Joum. Hattori Bot. Lab. No. 62: 281-288 (June 1987)

PHAEOCEROS LAEVIS (L.) PROSK. AND P. CAROLINIANUS (MICHX.) PROSK., THEIR SPORES

GABRIELA G. HAsSEL DE MENENDEZl

ABSTRACT. Descriptions and scanning electron micrographs of the lectotype of Anthoceros lae vis L., the type species of Phaeoceros Prosk., and of the type of A. carolinianus Michx. are presented to illustrate the characteristics which demonstrate that they belong to different species. Photographs of the type specimens are provided, together with details of the spores of "Anthoceros JaWs majoribus Dill ." , which are identical to those of Phaeoceros carolinianus (Michx.) Prosk.

I NTRODUCTION In order to promote further studies on the Anthocerotopsida, the author (1984) began a study of the two Linnean species remaining in the class, Anthoceros punctatus L. and A. laevis L., in which the excellent diagnostic characters of the spores were emphasized. In specimens with mature capsules the spores remain indefinitely in herbaria, and can be recognized in sediments, etc. The spores of the first species, the type species of Anthoceros [Mich.] L., were described and illustrated (l.c.). This paper will deal with the second Linnean species, Anthoceros laevis the type species of the genus Phaeoceros Prosk. which together with P. carolinianus (Michx.) Prosk. are the most frequently encountered species of this genus. P. carolinianus is often considered to be a subspecies of the former (Proskauer 1954a, b, 1958), being disting­ uished from it only by its bisexual gametophyte. Proskauer has denied that spore characters have any value in distinguishing the subspecies (1958: 1316), a statement that would be correct if the two type specimens had the same kind of spore. It is the author's intention to show that these taxa are perfectly distinguishable by the ornamentation of their spores, and should not be regarded as subspecies of a single species.

HISTORICAL REVIEW When describing Anthoceros iaevis, Linne (1753, 2: 1139) cited five earlier ref­ erences, although he omitted Dillenius' first description (1719: 211) which was "Licl1en parvus, capitulis hypnoides clavatis" from "Gissa" (Giessen, German Federal Republic). Linne listed 1) "Lichen hepaticus, pediculis gramineis" Buxbaum (1728: 40, tab. LXI, fig. I n, b), from around ditches and springs in Bizant and the Orient, the illustra­ tion representing an anthocerote; 2) "Anthoceros major" Micheli (1729: 11, tab. 7,

1 Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Avda. Angel Gallardo 470, 1405 Buenos Aires, Argentina. 282 Journ. Hattori Bot. Lab. No. 62 1 9 8 7 fig. I), which presumably refers to the same species, found in the gardens of the town of Boboli, in field ditches and near the castle Villa Regia, the plate representing uni­ sexual thallii; 3) "Anthoceros" Linne (1738: 477); 4) "Anthoceros" Royen (1740: 507); and 5) "Anthoceros foliis mayoribus minus laciniatis" Dillenius (1742: 476, tab. LXVIII, fig. 2A & B). Thus in nomenclatural terms Anthoceros laevis L. is based on syntypes. As will be explained later, only the specimens corresponding to 2) and 5) are extant in herbaria. Linne's "Species Plantarum" (1753, 2: 1139) represents the starting point for the nomenclature of the Anthocerotopsida; in it he described A. laevis as "Anthoceros frondibus indivisis sinuatis laevibus", a diagnostic description of the thallus, besides indicating that the habitat of the species is Europe and America boreali. Proskauer (1951: 247) separated from the genus Anthoceros species with thalli lacking mucilage cavities, antheridia in which the wall cells are not organized in de­ finite rows, and yellow spores. For these he established a new genus Phaeoceros Prosk. and designated A. laevis L. as the type species. A few years later (1958: 1316) he chose as the lectotype, the plant referred to as "Anthoceros major" [Micheli 1729]. He stated (1958: 1315) that it was doubtful that Linne had a specimen of A. laevis in his herbarium in 1753, and that the plant of the "Hortus cliffortianus" could not be fo und (confirmed by Dr. A. Harrington 1986 pers. comm.). The plant on sheet no 1272 n. 2, in his herba­ rium could have been present, or sent by Schreber, but is very undesirable for selection as the lectotype since it lacks locality indication, Proskauer's lectotypyfication is not perfect, as indicated by Isoviita (1970 : 10, 16) and Grolle (1976: 217), who had doubts about the existence of Micheli's plant. From Proskauer's notes, "die von Linne zitierte Pflanze Micheli's uber die jeder Zweifel erhaben ist," it is not possible to tell whether he lectotipified on the basis of a specimen or Micheli's drawing. It was essential for the present author to confirm the existence of a type specimen, and to examine the spores of Micheli's original specimen, since drawings alone are quite insufficient for a present-day understanding of the Anthocerotopsida. Fortunate­ ly the pre-Linnean type specimen does exist in Micheli's herbarium in Firenze (Fl fig. I), as confirmed by the author in July 1985. Sheet "Anthoceros" 3355 (?3255) of Micheli's herbarium (a folder of yellowish paper with a pink reinforced back) contains a folded sheet to which is pinned a piece of paper, 7.5 x 10 cm. Stuck to this are two anthocerote plants, each with five sporo­ phytes. There is also an envelope containing four plants, each with two or three sporo­ phytes. All sporophytes are papyraceous and contain yellow spores. "Anthoceros punct." is written in pencil on the piece of paper to which the two plants are stuck whilst "Anthoceros punctatus" is written in another old hand on the back of the folded sheet ; there is no other labelling. These labels undoubtedly more recent, confuse the identity of the plants to which they refer. The specimens should be regarded as the "Iectotype" of Phaeoceros laevis (L.) Prosk. and should not have been labelled Anthoceros punctatus. Proskauer's choice (1958) was correct, since the only other extant specimen in Dillenius's herbarium comes from Virginia (U.S.A.). G. G. HASSEL DE MENENDEZ: Phaeoceros laevis and P. carolinianus spores 283

