filling it or nearly so; (13-) 22-28 (-37) µm in diameter; germination not observed. Antheridial branches, when present, monoclinous or diclinous; slender, often irregular, twisted, or contorted, unbranched or sparingly branched; persisting. Antheridial cells simple; clavate or cylindrical, usually curved or noticeably bent; persisting; apically appressed; fertilization tubes sometimes produced but not persisting.

Hasty scrutiny of gross cultures is likely to result in overlooking this species. The oogonia and antheridial apparatus of Achlya subterranea are not far removed in general appearance from some variants of A. debaryana. The singular feature that

552 identifies A. subterranea is the production of a short, truncate projection of the oogonial wall at its juncture with the antheridial cell (Fig. 64 C, F, G). These projections -- they are by no means prominently displayed in many oogonia -- on occasion impart an angular appearance to the oogonium (Fig. 64 B). In part, the species also can be recognized by the generally short and stout oogonial stalks (Fig. 64 B, D, G), but this is not a dependable characteristic by itself. In the specimens of Achlya subterranea that we have examined, and in that seen earlier by T. W. Johnson (1956b), the sporangia were very sparse and either had discharged or were immature. Accordingly, we have not been able to confirm for this species the variable nature of zoospore behavior at their release (Coker and Braxton loc. cit.). If studies of additional A. subterranea specimens show the protoachlyoid behavior to prevail among the primary sporangia, the species should be assigned to Protoachlya. Its retention in Achlya is provisional. It would be highly speculative to include as a record of Achlya subterranea the report by Bhatt and Manandhar (1973:229, fig. la, b), for the stylized illustrations do not depict the characteristic raised areas on the oogonial wall. These authors described the antheridial branches as androgynous (as well as diclinous), but illustrate only a monoclinous one. The oospore type in the specimen from Nepal was not mentioned.

CONFIRMED RECORDS: -- UNITED STATES: Coker and Braxton (loc. cit.); T. W. Johnson (1956b:60, pl. 12, figs. A, B). RECORDED COLLECTIONS : -- AFRICA: Alabi (1967, 1971b, 1973). UNITED STATES: Coker (1927); J. V. Harvey (1930); Sparrow (1952b). SPECIMENS EXAMINED: -- UNITED STATES (5), TWJ, RLS.

Achlya lobata Ziegler and Gilpin Mycologia 46:647, figs. 1-10. 1954 (Figures 73 H-L, 75 A)

Monoecious. Mycelium dense; hyphae slender, branched. Sporangia cylindrical; straight or sinuous; renewed sympodially, infrequently in a basipetalous manner; 111- 211 x 22-30 µm. Spores monomorphic; discharge and behavior achlyoid; primary spore cysts 9-12 µm in diameter. Gemmae abundant; cylindrical, narrowly obpyriform, and sometimes slightly irregular; terminal one tapering distally; terminal and intercalary. Oogonia terminal or lateral, spherical, obpyriform, subspherical, or broadly oval; (31-) 45-55 (-69) µm in diameter inclusive of wall ornamentations. Oogonial wall unpitted; densely marked with bilobed, cordate, or broad, stout, short tubercles, occasionally with scattered papillae. Oogonial stalks 1-2 times the diameter of the oogonium, in length; stout, straight or curved; unbranched. Oospores eccentric; spherical, or ellipsoidal or pyramidal from mutual pressure; 1-2 (-4) per oogonium, and usually filling it; (24-) 28- 30 (-33) µm in diameter; germination not observed. Antheridial branches abundant; diclinous; slender, irregular; unbranched or sparingly branched; not persisting. Antheridial cells simple; irregularly bulbous, clavate, or cylindrical; sometimes lobed or

553 branched; persisting; laterally appressed or when lobed occasionally apically attached; fertilization tubes not observed.

Achlya lobata is easily identified by the dense stout, prominent, bilobed, truncate, or cordate wall extensions (Fig 73 H, J). See A. crenulata for an account of the structural similarities and differences between it and A. lobata. Certain culture manipulations with Achlya lobata were performed by A. W. Ziegler and Gilpin (loc. cit.) in an attempt to determine something of its morphological variability. While pH and temperature levels had measurable influences on whether or not A. lobata would form the sexual apparatus, these same factors were ineffectual in modifying such structural elements as the nature or prominence of the oogonial wall ornamentations and antheridial branch origin.

CONFIRMED RECORD: -- UNITED STATES: A. W. Ziegler and Gilpin (loc. cit). RECORDED COLLECTIONS: --UNITED STATES: A. W. Ziegler (1958b). SPECIMENS EXAMINED: -- UNITED STATES (1), WEST INDIES (1), RLS.

Achlya primoachlya (Coker and Couch) Johnson and Seymour Mycotaxon 92:11-32, figs. 26-30. 2005, and present fig. 75 B-F

Thraustotheca primoachlya Coker and Couch, J. Elisha Mitchell Sci. Soc. 40:198, p1s. 39, 40. 1924. Basionym

Monoecious. Mycelium dense; hyphae stout, frequently branched. Sporangia very abundant, cylindrical, clavate, fusiform, or naviculate, often irregular or curved, rarely branched; renewed sympodially or cymosely; 90-188 x 12-39 µm; achlyoid ones may deliquesce shortly after spore release. Spores monomorphic; discharge and behavior achlyoid from primary sporangia, thraustothecoid or achlyoid from secondary ones; primary spore cysts 9-12 µm in diameter. Gemmae lacking. Oogonia lateral, rarely terminal; spherical or oval; (28-) 55-68 (-84) µm in diameter, including wall ornamentations. Oogonial wall unpitted, but thin at apex of some wall projections; provided sparsely or densely with conspicuous papillae that are rounded or nearly 3 1 truncate at the apex, or with crenulate protuberances. Oogonial stalks ( /4-) l –1 /2 (- 3) times the diameter of the oogonium, in length; stout, straight or curved, but not recurved; only very slightly irregular; unbranched. Oospores eccentric; spherical; (1-) 4- 8 (-20) per oogonium, and generally not filling it, (16-) 20-24 (-29) µm in diameter; at germination forming a short, slender germ hypha, usually penetrating the oogonial wall through a projection, and bearing a small, terminal, subclavate sporangium of the achlyoid or thraustothecoid type, or forming a germ tube only or endogenous spores without first developing a sporangium. Antheridial branches sparse; androgynous or monoclinous, but often not attached to an oogonium; slender and usually irregular or somewhat twisted and gnarled; short or long; branched or unbranched; not persisting.

554 Antheridial cells simple; tubular or clavate; persistent; laterally appressed; fertilization tubes not observed.

Both in the original description and discussion of Thraustotheca primoachlya the primary sporangia were said to be achlyoid in the manner of discharge (Coker and Couch loc. cit.), and this is the case with our specimens. Spore release from secondary sporangia, on the other hand, is thraustothecoid or achlyoid, with the latter becoming less frequent as the colony ages. Moreover, when the oospores germinate, the resulting sporangia also are either achlyoid or thraustothecoid in the release of spores. A rather peculiar aspect of the primary achlyoid sporangia is that they may deliquesce (in some individuals) shortly after the spores are released. Since the primary sporangia are consistently achlyoid in their behavior at dehiscence, we are transferring Thraustotheca primoachlya to Achlya. In this connection it may be noted that B. R. Green and Dick (1972) judged that their determinations of DNA base pair compositions (GC percentages) were supportive of an assignment of T. primoachlya to Achlya. Salvin (1942b) experimented with Thraustotheca primoachlya in a study of the effect of culture conditions on the spore release pattern in certain watermolds (see Chapter 19). He found that regardless of the particular culture environment, the mycelium of the isolates produced only achlyoid sporangia at first. Later, as the culture water became fouler, the frequency of achlyoid discharge declined, and thraustothecoid release predominated or occurred exclusively. We suggest that these findings at least do no violence to our decision to transfer T. primoachlya to Achlya. In their account of Thraustotheca primoachlya Coker and Couch (1924:197) suggested that the sporangial behavior in this species could be “... considered as the ‘youth form’...”, and pointed to “...Achlya as the ancestor of Thraustotheca.” Sorenson (1962) thought that T. primoachlya might be an intermediate species (see A. dubia). The configuration of the oogonial wall in Achlya primoachlya is strikingly similar to that in A. recurva (Figs.75 D, and 79 D, E). The apex of most of the wall ornamentations in both species is thin and truncate. Antheridial branch origin in the two is also similar as is the predominant oospore number and size in some specimens. However, there are contrasting known characters of the two species that seem sufficiently distinct to warrant their separation. In general, the truncate wall ornamentations in A. recurva are more numerous and more prominent (Fig. 79 D, E) than those in A. primoachlya (Fig. 75 C, F). On the other hand, the oogonia of the latter are more likely to be papillate (without also being thin-walled at the apex) than are those of the former. With the single exception of an Iceland variant, A. recurva has oogonia slightly smaller (predominantly) than those of A. primoachlya, but the range of diameter in most forms of the two is nearly the same. We have not found in any specimens of A. primoachlya the strongly recurved oogonial stalks characteristic of A. recurva, and in the latter, so far as we are aware, thraustothecoid sporangia are not produced (nor have they been reported by others).

