MALE GAMETES OF SPHAEROPLEA 185

consideration of the origin of other organisms with chloro- Wright, R. L., Chojnacki, B. & Jarvik, J. W. 1983. Abnormal phyll a and b. Bot. Reu. 41:104-35. basal body number, location and orientation in a striated Watson, M. W. 1975. Flagellar apparatus, eyespot and behavior fiber defective mutant of Chlamydomonas reinhardtii. J. Cell of Microthamnion kuetzingianum (Chlorophyceae) zoospores. Bid. 96: 1697-707. J. Phyco2. 11:439-48.

J. PhyCOl. 22, 185-193 (1986)

THE GENUS KUTZING (DELESSERIACEAE, RHODOPHYTA) IN THE TROPICAL WESTERN ATLANTIC, INCLUDING H. ANOMALUM SP. NOV.’

Michael J. Wynne2 Herbarium and Department of Biology, University of Michigan, Ann Arbor, Michigan 48109 and David L. Ballantine Department of Marine Sciences, University of Puerto Rico, Mayaguez, Puerto Rico 00708

ABSTRACT specimens from Charleston, South Carolina, on Observations are made on the occurrence and distri- which Harvey (1853) had based his record of Deles- bution of the red algal genus Hypoglossum Kutzing (Del- seria hypoglossum from North America, and Wiseman esseriaceae, ) in the tropical western Atlantic. confirmed that the plants were identifiable as the In addition to the type of the genus, H. hypoglossoides European species. Later Wiseman (1978) repeated (Stackh.) Coll. U Hem., three other species are reported: his contention that the South Carolina plants were H. anomalum sp. nov., H. involvens (Haru.)J. Ag., “closer” to H. hypoglossoides yet retained the name and H. tenuifolium (Ham.)J. Ag. A key is presented to H. tenuqolium in his report. Recently Yarish et al. distinguish thesefour species. The newly described species, (1984) characterized H. hypoglossoides (as H. woodwardii) H. anomalum, is like other species in the genus in that as belonging to the “warm temperate Mediterra- its branches arise endogenously from the primary axial nean Atlantic” group of species, with a distribution row but it is unique in that the branches emerge from the restricted to the Mediterranean and eastern North parent blade at some point between the midline and the Atlantic. margin of the blade. The new species is reported from Two other taxa have been described, both from Puerto Rico and Florida. Curacao by Sluiter (1908). Hypoglossum tenuqolium f. schoonhoveni was distinguished by Sluiter by its large Key index words: Delesseriaceae; H ypoglossum; Hy- median tetrasporangial sorus; Taylor (1960) did not poglossum anomalum sp. nov.; Rhodophyta; tropical maintain it as a separate form. Zellera boekei Sluiter western Atlantic appears to be a Hypoglossum and was regarded by Taylor (1960) as a possible synonym of H. involvens. In contemporary literature two species of Hypo- On the basis of Sluiter’s illustrations it seems more glossum Kutzing are recognized to be present in the likely to be H. tenuqolium. tropical and sub-tropical western Atlantic: H. invol- A fundamental characteristic of Hypoglossum and vens (Harv.) J. Ag. and H. tenuqolium (Harv.) J. Ag. the other genera in the Hypoglossum Group is that (Taylor 1960, Chapman 1963, Croley and Dawes the initials of all 3rd-order rows reach the margin 1970, Earle 1972, Almodhvar and Ballantine 1983). of the blade (Nageli 1845, Wynne 1983). In their For the latter species the variety carolinianum Wil- study of southern Australian species of Hypoglossum liams is usually recognized (Searles and Schneider Womersley and Shepley (1982) observed that in some 1978, Kapraun 1980). In older literature, however, species of the genus, including the type, each cell of the European-based type of the genus, H. hypoglos- the 2nd-order rows bears a 3rd-order row but that soides (Stackh.) Coll. & Herv., had been reported to in other species not all cells of the 2nd-order rows occur in the western Atlantic [Harvey 1853 (as Deles- bear 3rd-order rows. This same difference can be seria hypoglossum), Murray 1888, Collins and Hervey observed among collections of Hypoglossum from 19 171. Wiseman (1966) re-examined the original Puerto Rico. Based upon our study of recent col-

~ lections, we have been able to discriminate four Accepted: 28 January 1986. species of Hypoglossum in the tropical western Atlan- Address for reprint requests. tic, including an undescribed species. MICHAEL J. WYNNE AND DAVID L. BALLANTINE