In his work "Historia muscorum ... " (1742) Dillenius described once again the plant from "Gissa" (corresponding to his fig. A) but added another plant from Virgi­ nia, sent to him by 1. Mitchell (indicated as 2B on the same plate). Dillenius mentions in his description that he did not notice "thecae" at the base, but that these were certain­ ly present on the specimen from Virginia. If "thecae" are the antheridial chambers, one can assume that this was a monoecious specimen. D illenius's herbarium at Oxford (U.K.) contains only the specimen from Virginia (see Hassei de Menendez 1984, lam. 1 right upper corner). A portion of this specimen is housed at H-SOL (lsoviita 1970: 16) (Fig. 3). Its spores are identical to those of "Anthoceros carolinianus", which Michaux (1803, 2: 280) described from a specimen from Carolina Inf., North America (fig. 2). It was S. O. Lindberg (1883: 37), in his revision of Dillenius' herbarium, who indicated that fig. B of Anthoceros JoWs majoribus" (1742, pI. LXVIII) represents A. laevis var. carolinianus (Michx.) Lindbg. and that figure A on the same plate, corresponds to A. laevis (specimen not extant), thereby originating the infraspecific status of "A. caro­ linianus" .

DESCRIPTIONS OF THE SPORES AND PSEUDOELA TERS 1) Phaeoceros laevis (L.) Prosk., Bull. Torrey Bot. Club 78: 347, 1951 = Anthoceros major Mich., Nova Genera 11, tab. 7 fig. I (1729), A. laevis L., Spec. Plant. 2: 1139, 1753 p.p. basionym; P. laevis subsp. laevis. (fig. 1). Spores yellow green, 33- 38 flm diam., distal surface with conic slightly curved spines, 1- 1,5 flm high, distributed irregularly up to the border, 11 - 13 spines across the diam., re­ maining surface smooth; equatorial rim (in transmitted light) 2- 3 mm wide; proximal surface with trilete mark (Iaesura) lower than the approximate verrucae of the margo, each verruca ca. 0.5-1 .urn high and wide; triangular areas covered with nearly round verrucae of ± 1 .urn diam., closer together than the distal spines, the intervening surface with low interwoven ornamentation. (With OM at x 600, distal spines visible, even around the border when seen in proximal view; triangular areas nearly flat, verrucae clearly distinguishable, trilete mark lower than margo verrucae). Pseudoelaters pale brown, transparent, simple or formed from 2- 3 adherent, cylindric, thin walled straight to curved cells, each 42-82 .urn long, 5-8.um in diam. Specimens examined: Anthoceros (Hb. Micheli, sheet 3355 or 3255?) (F1), holotype of Anthoceros major Mich ., lectotype of Anthoceros laevis L. fide Prorkauer 1958; Asciano ad radic. Mt. Pisani, Arcangeli 1897-1898 (fI).