555 Latham (1935), who first provided a comprehensive description of Achlya recurva recognized its close resemblance to T. primoachlya, but believed the two could be distinguished from one another on several structural grounds. He observed, for example, that the wall protuberances in A. recurva were longer and more numerous than in T. primoachlya, and were symmetrically arranged. We find that there is, to be sure, a degree of asymmetry in the ornamentations of A. primoachlya (Fig. 75 F). In sum, we maintain Achlya primoachlya and A. recurva provisionally as separate species. Nevertheless, the strong similarity between the taxa in general oogonial configuration prompts us to add that the matter of their identity is not yet settled. Too few specimens have been collected and studied to allow a firm conclusion in this regard.

CONFIRMED RECORDS: -- UNITED STATES: Beneke (1948b:126); R. L. Butler (1975: figs. 161-164); Coker and Couch (loc. cit.); A. W. Ziegler (1948b:26, pl. 6, fig. 1; 1952:15, pl, 6, fig. 5). RECORDED COLLECTIONS: -- AFRICA: Fajola et al. (1979). UNITED STATES: Coker (1927); Coker and Braxton (1926); G. C. Hughes (1959, 1962); T. W. Johnson (1956a); V. D. Matthews (1927); J. R. Raper (1950b); Salvin (1942b); A. W. Ziegler (1958b). SPECIMENS EXAMINED: -- UNITED STATES (3), RLS, TWJ. MWD (1).

Achlya recurva Cornu Ann. Sci. Nat. Bot. (5e sér.) 15:22. 1872 (Figure 79 D-H)

Monoecious. Mycelium diffuse but dense at periphery of colony, moderately extensive; hyphae slender, moderately branched. Sporangia clavate or fusiform, infrequently cylindrical; straight, curved, or slightly irregular, apex occasionally attenuated into a long, narrow discharge tube; renewed sympodially, rarely in basipetalous succession; 81-820 x 14-53 µm. Spores monomorphic; discharge and behavior achlyoid, occasionally aplanoid; primary spore cysts 9-12 µm in diameter. Gemmae rare; when formed, obovate to short-cylindrical; generally single and terminal or intercalary. Oogonia lateral, rarely terminal, very rarely intercalary; spherical, infrequently subglobose, very rarely dolioform or irregular; (28-) 35-50 (-l24) µm in diameter, exclusive of wall ornamentations. Oogonial wall unpitted; densely or sparsely provided with conical projections, truncate and thin-walled at the apex. 1 3 1 Oogonial stalks ( /2-) /4 – 1 (-3 /2) times the diameter of the oogonium, in length; stout; straight, curved, or often recurved; often irregular, but only rarely twisted or once- coiled; unbranched, or infrequently with one or two short, irregular or papillate branches. Oospores eccentric; spherical, ellipsoidal or flattened adjacent to neighboring ones; (1-) 4-8 (-48) per oogonium, and generally filling it; (l4-) 20-26 (-38) µm in diameter; at germination producing a slender, irregular, unbranched or once-branched germ hypha bearing a small, terminal, clavate sporangium. Antheridial branches

556 androgynous, rarely monoclinous, very rarely diclinous; short, rarely long, usually curved or bent, and irregular; rarely branched; persisting. Antheridial cells simple; clavate or cylindrical, infrequently irregular, often bent or curved; persisting; laterally or apically appressed, seldom attached in an inconspicuous, digitate fashion; fertilization tubes present, persisting or not.

Cornu’s (loc. cit.) description of Achlya recurva was quite brief, and not accompanied by any illustrations. It is to Latham (1935) that an accountable description (and figures) can be traced. His concept of Cornu’s species has prevailed, and the species is at once recognizable by its conspicuous, truncate wall markings (Fig. 79 D, G). Almost all such projections are thin-walled at the apex. Achlya recurva can be confused with A. primoachlya (Fig. 75 B-F) particularly if specimens are examined hastily. We have discussed in our treatment of the latter species the chief differences between these two taxa. Variants of Achlya recurva have been reported. A prominent one was that recovered by T. W. Johnson (1974b) on three occasions from soils in Iceland. These individuals were marked by the production of noticeably larger oogonia (predominantly 65-88 µm in diameter, excluding the wall ornamentations), and oospores (generally 25-28 µm in diameter) also larger than are usually met with in this species. The oogonia usually contained 10-12 oospores (median 70%). There were no differences between the Iceland forms and the “typical” A. recurva in the general aspect of the sexual apparatus and the nature of the wall ornamentations. Milanez and Beneke (1968) collected specimens of A. recurva in which the oospores generally were few in number (2-4 per oogonium), and large (25-35 µm in diameter). The Achlya sp. described and illustrated by Overman (1970) clearly was A. recurva, although she maintained that it was not. Like the watermold reported by Milanez and Beneke, the one found by Overman had a smaller number of generally larger oospores than had been described for A. recurva. The Achlya recurvata [sic] isolated by Karling (1976) was only identified as this species with reservation. The watermold -- under the name A. recurva -- illustrated by Forbes (1935a: pl. 8, fig. 4) evidently produced conical or spiny rather than truncate ornamentations. Precisely what species she had cannot now be determined, but perhaps it occupied a position near A. oligacantha (T. W. Johnson, 1956b: 90).

CONFIRMED RECORDS: -- BRITISH ISLES: Dick (1969b: pl. 2, figs. 3,4). CZECHOSLOVAKIA: Cejp (1959a:128, fig. 34). DENMARK: A. Lund (1934:27, fig. lla). FRANCE: Cornu (loc. cit.). GERMANY: Minden (1912:543). ICELAND: T. W. Johnson (1974b:13, figs. 94-96). INDIA: Manoharachary (1979a:191, pl. 2, fig. J; 1979b:198, pl, 1, fig. 4). JAPAN: Kobayasi and Konno (1971a:11, fig. 3 K-M). POLAND: Zaborowska (1965:46, fig, 8). REPUBLIC OF CHINA: Chiou et al. (1975:162, pl. 1, fig. 6). SOUTH AMERICA: Milanez (1970:28, fig. 6-11). UNITED STATES: R. L. Butler (1975: figs. 137-140); Latham (1935:183, pl. 52); Milanez (1966:86, pl. 6); Milanez and Beneke (1968:16, pl. 1, figs. 8, 9); Overman (1970:24, pl. 3); A. W. Ziegler (1941: pls. 1-3; 1948b:24,

557 pl. 5, fig. 4; 1952:10, pl. 4, fig. 5). USSR: Morochkovs’kĭĭ et al. (1967:135, fig. 121); Shkorbatov (1927:78). RECORDED COLLECTIONS: --AFRICA: Karling (1976) (?). BRITISH ISLES: Cook and Forbes (1933); Dick (1963, 1966); Dick and Newby (1961); Forbes (1935b); Hartog (1889b, 1895). INDIA: S. B. Saksena and Rajagopalan (1958: 13, figs. 29-34)(?); Manoharachary (1974). UNITED STATES: G. C. Hughes (1959, 1962); T. W. Johnson (1956a); J. R. Raper (1950b); Scott (1960b); M. W. Ward (1939); A. W. Ziegler (1958b). USSR: Mil’ko and Belyakova (1968). SPECIMENS EXAMINED: -- AUSTRALIA (1), AFRICA (1), OCEANIA (2), RLS. ICELAND (5), TWJ. UNITED STATES (4), TWJ, RLS.