FIGS. 1-7. Hypoglossum anomalum sp. nov. FIG. 1. Apex of blade. FIG. 2. Apical region, with initials of 2nd- and 3rd-order rows reaching blade margin. FIGS.3 & 4. Opposite arrangement of blade primordia. FIG. 5. Location of emergence of blade between midline and blade margin. FIG. 6. Young blade emerging from parent blade. FIG. 7. Unequal development of a pair of blades. Scale bars: 40 pm (Figs. 1, 2); 75 pm (Figs. 4, 6); 150 pm (Figs. 3, 5, 7). WESTERN ATLANTIC HYPOGLOSSUM 187

FIGS.8-1 1. Hypoglossum anomalum sp. nov. FIG.8. Endogenous origin of blade from axial row but its emergence from parent blade at a point between midline and margin of parent blade. FIG.9. Habit of alga. FIG. 10. Development of rhizoids from both margin and midregion of blade. FIG. 1 1. Cross-section of blade, with multicellular rhizoid.

MATERIALS AND METHODS and of the University of Michigan (MICH). Herbarium abbre- viation' are according to Holmgren et SCUBA-collected or drift specimens were preserved in 5% for- (1981)' malin-seawater, and whole-mount slides were later prepared. Por- tions of thalli were placed on glass slides and stained with a mix- RESULTS AND DISCUSSION ture of 1% aniline blue/l M HCI/Karo syrup/water (4:1:20:75). It is possible to distinguish four species ofHypoglos- A standard Zeiss research microscope, equipped with a camera sum occurring in the tropical western Atlantic: H. back and a drawing tube, was used for preparing the artwork. Voucher specimens have been deposited in the herbaria of the anomaLum'P. nov*,H. hYPoglossoides(Stackha) cO1l. & Department of Marine Sciences, University of Puerto Rico(MSM) HerV.9 H. induens (Harv.)J. Ag., and H. tenuqofolium 188 MICHAEL J. WYNNE AND DAVID L. BALLANTINE

FIGS.12-1 7. FIGS.12- 15. Hypoglossurn anomalum sp. nov. FIGS.16 and 17. Hypoglossurn hypoglossoides. FIG.12. Tetrasporangial sorus. FIG. 13. Tetrasporangia. FIG. 14. Well developed pair of branches and rhizoid from midline. FIG. 15. Fusion of adjacent blades. FIG. 16. Apex of blade. FIG. 17. Endogenous origin of branch, with its immediate emergence. Scale bars: 40 wm (Figs. 13, 16, 17); 150 pm (Figs. 12, 14, 15). WESTERN ATLANTIC HYPOGLOSSUM 189