2) Phaeoceros carolinianus (Michx.) Prosk., Bull. Torrey Bot. Club. 78 : 347, 1951 = Anthoceros loWs majoribus minus laciniatis Dill., Hist. musc. 476, pI. 68 fig. 2B, 1742; A. laevis L., Spec. Plant. 2: 1139, 1753 p.p.; A. carolinianus Michx., Flora bor.-amer. 2: 280, 1803, basionym; A. laevis var. carolinianus Lindb., Kritisk. Gr. Moss. Dill. Hist. Muse. Helsingsf. 371, 1883; P. laevis subsp. carolinianus (Michx.) Prosk., Rapp. et comm. VIII Congr. Int. Bot. Paris 14--16 : 69, 1954; P . laevis forma carolinianus Schust., Am. MidI. Natural. 49 : 296, 1953 (as fo. "carolinianus (Schweinitz)". (Fig. 2 and 3) Spores pale yellow, 42-47 (49) .urn diam.; distal surface with irregularly placed straight to curved, cylindric, simple or bifurcate at the apex attenuate spines, 2 .urn long in the centre, 0.5 .urn at the border, intervening surface smooth ; 17-21 spines across the diam.; equatorial 284 Journ. Hattori Bot. Lab. No. 62 1 987

FrG. 1. Phaeoceros laevis (L.) Prosk. 1) Detail of lectotype of Anthoceros laevis L. ( = ho)otype of Anthoceros major Micheli, 1729); 2) folder and sheets of the Micheli hepatic and anthocerote herbarium (Fl); 3-4) distal surfaces of spore; 5) detail of distal surface; 6) proximal surface; 7) detail of proximal face, margo and trilete mark to the left; 3-7 from Asciano ad radic Mt. Pisani, Arcangeli 1897- 98, identical to spores of the holotypes of A. major Mich. (Fr); scales equal 10 pm. G . G. HASSEL DE MENE DEZ: Phaeoceros /aevis and P. caro/inianus spores 285

.~-I#/I!,~H/ ,~tN/.~:/. fit:i ..4. ft.",,; 1 '

.( .... ~." .. ,'...... r.:.. :: ,'.'

FIG. 2. Phaeoceros carolinianus (Michx.) Prosk. 1) distal surface of spore; 2) detail of distal surface; 3-4) proximal surfaces; 5) detail of proximal face, trilete mark to the left; 6) details of isolectotype of Anthoceros carolinianus Michx. Carolina inferior (pc); 1- 5 from the holotype of A. carolinianus (pc); scales equal 10 /im. 286 Journ. Rattori Bot. Lab. No. 62 1 987

FIG. 3. Phaeoceros carolinianus (Michx.) Prosk. 1) equatorial view of spore; 2} distal surface; 3} detail ofdistal surface; 4} proximal surface; 5} detail of proximal surface; 6} en­ velope containing part of the syntype of Anthoceros laevis L. ( = isolectotype of Anthoceros Joliis majoribus minus laciniatis Dill. (H-SOL); 7-8) small envelope with label and capsules contained in upper envelope; \-6 from isolectotype of A. Joliis majoribus ... Dill. (H-SOL); scales equal 10 I'm. G. G. HXSSEL DE MENENDEZ: Phaeoceros laevis and P. carolinianus spores 287 rim (in transmitted light) 3- 5 I'm wide; proximal surface with well-defined, low, entire, narrow trilete mark, near the rim ending in obtuse border; triangular areas concave with fine inter­ woven noodle-like ornamentation, becoming small lines perpendicular to the border; elevated margo with the same texture, free of verrucae; in the centre of each area (0}-5-12 low verrucae, 0.1-0.6 I'm in diam., irregular in outline. (In OM at x 600, spines visible but difficult to in­ terpret, verrucae of the areas best seen in profile, trilete mark ending at obtuse border). Pseudoelaters pale brown, transparent, cells cylindric, curved of nearly twisted, 42-61 I'm long, 11 -1 2 I'm diam., isolated or 2- 3 adherent cells. Specimens examined: U.S.A, Carolina inferiori, herb. Camus, herb. Richard (pc), holotype of Anthoceros carolinianus Michx. In the author's opinion this specimen is the holotype if no other isotype exists but not a lectotype as indicated by Proskauer. "E. Virginia a Dr. Mitchell", herb. Dillenius, fol. 153 n02 (H-SOL) isolectotype of Anthoceros Joliis majoribus minus iaciniatis Dill. fide Lindbg. and Isoviita.