Achlya heterosexualis Whiffen-Barksdale In Barksdale, Mycologia 57:493, figs. 9-19. 1965 (Figure 76 E-G)

Dioecious or monoecious. Mycelium diffuse; hyphae moderately stout, moderately branched; capable of self- or interspecific conjugation. Sporangia fusiform or cylindrical; renewed sympodially; sometimes with a lateral exit orifice; 142-309 x 23- 42 µm. Spores monomorphic; discharge and behavior achlyoid; primary spore cysts 9- 11 µm in diameter. Gemmae abundant; fusiform, cylindrical, or slightly irregular; often disarticulating; terminal or intercalary, single or catenulate. Oogonia lateral or terminal, rarely intercalary; spherical, obpyriform, or subglobose; (66-) 80-130 (-152) µm in diameter. Oogonial wall pitted; smooth. Oogonial stalks 1-3 times the diameter of the oogonium, in length; stout; sometimes tapering slightly toward the base; unbranched. Oospores not always maturing, but eccentric when mature; spherical; 3-18 per oogonium, and filling it or not; (18-) 20-26 (-39) µm in diameter; at germination forming a germ hypha. Antheridial branches in self-conjugating thallus monoclinous, diclinous, or androgynous; arising from another thallus in cross-conjugating mating; slender, unbranched or branched; persisting. Antheridial cells simple, rarely compound; tubular or faintly clavate, sometimes irregular or twisted; long and occasionally clasping the oogonium; persisting; laterally appressed, infrequently attached in a digitate fashion; fertilization tubes unknown. (Adapted in part from Barksdale (loc. cit.).

As we have seen only one isolate of this species – that one being highly refractory toward sexual reproduction – our comments on the taxon necessarily are limited. The sexual apparatus in self-conjugating representatives of Achlya heterosexualis has a general aspect much like that of A. americana or A. debaryana. In cross-conjugating specimens -- if we judge correctly from the illustrations provided by Barksdale (loc. cit.) -- A. heterosexualis is indistinguishable from A. ambisexualis. The difference between these two species seems to be primarily (if not solely) in their sexual reactions. In Achlya heterosexualis (Barksdale loc. cit., p. 498) only the antheridial branches are cross-induced. The oogonia are self-induced, but function either with cross- or self- induced antheridial filaments. All interthallic (interspecific) matings in A. heterosexualis

558 terminate with the attraction of antheridial branches, hence the species reacts sexually in much the same manner as some homothallic species (Barksdale, 1960). In A. ambisexualis, on the contrary, both antheridia and oogonia can be cross-induced. Not all isolates (identified as “strains” by Barksdale loc. cit.) of Achlya heterosexualis are equally responsive sexually. Some are strongly self-conjugative and produce abundant oogonia and antheridial hyphae. Others rarely self-conjugate. In this connection it may be recalled that isolate B4 identified by Barksdale in 1960 as Achlya klebsiana subsequently was considered a strain of A. heterosexualis (1962b). Strain Bl of A. bisexualis also was later (Barksdale, 1965) assigned to A. heterosexualis. Barksdale (loc. cit.) believed that the spherical gemmae of Achlya bisexualis distinguished it from A. heterosexualis. In her 1962(b) account of A. bisexualis, she reported that self-conjugating thalli of that species produced only diclinous antheridial branches. This characteristic contrasts sharply with the condition in self-conjugating isolates of A. heterosexualis where monoclinous and androgynous branches also are developed. Bits and pieces of circumstantial evidence gleaned from the literature suggest that Achlya heterosexualis had been described earlier under the name A. regularis (Coker and Leitner, 1938). The gemmae of A. regularis were characterized as being cylindrical, and they may be of this shape in Whiffen-Barksdale’s species. Coker and Leitner (1938: 311) reported that their species was persistently “… heterothallic, but with weak homothallic tendencies...”, and it is known that some isolates of A. heterosexualis are comparably “sexed.” When specimens of A. regularis were kept apart from compatible mates, the colonies did not produce the sexual apparatus until they had aged considerably (Coker and Leitner, 1938:312). Our isolates of A. heterosexualis -- denied companionship -- also developed oogonia and antheridial hyphae after some delay, and then only very sparsely. Achlya regularis is an illegitimate name, and we are excluding it on this basis. Were more known in a definitive way of A. heterosexualis we would be inclined to list A. regularis with that species simply to emphasize the obvious similarity between the two taxa. Until the mating systems in the eccentric-egged species of Achlya are thoroughly understood, their taxonomy remains unsettled. There is ample evidence that some individuals of the cross-conjugating species and others of the self-conjugating ones are sexually compatible. The genetics of the zygotic product from intra- and interspecific matings is not known, however, and only when these products of the many possible matings are propagated and analyzed will it be possible to treat the taxonomy of these fungi in a meaningful fashion. Morphological evidence is readily amassed; genetic evidence is not at hand. Nonetheless, it seems to us reasonable to predict that some presently recognized monoecious (homothallic) species in Achlya will prove to be sexual variants of dioecious taxa.

CONFIRMED RECORD: -- UNITED STATES Barksdale (loc. cit.). RECORDED COLLECTION: -- UNITED STATES: Barksdale (1960).

559 SPECIMENS EXAMINED: -- Subculture of holotype, ATCC; Centraalbureau (1); MWD (2).

Achlya ambisexualis J. R. Raper Amer. J. Bot. 26:639, figs. 1-15, 17-27. 1939 (Figures 70 E, F, 71 A)

Achlya ambisexualis var. abjointa J. R. Raper, Amer. J. Bot. 26:640, figs. 7-10. 1939. Achlya ambisexualis var. gracilis J. R. Raper ibid., p. 641, figs. 11-15. 1939.

Dioecious, but capable of gynandromixis, cross-conjugation, and some degree of interspecific compatibility. Mycelium of oogonial thallus dense, extensive; hyphae stout, branched. Sporangia clavate or fusiform; renewed sympodially; 210-500 x 21-48 µm. Gemmae abundant; cylindrical, occasionally irregular; terminal or intercalary, single or catenulate; occasionally disarticulating. Mycelium of antheridial thallus diffuse, extensive; hyphae moderately stout, branched. Sporangia sparse, cylindrical or fusiform; renewed sympodially; 160-590 x 16-41 µm. Gemmae sparse, cylindrical, occasionally fusiform, rarely clavate. Spores monomorphic in both thalli; discharge and behavior achlyoid; primary spore cysts 9-14 µm in diameter; spore cluster persisting at exit orifice or disintegrating in part. Oogonia lateral or terminal, very rarely intercalary; spherical or obpyriform; (33-) 50-85 (-110) µm in diameter. Oogonial wall pitted under 1 the region of antheridial cell attachment; smooth. Oogonial stalks ( /2-) 1 (-4) times the diameter of the oogonium, in length; stout, straight, curved, or slightly irregular; often tapering toward the base; unbranched or extremely rarely branched. Oospores almost always maturing; eccentric; spherical; (1-) l0-l8 (-36) per oogonium, and generally filling it; (14-) 18-24 (-38) µm in diameter; germination not observed. Antheridial branches arising from one (“male”); long, slender, irregular, and abundantly branched; often wrapping about the oogonium and its attendant hypha; persisting. Antheridial cells simple or compound; tubular or clavate, branched or unbranched; persisting; attached in a digitate fashion or laterally; fertilization tubes not observed.