(Harv.)J. Ag. The following key is used to delineate Holotype: D. L. Ballantine 1782, 16.i. 1985, 6 1 m these taxa: depth, edge of insular shelf, offshore from La Par- 1. Branches occurring singly or in opposite pairs, arising guera, Puerto Rico. Deposited in MICH. and emerging from the midline of midrib of the parent Isotypes deposited in DUKE, MSM, NCU, and blade ...... 2 us. 1. Branches occurring in opposite pairs, emerging at points Additional collections: PUERTO RICO. Edge of between the margin and midline (midrib) of the parent insular shelf, offshore from La Parguera: Ballantine blade ...... Hypoglossum anornalum 2. Apices of blades strongly incurved; localized patches 1719, 16.i.1985 (58 m, on coral rubble); Ballantine of cells forming bullations that appear as a broad, 1789 tetrasporic, 14.i. 1985 (50 m); Ballantine 1823, conspicuous row or border just within the margins of 1 1.i. 1985 (40 m); Ballantine s. n., 4.xii. 1985 (30 m). the blade ...... H. involvens Edge of insular shelf, offshore from Salinas: Ballan- 2. Apices of blades not strongly incurved; bullations along tine 891d, 5.i.1982 (30 m, on worm casings); Ballan- the blade margins not present ...... 3 tine 1174b, tetrasporic, 17.i.1983 (27 m, on coral 3. A 3rd-order row produced from every cell of the 2nd- rubble). FLORIDA. Dry Tortugas, dredged off order rows; blades typically elongate, attenuate; sori broad, tetrasporangia arranged irregularly in the sorus ...... southwest channel (station 2 15): Taylor 1024 ...... Hypoglossurn hypoglossoides 1 l.iv.1925 (36 m; MICH). 3. A 3rd-order row not produced from every cell of the The most distinctive feature of Hypoglossum anom- Pnd-order rows; blades typically broadly spathulate, blunt- alum, and the reason for the specific epithet, is its tipped; tetrasporangia arranged regularly in narrow lin- unique manner of branching. The initial of a branch ear sori along the midline ...... Hypoglossurn tenuijolium is cut off endogenously from a primary axial cell, as is typical for the genus (Fritsch 1945). However, instead of immediately emerging from the parent Hypoglossum anomalum sp. nov. blade at that point, the initial undergoes divisions. (Figs. 1-15) This results in a filament that grows in the plane of Alga e laminis repentibus, undulatis, usque ad 30 mm the parent blade along a course parallel to that of a longis, et 1.0-1.8 mm latis constituta, monostromatica 2nd-order row of cells (Figs. 5, 8). Invariably two praeter costam, e stipitibus brevibus cylindricis cortca- such branch primordia are cut off from the same tisque enascentibus; laminae ad substratum secundarie axial cell, producing a pair of opposite bladelets (Figs. afixae per rhizoidea uniseriata ramosaque e latere abax- 3,4, 9). At some point between the midline and the iali regionis costae, aut e cellulis pericentralibus aut e margin of the parent blade, each of the branch pri- derivitiuis cellularum pericentralium regionis costae en- mordia emerges from the plane of the parent blade, ascentia; rhizoidea e margine laminae quoque aliquando typically on the same surface. The young blades are procreata; omnis cellula secundi ordinis series cellularum then evident as branches and proceed to broaden tertii ordinis ferens; ramijicatio laminarum ad duos or- into blades similar to the parent blade (Fig. 6). The dines, opposita saepe inaeque evoluta; primordia ramo- axial row which connects blades to the parent axis rum e cellulis axialibus primariis endogene initiata, la- becomes corticated with age. Sometimes a branch mella, autem, e lamina parentis non emergente prius pope emerges close to the midrib, more typical of Hypog- locum inter costam atque marginem laminae parentis; lossum, but at other times a branch emerges closer tetrasporangia in soris ovatis per regionem costae sym- to the blade margin, superficially resembling the metrice procreata; sororum longitudo indefinita et latitudo branching in Branchioglossum. 500 pm; tetrasporangia usque ad 70 pm diametro. Although the branch primordia of each pair have Alga consisting of repent, undulate blades, to 30 a comparable sequence of growth to the time of their mm long and 1.O-1.8 mm wide, monostromatic ex- emergence from the parent blade, there often is a cept along the midrib, arising from short, cylindri- subsequent unequal development, one of the mem- cal, corticated stipes; blades secondarily attached to bers of the pair growing more rapidly than the other substrate by uniseriate, branched rhizoids arising (Fig. 7). There are about 25 species of Hypoglossum from abaxial side of the midrib region (Figs. 11 and now recognized (Wynne and Kraft 1985), and we 14), either from pericentral cells or their derivatives know of no other species of Hypoglossum that has in the midrib region; rhizoids also occasionally pro- been described as having this unusual pattern of duced from the blade margin (Fig. 10); all 2nd-order branch initiation. We have also observed the lateral cells bearing 3rd-order cell rows (Figs. 1 and 2); fusion of adjacent blades (Fig. 15). branching of blades to two orders, opposite, often Hjpoglossum hypoglossoides (Stackhouse) of unequal development; branch primordia initiated Collins 8c Hervey endogenously from primary axial cells but bladelet (Figs. 16, 17) not emerging from parent blade until some point between midrib and margin of parent blade; tetra- Syn.: hypoglossum (Woodw.) Lamour. sporangia produced in ovate sori symmetrically along Hypoglossum woodwardii Kutz. (see Wynne 1984). midrib region; length of sori indefinite and width H. tenufolium var. carolinianum Williams 500 pm (Fig. 12); tetrasporangia to 70 pm in di- Recent collections. PUERTO RICO. Edge of in- ameter (Fig. 13). sular shelf, offshore from La Parguera, growing on 190 MICHAEL J. WYNNE AND DAVID L. BALLANTINE, WESTERN ATLANTIC HYPOGLOSSUM 191