DISCUSSION In the Anthocerotopsida taxa can be distinguished at both the generic and the specific level by analyses of spore ornamentation and the multicellular elaters (Bhara­ dwaj 1971: 7). However the latter are only useful if a larger number are examined, since in some cases, they tend to break up and the fragments are frequently twisted or shrunken. The mature spores of one capsule, or of several capsules of the same plant, or of several specimens of the same species, have the same ornamentations with very little variation. If specimens belonging to one species have the same type of spore ornamentation, then subspecies, if they exist, should also have the same type of orna­ mentation, subspecific differences being restricted to the gametophyte, or to environ­ mental requirements, etc. Phaeoceros laevis and P. carolinianus have quite different spores that can be easily distinguished under the SEM and therefore should be regarded as distinct species and not merely SUbspecies. In Phaeoceros /aevis the spores and pseudoelaters are more deeply coloured, i.e. yellow-green and darker brown respectively than those of P. carolinianus. The spores are smaller, the proximal faces are densely covered with verrucae easily seen with OM, the trilete mark is lower than the verruca-covered margo, and the spines of the distal surface extend as far as the border, and are clearly seen over it in proximal view. In Phaeoceros carolinianus the spores are larger, the proximal triangular faces are concave with few central verrucae, the distal surface appears where the clearly defined trilete mark ends and the distal surrounding spines are scarcely visible in proximal view. As specimens of Phaeoceros with mature spores can be identified with the SEM, -OM is sufficient if SEM information exists - and the spores of the first two species of the genus described from Europa and North America are now known, it is expected that more bryologists will be encouraged to use this technique for the identification of specimens housed in European and North American herbaria, in order to establish which species are really present, their geographical distribution, ecological requirements, etc. It is hoped that future studies on other aspects of this genus will be based on spe- 288 Journ. Hattori Bot. Lab. No. 62 198 7

cimens, the distribution of which has been confirmed using the technique recommended in this paper.

ACKNOWLEDGEMENTS I am indebted to the curators Dr. P. Isoviita (Helsinki), Mr. H. Baudoin and Dr. H. Bischler (Paris) for the loan of specimens as well as to Dr. F. White (Oxford) for the photo­ graphs of specimens in the Dillenius herbarium. J am grateful to Prof. G. Moggi and his staff for the help I received at the Firenze herbarium. I wish to thank Mr. D. Gimenez and Mr. G. Garbarino for technical assistance with the SEM of the CEMIEBFO and finally Mr. J. Ban­ chero and Mr. M. Lamami who helped with the photographs. Travel expenses to Firenze were partially financed by the CONICET of Argentina, whose contribution is here acknowledged. My thanks also to Dr. A. Harrington for correcting the English of the manuscript.

R EFERENCES Bharadwaj, D. C. 1971. On Folioceros, a new genus of Anthocerotales. Geophytology 1(1) : 6-15. Buxbaum, J. C. 1728. Plantarum minus cognitarum centuria l. 46 pp., ind., 50 pI. Dillenius, J. J. 1719. Catalogus plantarum sponte circa Gissam nascentium, cum append ice. Franco· furti ad Moenum 240 pp. - - - .1742. Historia Muscorum. Oxford "1741" 1742, xvi + 576 p. Grolle, R. 1976. Verzeichois der Lebermoose Europas und benachbarter Gebiete. Feddes Reper­ torium 87(3-4): 171-279. Hassel de Menendez, G. G. 1984. Anthoceros punctatus L., sus esporas. Cryptogamie, Bryol. Lichenol. 5(1 -2): 201-209. Isoviita, P. 1970. Dillenius Historia Muscorum as the basis of hepatic nomenclature, and S. O. Lindenberg's collection of Dillenian bryophytes. Acta Botanica Fennica 89 : 1-28. Lindberg, S. D. 1883. Kritisk granskning af mossorna uti Dillenii Historia Muscorum. 59 pp. Hel- singfors. Linnaeus, C. 1753. Species plantarum, ed. 1, 1200 p. Holmiae. Michaux, A. 1803. Flora boreali-americana. Vol. 2, i-iii, 340. Paris-Strasbourg. Micheli, P. 1729. Nova Plantarum Genera Juxta Tournefortii Methodum Disposita. xxiv-xxvi + 234 p., \08 tab. Florentiae Proskauer, J. 1951. Studies on Anthocerotales Ill. Bull. Torrey Bot. Club. 78(4) : 331-349. - - . 1954a. A study of the Phaeoceros laevis complex. Rapports et Comunications VIII. Congres International de Botanique Paris xiv-xvi: 68. - - . 1954b. The European Anthocerotaceae. Rapports et Communications VIII. Congres International de Botanique, Paris xiv-xvi: 68-69. - - . 1958. Nachtrag zur Familie Anthocerotaceae, in Rabenhorst's Kryptogamenflora, ed. 3, 6: 1303-1319, fig. 508-514. Royen, A. van. 1740. Florae Leydensis Prodromus. 538 pp.