This dioecious species resembles Achlya bisexualis in general configuration of the sexual apparatus. Three morphological differences, however, are important in the identification of specimens of A. ambisexualis. In Raper’s species the oospheres nearly always mature into oospores that usually fill the oogonial cavity. Oosphere maturation is decidedly uncommon in A. bisexualis, and these cells seldom occupy the oogonial cavity fully. Differences between the two species in gemma shape vary among the strains or forms and thus are not as reliable as once believed. The characters separating A. ambisexualis from A. heterosexualis are treated in the discussion of the latter species. See also A. regularis and A. heteromorpha in the section on excluded taxa. Achlya ambisexualis has been used widely in a variety of nontaxonomic studies (Liles, 1969; Tontz, 1969; Thomas, 1966; Bret, 1971, 1972a; Dodd et al., 1975; Horgen et al.,

560 1976, among others). It has of course been the subject of much research-on hormonal (pheromone), control of sexual reproduction (Chapter 21). Some interthallic (interspecific sexual reactions, exhibited by strains of Achlya ambisexualis were uncovered by Barksdale (1960). She demonstrated that some alleged homothallic species (A. caroliniana, A. klebsiana, and A. flagellata, among others) reacted sexually with mating strains of A. ambisexualis in two-member cultures. For example, a strain of A. ambisexualis behaved as a female when paired with A. flagellata (=debaryana); the latter formed antheridial initials. Achlya ambisexualis (but not A. bisexualis) functioned as a female to one strain of A. americana that produced antheridial initials in response to the presence of the heterothallic (dioecious) species. Some isolates of Achlya ambisexualis and A. bisexualis also were compatible, Barksdale (1960: fig. 1) noted that some matings resulted in the development of oogonial initials (no stages beyond) but others completed the sexual process with the formation of oospores. Largely because the oospores developed in successful matings have not been germinated and their products analyzed, genetic information applicable to the taxonomy of Achlya ambisexualis is wanting. The compatibility of strains of some monoecious species of Achlya with A. ambisexualis (and A. bisexualis) supports our decision to merge A. flagellata, A. klebsiana, A. conspicua into one taxon on morphological grounds. Individual specimens identified with these species react positively to the presence of the heterothallic ones (Barksdale, 1960: fig. 2). Positive identification of Achlya ambisexualis depends upon properly mating cultures so that the oogonial and oospore characteristics can be determined. Some of the records of collection of this species are of specimens that seem to have been identified solely on features of the sporangia and shape of the gemmae; such records must be held suspect.

CONFIRMED RECORDS: -- BRITISH ISLES: J. R. Raper (loc. cit.). CANADA: Barksdale (1965:497, figs. 1-8). IRAQ: Muhsin (1977:61, figs. A-C). REPUBLIC OF CHINA: Chiou et al. (1975:160, pl. 1, figs. 3, 4). SOUTH AMERICA: Beneke and Rogers (1962:185; 1970:55); A. L. Rogers et al. (1970:99). UNITED STATES: Barksdale (loc. cit.); Beneke (1948b:83); Milanez (1966: 73); Milanez and Beneke (1968:15); J. R. Raper (loc. cit.). RECORDED COLLECTIONS: -- AFRICA: Nolard-Tintigner (1973, 1974). BRITISH ISLES: Hunter (1975); J. R. Raper (1950b). INDIA: Nolard-Tintigner (1973, 1974). PHILIPPINES: Dogma (1966: 50, fig. 10; no matings attempted)(?). REPUBLIC OF CHINA: Liu and Volz (1977). UNITED STATES: Barksdale (1960); W. B. Cooke and Bartsch (1959, 1960); J. R. Raper (1950b); TeStrake (1958). USSR: Logvinenko and Meshcheryakova (1971). SPECIMENS EXAMINED: -- BRITISH ISLES & UNITED STATES, J. R. Raper (strains E87, 734).

Achlya bisexualis Coker and A. Couch In Coker, J. Elisha Mitchell Sci. Soc. 42:207, pl. 27. 1927

561 (Figure 70 A-D)

Dioecious, but capable of self-conjugation and some degree of interspecific compatibility. Mycelium of oogonial thallus limited or extensive, and dense near substratum; hyphae slender, branched. Sporangia fusiform, infrequently cylindrical; renewed sympodially or in basipetalous succession; 110-400 x 25-45 µm. Gemmae abundant; dolioform, spherical, subspherical, obovate, obpyriform, or short-cylindrical; thin-walled or thick-walled; terminal or intercalary, single or catenulate. Mycelium of antheridial thallus extensive, diffuse; hyphae stout, sparingly or moderately branched. Sporangia fusiform, infrequently cylindrical; renewed sympodially or in basipetalous succession; 280-980 x 26-70 µm. Gemmae abundant; predominantly cylindrical, occasionally irregular, in some strains spherical, obpyriform, or obovate. Spores monomorphic in both mating types; discharge and behavior achlyoid, spore cluster persisting or falling away in part from exit orifice; primary spore cysts 9-12 µm in diameter. Oogonia lateral, occasionally terminal, rarely intercalary; spherical or obpyriform, occasionally oval, rarely dolioform; (35-) 60-75 (-130) µm in diameter. Oogonial wall pitted under region of antheridial cell attachment; smooth on outer 1 surface, but occasionally irregular on inner surface. Oogonial stalks (1-) 1 /2-2 (-10) times the diameter of the oogonium, in length; stout; straight, slightly curved or irregular; occasionally once-branched; slightly flared distally on some oogonia. Oospores infrequently or rarely maturing, but all may mature in any one oogonium; eccentric; spherical, occasionally ovoid; (2-) 5-10 (-28) per oogonium, and not filling it; (l6-) 22-26 (-40) µm in diameter; at germination forming a slender germ hypha which may or may not bear a terminal sporangium. Antheridial branches arising from one thallus, or, in self-conjugating strains in a diclinous fashion; long, slender, irregular, abundantly branched; often wrapping about the oogonium and its attendant hypha; persisting. Antheridial cells simple or compound, tubular or clavate; branched or unbranched; persisting; attached laterally or in a digitate fashion; fertilization tubes not observed.

The structural differences among Achlya bisexualis, A. ambisexualis, and A. heterosexualis are treated in the accounts of these latter two species. See also comments on the excluded taxa A. regularis and A. heteromorpha. Barksdale (1962b) emphasized the importance of gemma shape in the identification of Achlya bisexualis. She proposed that the name bisexualis be applied only to those cross-conjugating Achlyas provided with spherical gemmae. According to J. R. Raper (1936), the spherical hyphal segments of A. bisexualis differed from the cylindrical ones produced by the same species in having thicker walls and being capable of converting to oogonia. He divided strains of A. bisexualis into three groups: female with both spherical and cylindrical gemmae, hermaphroditic female with both gemmae types, and male with cylindrical ones only. Barksdale (1960) mated ten strains producing the spherical type of gemmae, and found five to behave as females and five as males. In a later study (Barksdale, 1962b) of 34 strains producing spherical gemmae,

562 15 reacted as males, 15 as females, and 4 males responded as females in certain mating strain combinations. The most exacting taxonomic analysis of Achlya bisexualis was that published by Barksdale in 1962(b). Like Nagai earlier (1931:18, 19), she believed that the unidentified Achlya species recorded by Emoto (1923), Coker (1923:137), Weston (1917), and Humphrey (1893:83) were forms of A. bisexualis. Barksdale reduced A. flexuosa Nagai to synonymy with A. bisexualis, pointing to their similarities in antheridial branch origin, infrequency of oogonia, failure of oospheres to mature, and oospore diameter. Nagai (1931), however, did not find A. flexuosa to be a cross-mating species, and one must assume that the fungus he had was monoecious. In any event, Howard et al. (1970) chose not to follow Barksdale (1962b) and fixed Nagai’s species as a synonym of A. prolifera, largely on the same structural features that Barksdale had enumerated in combining A. flexuosa with A. bisexualis. Our opinion (Howard et al., 1970) that the affinities of Nagai’s species are with A. prolifera has not changed, and removing A. flexuosa from equal status with A. bisexualis preserves the integrity of the latter. It may be recalled at this point that isolate B1 of A. bisexualis collected by Barksdale (1960) was later (1965) identified by her as a strain of A. heterosexualis. Achlya bisexualis has been used widely in biochemical, ultrastructural, and genetic studies, and has even been implicated in saprolegniosis (Chapter 29). Barksdale (1960) demonstrated that representatives of A. bisexualis could be mated successfully with A. ambisexualis and with certain homothallic (monoecious) species as well. Some interthallic conjugations involving A. bisexualis induced only antheridial branch initial formation, but in other matings with this species mature oospores were produced. Some aspects of the enzymology of calcium-induced sporangium formation in A. bisexualis were published by O’Day and Horgen (1974), and Horgen and O’Day (1975). Darnaud (1972a, b) and Montant and Darnaud (1971) inquired into certain experimentally-induced morphological changes in the hyphae of this species. Dargent (1977) studied the growth pattern in A. bisexualis while Dargent and Denisse (1976) examined the subcellular structure of the hyphae in relation to acid phosphatase activity. The topic of hormonal (pheromone) control of sexuality in A. bisexualis has been widely explored, with details of the chemistry and biochemistry of sex cell inducement coming from studies by D. M. Green et al. (1971), leading to the synthesis of antheridiol, structural characterization of the oogoniols (McMorris and White 1977; McMorris, 1978a, b; McMorris et al., 1978), and the discovery by R. H. White and McMorris (1978) of the biosynthetic pathways operating in the conversion of oogoniols from fucosterol (see Chapter 21).