Verongia: Ballantine 15, 18.xii.1978 (18 m); 1.6 km blades. The blade is not flat in this region, but groups seaward of Margarita Reef, La Parguera: Ballantine of cells have collectively formed broad pockets, or 2102, 30.vi.1985, female (24 m, epiphytic on Udo- concavities, and these bullations occur in two long tea). 1.5 km seaward of Media Luna Reef, La Par- series creating the borders noted in Harvey’s orig- guera: Ballantine 1843, 24.i.1985 (17 m). BELIZE. inal description. Long Cay, growing on Verongia: Ballantine 379, The blades of Hypoglossum involvens are extremely 27.vi.1979 (29 m). delicate and filmy, much as in H. tenufolium, and Hypoglossum hypoglossoides has been confused with they are much branched and fastigiate also as in that H. tenufolium in the past. They differ in that in H. species. The blades tend to be very narrow, usually hypoglossoides all cells of the 2nd-order rows bear 3rd- less than 1 mm wide, and the apices of the blades order cell rows, as has been depicted in this species are attenuated rather than blunt as in H. tenuqolium. by Kylin (1923 and 1924, as H. woodwardii). This Tetrasporangia are confined to a narrow sorus run- pattern is demonstrated in Figure 16. Other features ning indefinitely along the midline of the blades (Fig. serve to separate these two species. Vegetatively, the 18). Mature tetrasporangia measure 50-70 pm diam. midline in young blades of H. hypoglossoides is un- This species appears to be rather rare, and ac- corticated, but it becomes corticated with numerous cording to A. Hine’s notes on the specimen in USM, closely spaced cells in older blades. The midline of it is an “ephemeral spring plant, occurring only in blades in H. tenuqolium tends to remain uncorticated, April and May, sometimes into June.” The specimen although basal portions of thalli do become corti- from Knight Key (Wynne 4424), however, was col- cated. Reproductively, tetrasporangial sori in H. hy lected in late December; it does not have the bul- poglossoides form broad continuous or interrupted lations but otherwise agrees with H. involvens. arrangements on either side of the midrib (Kylin The record of occurrence of this species in Puerto 1924), whereas those in H. tenuqolium form scattered Rico by Almodbvar and Ballantine (1 983) was based patches from individual cells on the blade. Branches on the single collection by V. Rosado (Almodhar arise endogenously from primary axial cells and 5958, in MSM & MICH), but it conforms to H. hy- emerge from the midline (Fig. 17), which is similar poglossoides rather than H. inuoluens. For the present, to the mode of branching in H. tenuifolium and H. then, H. inuolvens is removed from the flora of Puer- involvens but dissimilar to that of H. anomalum. to Rico and is known only from Florida. Hypoglossum involvens (Harvey) J. Agardh Hjpoglossum tenufolium (Harv.) J. Ag. (Figs. 18-20) (Fig. 21-25) Recent collections: FLORIDA. Florida Keys, Key Recent collections: PUERTO RICO. 1.5 km sea- Largo: Hommersand (in NCU, MICH), 4.iv. 1965. ward of Media Luna Reef Ballantine s. n., Upper Matacumbe Key: Hine 668-134 (in USF 29.viii.1973 (17 m); Ballantine s. n., 19.ii.1974 (17 1528l), cystocarpic & tetrasporic, 12.vi. 1968, epi- m); Ballantine 1676, tetrasporic, 7.xii. 1984 (17 m). phytic on Thalassia. Knight Key: Kapraun & Wynne Edge of insular shelf, off Margarita Reef Ballantine 4424 (in MICH), tetrasporic, 3 1.xii. 1975. 67, female & tetrasporic, 6.iv.1978 (30 m); Ballantine Hypoglossum involvens was described by Harvey 1518, male, 12.ii.1984 (27 m, on Verongia). 1.6 km (1853) from Key West, Florida. Harvey referred to seaward of Margarita Reef: Ballantine 1652, female, two morphological features that clearly distinguish 10.xi.1984 (27 m); Ballantine 2020, 7.iii.1985 (27 it from the other species of the genus in the western m); Ballantine 2101, male, 30.vii.1985 (27 m; epi- Atlantic, namely, the strongly involute blade apices phytic on Udotea). (Fig. 18)and a conspicuous border of bullations along This species was described by Harvey (1853) as the blade margins (Figs. 19, 20). The former char- Delesseria tenuqolia from Key West, Florida, and was acteristic is more easily observed in fresh or wet- later transferred to Hypoglossurn by J. Agardh (1898). preserved specimens than in pressed material. The Harvey stated that the blades were exceedingly thin latter characteristic persists even in wet-preserved (hence, the specific epithet) and semi-transparent or herbarium specimens that have been soaked up. and that the blades were more delicate than those Harvey’s (1 853) plate XXIJ-A, figure 3, aptly depicts in the type of the genus. Harvey described the tet- the distinctive appearance of the interrupted zone rasporangial sori as being very small and placed on of elongate cells running inside the margins of the either side of the midrib, very close to the tips of