CONFIRMED RECORDS: -- JAPAN: Barksdale (see entry, United States). NETHERLANDS: Beverwijk (1948:243, fig. 7). PEOPLE’S REPUBLICS OF CHINA: Er (1973:38). PHILIPPINES: Dogma (1966:41, figs. 8 9). RUMANIA: Toma (1971:13, pl. 3; pl. 4, fig. 10). SOUTH AMERICA: Beneke and Rogers (1962:185); Beroqui de Martinez (1970:113, figs. 2 B-F, 3 H-J); A. L. Rogers et al. (1970:100). SWEDEN: Beverwijk (see entry, Netherlands). UNITED STATES: Barksdale (1962b:704 et sqq., figs. 1-14); Beneke

563 (1948b:82); Coker (loc. cit.); T. W. Johnson (1956b:51, pl. 9, figs. A-D, I-L); Milanez (1966:76); Milanez and Beneke (1968:15); O’Bier (1960:31, pl. 1, fig. E; pl. 5); J. R. Raper (1936:277, 282, 283; pl. 22, figs. 1-5, 8-14; pl. 23; pl. 24, figs. 27-29, 33, 34); Wolf [1944:29; reported collection of a homothallic (monoecious) strain]. WEST INDIES: Volz and Beneke (1972:2). RECORDED COLLECTIONS: -- BRITISH ISLES: J. R. Raper (1950b); ICELAND: T. W. Johnson (1974b). INDIA: S. B. Saksena and Rajagopolan (1958: 16, figs. 44-46. Very doubtful; no sexual apparatus observed). ITALY: D. M. Green et al., (1971). PHILIPPINES: Dogma (1975). REPUBLIC OF CHINA: Liu and Volz (1977). RUMANIA: Toma (1970). UNITED STATES; Barksdale (1960); Beneke and Schmitt (1961); R. L. Butler (1975)(?); Coker and Leitner (1938); W. B. Cooke and Bartsch (1960); Crane and Vermillion (1966); T. W. Johnson (1956a); Klich (1980); Lasure and Griffin (1974); J. R. Raper (1950b); Scott and O’Bier (1962); Slifkin (1964); Te Strake (1958); Wolf (1937b). USSR: Mil’ko and Zakharova (1976). SPECIMENS EXAMINED: -- ICELAND (1), TWJ. UNITED STATES (3) TWJ, E. S. Beneke, J. R. Raper. Centraalbureau (1).

Achlya sp.

Records of unidentified Achlyas associated with diseased (but living) fish or with fish eggs are marked by an asterisk (*). The names of the invaded fish species are given in the papers cited. Some unidentified isolates of Achlya that have been reported very likely were mating strains of dioecious species.

AFRICA: El-Hissy (1974); Karling (1976); Nolard-Tintigner (1973: fig. 17; 1974*); Sansome and Harris (1962). AUSTRALIA: Crooks (1937: -214, fig. 2A, B; possibly a female mating strain). BELGIUM: Nolard-Tintigner (see entry, Africa). BRITISH ISLES: Apinis (1964); Barnes and Melville (1932); V. G. Collins and Willoughby (1962); Dick (1966); H. J. Fletcher (1979); P. H. Gregory (1951); Hartog (1895); Newton (1971); O’Sullivan (1965); Park (1972a); Pickering and Willoughby (1977*); Willoughby (1962; 1965; 1970*: pl. 2, figs. a, e; 1978*); Willoughby and Collins (1966); Willoughby and Pickering (1977*). CANADA: Booth (1971; possibly Aphanomyces stellatus); Chong (1973*); Dick (1970, 1971c); Duff (1929*); Maestres (1977); Neish (1976: pl. 4, fig. 3; 1977). CENTRAL AMERICA: Liles (1969); Weston (1941). CZECHOSLOVAKIA: Cejp [1934:190, pl. 1, figs. 11 and 12 (as A. apiculata) pl. 1, fig. 13 and pl. 2, figs. 1-4 (as A. glomerata); 1959a]. DENMARK: A. Lund (1934: fig. 12; 1978); Petersen (1903, 1909a, 19, 10). FRANCE: Guilliermond (1922); Moreau and Moreau (1948). GERMANY: de Bary (1888); Bock (1956); Höhnk (1956a, 1958); Minden (1916); F. Müller (1911); Remy (1950); Rudolph (1912); Schlösser (1929:538). HONG KONG: Yung and Stenton (1964). ICELAND: T. W. Johnson (1974b*). INDIA: Bhargava (1943); Bhargava et al. (1971 *) Chaudhuri and Kochhar (1935:149, pl. 12, figs. 12-23; same reported in Chaudhuri et al., 1947: 54, 55, figs. 25-28); Dayal and Thakur Ji (1965); Jha et al. (1977:60*); Mekrani (1980*); Mer et al. (1980); Nolard-Tintigner (1974*); Prabhuji (1979); S. B. Saksena and

564 Rajagopalan (1958: 14, 16, figs. 41-46); Sarbhoy (1964); A. K. Srivastava (1978a, 1979*); R. C. Srivastava (1976*); R. C. Srivastava and G. C. Srivastava (1978a*); Thakur Ji and Dayal (1966). IRAQ: Muhsin (1977:81). JAPAN: Emoto (1923); Indoh (1941:89, fig. 5); Okane (1967, 1978); Suzuki (1960a, c, d, g; 1961b, d, h-1; 1962b, d); Suzuki and Hatakeyama (1960, 1961); Suzuki and Nimura (1960; 1961d, e); Suzuki and Tatsuno (1964, 1965a); Suzuki et al. (1960, 1961). NEPAL: S. C. Singh (1968a: 12, fig. 2). PEOPLE'S REPUBLIC OF CHINA: Wei et al. (1955). PHILIPPINES: Dogma (1975). REPUBLIC OF CHINA: Chung (1973*); Volz et al. (1974: fig. 5). SOUTH AMERICA: Beneke and Rogers (1970:58); Milanez (1968:102), Möller (1901). SWITZERLAND: Maurizio (1897b*); Tiesenhausen (1912:289). UNITED STATES: Armstrong (1955, 1956); Bandoni et al. (1975); Barksdale (1960); Bartsch and Wolf (1938); Beneke and Schmitt (1961); M. C. Carlson (1920); Clausz (1970, 1974); Coker (1923:137, pl. 50, figs. 1-4); W. B. Cooke (1976a); W. B. Cooke and Bartsch (1959, 1960); W. B. Cooke and Matsuura (1969); Farr and Paterson (1974); Fox and Wolf (1977a); Fuller and Poyton (1964); Gaertner and Sparrow (1966); H. E. Gregory and Wentworth (1937; said to be a “fish mold” parasitic on Daphnia sp.); Griffin (1966); J. V. Harvey (1927b, c; 1952); Hidalgo-Quimio (1965); Ho (1975c); G. L. Hoffman (1949*); G. C. Hughes (1959, 1962); Humphrey (1893: pl. 15, figs. 19,20); T. W. Johnson (1950b); Kanouse (1925); Karling (1977); Kauffman (1908); Klich (1980); Kuehn (1960); S. W. T. Law and Burton (1976a, b); Milanez (1966: 89); Monsma (1936*); Padgett (1978a); Poitras (1955); Rajagopalan (1963: 119, fig. 3 A-D); J. R. Raper (1936: 278, pl. 22, figs. 6,7; pl. 24, figs. 30-32, 35; 1950b); Rooney and McKnight (1972); Rose (1932: 43, pl. 4, figs. 33-35; provisionally identified as A. prolifera); Rossy- Valderrama (1955); Salvin (1940); Schmitt and Beneke (1962); Scott (1962); Scott and Warren (1964*); Shipman (1979); Sorenson (1962: pl. 1, figs. D, F); Sparrow (1965); TeStrake (1958); Weston (1917: 356 et seq., pl. 18; describes resistant spores alleged not to be gemmae); W. N. Tiffney (1936: 21; 1939b:148; both reported on shell of Chelydra serpentina); Vishniac and Nigrelli (1957*); M. W. Ward (1939); Wolf and Wolf (1941). USSR: Mikheeva (1969); Mil’ko and Zakharova (1976). WEST INDIES: Coker (1927); J. N. Couch (1927); Volz and Beneke (1972). YUGOSLAVIA: Ristanović (1970a).

IMPERFECTLY KNOWN SPECIES OF ACHLYA

Achlya aquatica Dayal and Thakur Ji Mycopathol. Mycol. Appl. 38:169, figs. 1-6. 1969

Monoecious. Mycelium moderately extensive, diffuse; hyphae stout, moderately or sparingly branched. Sporangia fusiform to clavate, occasionally cylindrical; straight, curved, or slightly irregular; renewed sympodially, infrequently in a basipetalous manner; 86-421 x 15-61 µm. Spores monomorphic; discharge and behavior achlyoid, infrequently aplanoid; spore cluster usually falling away from exit orifice; primary spore cysts 7-16 µm in diameter. Gemmae sparse; cylindrical or broadly clavate to long- obpyriform; terminal or intercalary, single or catenulate. Oogonial lateral, infrequently terminal, very rarely sessile; spherical, subspherical, or irregular to lobed, or having one

565 to a few large, conspicuous, broadly cylindrical to broadly conical wall projections; immature ones capable of proliferating; (29-) 40-54 (-79) µm in diameter, including wall ornamentations. Oogonial wall pitted under region of attachment of antheridial cells; smooth or with one to a few scattered, large, long-conic to long-cylindric or papillate to bullate wall ornamentations; wall sometimes crenulate in part. Oogonial stalks short or long; generally stout; straight, curved, or bent, isodiametric or tapering toward the base from a flared distal end; unbranched. Oospores eccentric; spherical or broadly oval; (1-) 3-5 (-12) per oogonium, and usually not filling it; (14-) 22 (-25) µm in diameter; germination not observed. Antheridial branches monoclinous, occasionally androgynous, infrequently diclinous; somewhat irregular or twisted; unbranched to abundantly branched; persisting. Antheridial cells simple; large, irregular, lobed, or tubular to clavate; persisting; laterally appressed; fertilization tubes not observed.

The foregoing description of Achlya aquatica (the name first appeared in Thakur Ji’s paper of 1967) was compiled in part from that prepared by Dayal and Thakur Ji (loc. cit.) and in part from characterization of a subculture of the type specimen (Centraalbureau, Baarn). As originally described and illustrated, A. aquatica properly could be considered new to science. The available subculture of the type, however, proved to contain more than one species. From the subculture we isolated an unidentified Pythium, a nonsexual Dictyuchus, and two species of Achlya. There were slender, branched, conspicuously coiled hyphal branches in the subculture of the type, and these were sometimes associated with oogonial initials. On isolation, hyphae with these coiled branches yield colonies nearly identical to one of the variants (Series IX) of A. americana described by T. W. Johnson and Seymour (1974a). As in the case of the specimens of A. americana, the fungus isolated from the subculture of A. aquatica lost the coiled branches through repeated transfers. The second Achlya isolated produced only a few oogonial initials (and some attendant antheridial branches lacking antheridial cells); these did not mature either in water culture, on cornmeal agar, or on Seymour’s (1970) medium. The initials were irregular for the most part, a few showing some conical or cylindrical projections, and others being somewhat elongate and slightly constricted equatorially. The general aspect of the oogonial initials of this second Achlya isolated from the subculture of the type is indeed that of some of the oogonia illustrated for A. aquatica (Dayal and Thakur Ji, loc. cit.). Although Achlya aquatica appears to be a valid species, additional specimens must be recovered and studied in axenic culture to determine whether or not the rather characteristic oogonia are indeed a stable feature. It is in the meantime best treated as an imperfectly known taxon.

CONFIRMED RECORD: -- INDIA: Dayal and Thakur Ji (loc. cit.). RECORDED COLLECTIONS: -- INDIA: Thakur Ji (1967).

566 SPECIMENS EXAMINED: -- INDIA (1), subculture of type, Centraalbureau, Baarn.

Achlya hoferi Harz Allg. Fischerei-Zeitung 31:367, 1 unnumbered fig. 1906

Monoecious. Mycelium luxuriant; hyphae stout or slender; abundantly branched. Sporangia cylindrical or clavate; renewed sympodially; 30-600 x 5-20 µm. Spore discharge and behavior achlyoid. Gemmae unknown. Oogonia lateral or terminal; oval, broadly dolioform, or nearly spherical; 75-180 x 40-60 µm (excluding papillae?). Oogonial wall provided with papillae or long-conical projections rounded at the apex. Oogonial stalks long, slender, or short and stout. Oospores spherical; (1-) 20 (-30) per oogonium, and filling it; 20-30 µm in diameter. Antheridial branches lacking. (Adapted from Harz, loc. cit.)

In his treatment of Achlya hoferi T. W. Johnson (1956b:105) was unable to reach a decision as to its validity; we share that indecision. The overall configuration of the oogonia of A. hoferi conveys an impression of the ornamented forms of A. androgyna, if one may judge from the stylized illustrations prepared by Harz. Earlier, T. W. Johnson (1956b:106) recognized the similarity of A. hoferi to A. treleaseana (=androgyna) as did Howard and his associates (1970:68). Tempting as it is to merge A. hoferi with A. androgyna we are not doing so for lack of supporting evidence. If it is assumed that Harz was quite accurate in depicting Achlya hoferi, there is reason to retain his taxon pending analysis of additional specimens (should any be recovered). The oogonia of A. hoferi occur on very slender branches, quite unlike the stout ones associated with vigorous mycelium of A. androgyna. Harz’s material of A. hoferi evidently produced sporangia abundantly -- the antithesis of A. androgyna -- and intercalary oogonia were either rare or absent. Achlya hoferi lacked antheridial branches, but this is a condition we have seen (Howard et al., 1970:168) in A. androgyna. Achlya hoferi is retained provisionally, even though it is certainly incompletely known. The oospore type must be discovered before a decision as to its disposition can be made.

CONFIRMED RECORD: -- GERMANY: Harz (loc. cit.); recovered from mirror carp (living).

Achlya pinnulata Harvey J. Elisha Mitchell Sci. Soc. 58:28, pl. 4, fig. 8; pl. 5; pl. 7, fig. 1. 1942

Monoecious. Mycelium moderately extensive, dense. Sporangia long, narrow- cylindrical, fusiform, or naviculate; sometimes provided with one to several lateral exit tubes in addition to the apical orifice; unbranched or once-branched; straight, curved, often somewhat irregular; renewed sympodially or cymosely; 128-1080 x 48-52 µm.

567 Spores monomorphic; discharge and behavior achlyoid, occasionally aplanoid; discharge through more than one pore or exit tube in some sporangia; spore cluster occasionally falling away from exit pore; primary spore cysts 10.8-12.6 µm in diameter. Gemmae sparse or abundant; cylindrical, fusiform, or irregular; terminal. Oogonia lateral, seldom sessile, single or catenulate; spherical, sometimes obpyriform or napiform, rarely irregularly lobed; commonly 54-63 µm in diameter. Oogonial wall pitted under region of attachment of antheridial cells, rarely at other places as well; smooth. Oogonial stalks about as long as the diameter of the oogonium; straight, curved, or irregular; unbranched or branched. Oospores eccentric; spherical or, in some lobed oogonia, ellipsoidal or broadly oval; (1-) 4-12 (-35) per oogonium, and usually not filling it; mostly 21.6-23.6 µm in diameter; germination not observed(?). Antheridial branches diclinous or monoclinous with a remote origin; slender, very irregular, often several times branched near the oogonia; apparently persisting. Antheridial cells small, clavate; laterally appressed. (Adapted from J. V. Harvey, loc. cit.)

This is an illegitimate species (having been described without a Latin diagnosis) and should technically be excluded from the genus. However, T. W. Johnson (1956b) chose to retain the taxon among those imperfectly known or of doubtful affinities, and we are following that decision here. A few of the illustrations of Achlya pinnulata (J. V. Harvey, loc. cit., pl. 4, fig. 8) are suggestive of some forms of A. debaryana. Other figures, however, do not recall this or any other taxon in the eccentric-egged group. Three characteristics, primarily, indicate that Achlya pinnulata may be a valid species. First, the sessile oogonia are rather distinctive in their position immediately below obpyriform ones on the same stalk (J. V. Harvey, loc. cit., pl. 5, figs. 6, 7). Secondly, some oogonia are strikingly irregular because of one or more lobes, “...the whole unit suggesting a cluster of grapefruit...” as J. V. Harvey (loc. cit., p. 29) described them. Thirdly, A. pinnulata appears to produce lateral oogonia in a catenulate fashion, although how frequently such a configuration obtained in Harvey’s specimens is not known. Should the foregoing combination of characters prove to be consistent in any additional specimens that may be recovered, Harvey’s species might well be validated. To be sure, the lobed condition of some oogonia brings to mind Achlya intricata. However, in that species, such oogonia do not consist of several closely clustered, spherical segments each containing 1-2 oospores as seems to be characteristic (J. V. Harvey, loc. cit., pl. 5, fig. 4) of A. pinnulata.

CONFIRMED RECORD: -- UNITED STATES: J. V. Harvey (loc. cit.). RECORDED COLLECTION: -- USSR: Naumova (1955:134, fig. 2)(?).

EXCLUDED TAXA

Achlya abortiva f. normalis Coker and Braxton

568 In Coker, J. Elisha Mitchell Sci. Soc. 42:209, 210, pl. 28, figs. 1-7. 1927

When hyphae or gemmae of the contorted form of Achlya abortiva were transferred to media, Coker (1927:211) reported, the resulting colonies were of this normal form. Thus, the form was an entity produced in culture, and should not be accorded any taxonomic status. The authors of the form normalis were not designated in the publication in which the original description occurred (Coker, 1927). The names of the authors were added by Coker and Matthews, in 1937. Thus, T. W. Johnson (1956b) erred in attributing this form to Coker alone.

Achlya apiculata var. forbesiana Cejp Oomycetes I, Flora ČSR, Ser. B, Part 2, p. 172. 1959

An illegitimate name; see discussion of Achlya apiculata.

Achlya benekei Furtado Rickia 2:122, figs. 1-10. 1965

Transferred to Protoachlya

Achlya californica Harvey J. Elisha Mitchell Sci. Soc. 58:31, pl. 6, figs. 1-3; pl. 7, fig. 2. 1942

An illegitimate name. The specimens described under this name were merely variants of Achlya debaryana [T. W. Johnson had earlier (1974b:8) reached this conclusion, but equated Harvey’s species with A. flagellata].

Achlya contorta Cornu Ann. Sci. Nat. Bot. (5e Sér.) 15:25, pl. 1, figs. 9-15. 1872

The only feature of this species emphasized by Cornu (loc. cit.) is the contorted nature of the oogonial stalks. The illustrations seem to center on the rather extensively developed system of fertilization tubes. Achlya contorta is too meagerly described to retain. Beneke (1948b) in describing a new Achlya used the name Achlya contorta. In a publication in the same year (1948a), the name was changed to A. intricata.

Achlya cornuta Archer Quart. J. Microscop. Sci. (N. S.) 7:126, pl. 6, figs. 2-6. 1867

On page 125 of his account of this species Archer (loc. cit.) referred to the presence of “...empty mother cells...” of spermatozoids. Because he found these cells to

569 be identical to those figured by Pringsheim (1860) for A. dioica, Archer chose not to illustrate them. Both T. W. Johnson (1956b) and Dick (1960b) directed attention to the fact that A. cornuta was based on infected specimens and therefore was to be excluded. Johnson retained A. cornuta in the category of imperfectly known species, but that decision is not defensible. As Dick (1960b) so persuasively pointed out, the sexual apparatus of Achlya cornuta is indistinguishable from that of A. stellata. The A. cornuta described and figured by Humphrey (1893:126, pl. 20, figs. 103, 104) was without doubt based on a specimen of A. stellata. There is no way of being certain if either M. C. Cooke (1871) or Höhnk (1935a) -- who report collecting A. cornuta actually had Archer’s species (or, what is more likely, were observing A. stellata).

Achlya dioica Pringsheim Jahrb. Wiss. Bot. 2:211 et sqq., pl. 23, figs. 1-5. 1860

Pringsheim (loc. cit.) applied the name Achlya dioica to a watermold obviously infected by a chytridiaceous fungus resembling superficially a Woronina. In 1939, J. N. Couch demonstrated that Pringsheim’s species was a chytrid, and named it Pringsheimiella dioica. Later, Mullins (1961) erected the genus Dictyomorpha to accommodate Couch’s species since the name Pringsheimiella was preempted. In a paper published in 1864, M. J. Berkeley reported Achlya dioica from England, and M. C. Cooke (1871) included reference to this same species in his listing of British fungi. The one illustration which Berkeley (1864: fig. 14) drew from material at hand shows a hypha infested by a Rozella or a Woronina. As had Pringsheim for Saprolegnia dioica, Berkeley contended that the uniflagellate motile cells associated with A. dioica were the male sperm that brought about fertilization.

Achlya dubia var. pigmenta Chaudhuri and Kochhar Proc. Indian Acad. Sci. (Sect. B) 2:147, pl. 11, figs. 1-12. 1935

This variety is too ill-defined to recognize and retain, and, indeed, its characterization is contradictory at least in one point. Information on such critical diagnostic features (important in the identification of the variety) as oogonium wall pitting, oospore structure, and discharge and behavior of spores is lacking. In the original description, the antheridial branch origin was said to be diclinous or only rarely androgynous. This conflicts with the statement in the discussion by Chaudhuri and Kochhar (loc. cit., p. 147) to the effect that a distinctive feature of the variety was its “...constantly occurring diclinous antheridia.” Chaudhuri et al. (1947:40) repeated this discrepancy. The authors of the variety seem to have placed considerable taxonomic weight on the pigmentation of the oogonial wall but ignored the fact that Coker (1923: 136) described the oogonium wall in the species A. dubia as “...distinctly yellow-brown.” Since nothing is known of the spore behavior in Achlya dubia var. pigmenta, it certainly cannot remain as a variety of A. dubia. Acting conservatively, T. W. Johnson

570 (1956b:58, 59, 108) thought that the variety was probably a form of A. klebsiana yet retained the name in the category of taxa of doubtful affinities. We see no reason to support that decision, when it is so obvious that the variety cannot be identified as it has been described.

Achlya ferax (Kützing) Duncan Proc. Roy. Soc. London 25:253, pl. 7, figs. 36-38, 40-42. 1876

Duncan did not recognize any distinction between members of Saprolegnia and Achlya, and simply renamed S. ferax (Gruith.) Thuret.

Achlya Hähneliana Cejp Bull. Int. Acad. Tchéque Sci. 1934:192, pl. 1, figs. 17-23; pl. 3, figs. 3, 4. 1934

As T. W. Johnson (1956b) pointed out, the name Achlya Hähneliana was based on parasitized specimens in mixed material, and therefore has no validity. Some of the measurements given in the description of this “species” suggest that Cejp had observed a Dictyuchus rather than an Achlya. Cejp (1959a) listed A. Hähneliana as a possible synonym of Wolf’s (1941) A. rodrigueziana.

Achlya heteromorpha Harvey J. Elisha Mitchell Sci. Soc. 58:32, pl. 7, figs. 3-7. 1942.

This species has been excluded by T. W. Johnson (1956b) from the genus because the name was illegitimately published. At the same time, however, he concluded that the specimens (collected in Death Valley, California, at approximately 54 meters below sea level) on which Harvey erected the species were representatives of Achlya ambisexualis. In her comment on Achlya bisexualis Barksdale (1962b:710) suggested that on the basis of the structure of its gemmae the oogonial plant of A. heteromorpha could be assigned to A. bisexualis, and the antheridial member of Harvey’s species then would be accommodated in A. ambisexualis or “...some other species.” Upadhyay’s (1967) record of Achlya heteromorpha from Brazil must be treated as doubtful. He made no mention of a dioecious sexual condition in his cultures.

Achlya hypogyna Coker and Pemberton Bot. Gaz. (Crawfordsville) 45:194, figs. 1-6. 1908

Transferred to Protoachlya.

Achlya intermedia Bail Amtl. Ber.Versamml. Deutsch. Naturf. Aerzte, Königsberg 35:257. 1860

571 Bail’s species is not an Achlya. Coker (1923) considered it to be the same as Saprolegnia monoica Pringsheim, a species synonymous with S. ferax (Seymour, 1970).

Achlya kamatti Date J. Univ. Poona Sci. & Technol. Sect., No. 42, p. 79, fig. 1. 1972

The status of Achlya kamatti cannot be evaluated from either the description or illustrations, and the preserved type specimens we have seen are not particularly helpful. Oospore type was not described, and the preserved material has lost the disposition of the oil reserve. The concentric nature of the oospores referred to by Date (loc. cit.) describes the position of these cells in the center of the oogonial cavity. Some oogonia in the type specimen are infected by a monocentric, epiendobiotic chytrid -- very likely Rhizophydium carpophilum (Zopf) Fischer -- and it seems possible that Date mistook sporangia of the chytrid for at least some of the antheridia of the watermold. The preserved mycelium of Achlya kamatti bears uninfected oogonia as well, and these are clearly seen to be enwrapped by antheridial branches, a feature which Date failed to describe or illustrate. The large, broadly obpyriform oogonia, on noticeably stout stalks, which predominate in the type material of A. kamatti, recall very strikingly the specimens we have seen of A. irregularis and we suspect that this is the proper identification of Date’s fungus. It is impossible to determine from the preserved type the nature of the critical characters needed to identify the fungus which Date recovered. As the specimens are infected, the species must be excluded.

Achlya leucosperma Cornu Ann. Sci. Nat. Bot. (5e Sér.) 15:24. 1872

This species cannot be recognized on the basis of the limited characterization provided by Cornu. The fact that the oospores were alleged to be white is a worthless feature; the oospores and hyphae of all watermolds appear milky-white in reflected light.

Achlya nowickii Raciborski Rozpr. Spraw. Posiedzeń Wydz. Mat.-Przyr. Akad. Umiejętn. 14:166, pl. 3. 1886

According to Raciborski (loc. cit.) this species produced sex cells like those in Achlya prolifera, in which case the oogonia would be smooth-walled, and would be accompanied by diclinous antheridial branches. As neither of these features is referred to in the description of A. nowickii, Raciborski’s specimens obviously were incorrectly interpreted. Perhaps, as one figure (upper left), on plate 3 of Raciborski’s paper suggests, he had collected a specimen of A. androgyna. Walentowicz (1885) reported Achlya nowickii as occurring together with Saprolegnia monoica (=ferax) on carp. The descriptive matter he provided is too scanty to be of use in defining the Achlya. According to A. Fischer (1892:490), A. nowickii was near

572 A. spinosa. Migula’s (1903:71) description, like Walentowicz’s, adds nothing to the characterization of Raciborski’s species.

Achlya oidiifera Horn Ann. Mycol. 2:231, fig. 20. 1904

Although Horn (loc. cit.) provided a description of this species, information on the taxonomically critical features of the structure of the fungus are lacking. Because the sporangia were neither described nor illustrated, assignment of Horn’s fungus to a genus is impossible. When colonies of Achlya oidiifera were cultured on flies and on 1% agar (Horn, loc. cit.), the hyphae formed Oidium-like segments that disarticulated. Migula’s (1903) description of Horn’s species is merely a compilation and adds nothing to the circumscription.

Achlya pacifica Harvey J. Elisha Mitchell Sci. Soc. 58:27, pl. 4, figs. 1-7. 1942

The name was illegitimately published, and is excluded on that basis. Harvey’s specimens likely were variants of Achlya caroliniana, if one may judge from the illustrations and descriptive matter.

Achlya paradoxa Coker Mycologia 6:285, pl. 146. 1914

Because the primary spores of this species were flagellated at discharge, unlike the condition prevailing in Achlya species, Coker (1923) transferred A. paradoxa to Protoachlya.

Achlya penetrans Duncan Proc. Roy. Soc. London 25:249 et sqq., pls. 5; 6; 7, figs. 33-35, 39, 43-61. 1876

It was Humphrey’s (1893) notion that Duncan’s species was a siphonaceous alga, and Kawaguchi (1942:105) included it among the “parasitic” green algae. There is a very noticeable resemblance of some of the illustrations provided by Kawaguchi (1942: figs. 8, 9) to those published by Duncan (1876: pl. 7, figs. 39, 44). Duncan illustrated (1876b: pl. 7, figs. 48, 49, 53, 55, 61) what he believed were oospores and zoospores of A. penetrans, but the resemblance to actual structures is at best superficial.

Achlya prolifera Pringsheim Nova Acta Phys.-Med. Acad. Caes. Leop.-Carol. German. Nat. Cur., 23:399 et sqq., pls. 46-50. 1851.

573 As Seymour (1970) pointed out, Pringsheim (loc. cit.) was dealing with Saprolegnia ferax, not Achlya prolifera. It is in this 1851 account that for the first time sporogenesis in S. ferax was described fully.

Achlya regularis Coker and Leitner J. Elisha Mitchell Sci. Soc. 54:311, pl. 38. 1938

The name is illegitimately published (T. W. Johnson, 1956b), and therefore must be excluded. The specimens on which Achlya regularis was erected were believed by T. W. Johnson (1956b:52, 53) to represent A. bisexualis. Barksdale (1962b), however, proposed that only those cross-conjugating forms of Achlya with spherical gemmae (both male and female strains) should be identified as A. bisexualis. Acceptance of this proposal would of course then exclude the strains designated under the binomial A. regularis. Coker and Leitner (1938:311) concluded that A. regularis belonged “...to the bisexualis-imperfecta-flagellata-Klebsiana group.” Achlya regularis was described as being persistently “...heterothallic, but with weak homothallic tendencies.” This being the case, a later counterpart to A. regularis seems to be A. heterosexualis (Barksdale, 1965).

Achlya variabilis Hine Amer. Quart. Microscop. J. 1:140. 1878

Achlya variabilis was a name proposed to encompass three entities: A. racemosa sensu Hildebrand, an unnamed variety of Hildebrand’s species, and A. lignicola. The name has no validity, as it was not accompanied by any formal description.

Achlya sp. Schlösser Planta 8:538. 1929

The description of this unnamed watermold lacks the critical details necessary for a judgment as to its true identity. Schlösser simply named the specimens “kleine Achlya sp., n. sp.” Achlya sp. Viégas and Teixeira Bragantia 3:228, pls. 6, 7. 1943

The omission of important descriptive characteristics in the circumscription of the Brazilian specimens makes it impossible to identify this unnamed species, and to place it properly among the Achlyas. The general configuration of the sexual apparatus suggests Achlya prolifera, but other characteristics such as oospore size and number (presumably only one per oogonium, if one may judge from the illustrations) exclude Achlya sp. as a representative of A. prolifera.

Achlya sp. Kobayasi and Konno J. Jap. Bot. 46:11, fig. 4A-E. 1971

574

Sporangia were not described for this unnamed species, although gemmae were said to function as achlyoid sporangia. The one figure (Kobayasi and Konno, 1971a: fig. 4D) showing endogenous spores in a “gemma” indicates that those spores had encysted within the functional hyphal segment. If this behavior pattern were a constant feature, the fungus would be excluded from Achlya. The oospore structure is simply defined (Kobayasi and Konno, 1971a:11) as “…finely granulous”. Until the disposition of the refractive bodies in the oospores is discovered, the species cannot be assigned to any group of Achlya. The papillate nature of the oogonia suggests that perhaps the authors had collected A. spinosa or A. stellata.

Achlya 478 Reed In Thesis, Eastern Illinois Univ., Charleston, p. 142, fig. 65. 1973.

According to Reed, the fungus identified by this number was to be described as a new species. No such description subsequently appeared. From the brief account (in a key to species) given by Reed, the specimens resembled Achlya recurva (sensu Latham), but the wall projections of the oogonia were often rounded (they are truncate in A. recurva), and were not thin apically. The oogonia of Achlya 478 were described as being smaller than those of A. recurva.

Palaeachlya perforans Duncan Quart. J. Geol. Soc. 32:210, pl. 16, fig. 12. 1976

Duncan (loc. cit.) considered this entophytic species to be an alga and classified it “…amongst the unicellular type in the neighbourhood of Achlya…” Whatever else the tubules described by Duncan might have been, they certainly were not achlyoid in any sense.

575