t

FIGS.18-25. FIGS.18-20. Hypoglossurn inuoluens. FIGS.2 1-25. Hypoglossum tenuijolzum. FIG.18. Blade with incurved apex and bearing tetrasporangia with bullations evident. FIG. 19. Portion of a blade with row of marginal bullations. FIG. 20. Cystocarpic blade. FIG. 21. Female blade bearing procarps. FIG. 22. Tetrasporangial sorus. FIG.23. Cystocarp on midline of blade. FIG.24. Blade bearing young spermatangial sori. FIG. 25. Older male blade, with spermatangial sori coalescing into bands. Scale bars: 40 prn (Figs. 21, 24); 75 pm (Figs. 20, 22); 200 pm (Figs. 23, 25). 192 MICHAEL J. WYNNE AND DAVID L. BALLANTINE young blades. He also distinguished this species from to maintain it as a distinct variety but would merge H. hypoglossoides by the midrib having an articulate it within H. hypoglossoides. appearance and consisting of a triple row of cells, with large polygonal cells lying along the midline. We wish to acknowledge the financial support to D.L.B. from In the basal parts of the thalli the axes are denuded, the Office of Research Coordination, University of Puerto Rico, and the midrib does become thickened, to about 2 Recinto Mayaguez. We thank Dr. Bruce Hansen for the loan or 3 mm in diameter. from the USF Herbarium, Tampa, Florida. We are also grateful to Ms. Gladys Collazo for some of the artwork, Ms. Carolyn Various authors (Bargesen 1919, Taylor 1942, Holland for typing the manuscript, and Dr. Hannah Croasdale 1960) have described this alga as forming bushy, and Mrs. Angela Shipman for providing the Latin diagnosis. much branched, fastigiate clumps, the blades closely overlapping, like pages in a book. The color has Agardh, J. G. 1898. Species genera et ordines algarum been said to be “light pink to greenish, or nearly (3). Gleerup, Lund, 239 pp. colorless” (Taylor 1960). Almod&ar, L. R. & Ballantine, D. L. 1983. Checklist of benthic Another feature which separates Hypoglossurn ten- marine macroalgae plus additional species records from uijolium from the three other species of the genus Puerto Rico. Carib. J. Sci. 19:7-19. occurring in the tropical western Atlantic is that not Bsrgesen, F. 191 0. Some new or little known West Indian Florid- eae. 11. Bot. Tidsskr. 30:177-207. all cells of the 2nd-order rows produce 3rd-order 1919. The marine algae of the Danish West Indies. Part rows (Figs. 2 1 and 24). (See also Bargesen 1919, fig. 111. Rhodophyceae. 5. Dansk Bot. Ark. 3:305-68. 341b.) Thus, one does not see the crowding effect Chapman, V. J. 1963. The marine algae ofJamaica. Pt. 2. Phaeo- of secondary and tertiary initials along the margins phyceae and Rhodophyceae. Bull. Inst. Jamaica, Sci. Ser. No. 12 (2),201 pp. near blades’ apices that is characteristic of those Collins, F. S. & Hervey, A. B. 1917. The algae of Bermuda. Proc. species in which 3rd-order rows are produced from Am. Acad. Arts Sci. 53:l-195. every cell of the 2nd-order rows. The apices of blades Cordeiro-Marino, M. & Guimaraes, S. M. P. B. 1981. Novas are usually blunt (Fig. 24) but may be attenuate if referencias para a flora marinho de profundidade do Brad. Rickza 9:61-70. rapidly growing (Fig. 21). A further useful trait in Croley, F. C. & Dawes, C. J. 1970. Ecology of the algae of a recognizing H. tenuijolium is the orderly appearance Florida key. I. A preliminary checklist, zonation, and sea- of the tetrasporangia in the narrow sori at least in sonality. Bull. Mar. Sci. 20:165-85. the early stages. The tetrasporangia are less orderly Earle, S. A. 1972. The influence of herbivores on the marine arranged in older sori. Tetrasporangia are arranged plants of Great Lameshur Bay, with an annotated list of plants. In Collette, B. B. & Earle, S. A. [Eds.] Results of the symmetrically along and directly over the midline Tektite Program: Ecology of Coral Reef Fishes. Natural History (Fig. 22), as also shown by Bargesen (19 19, fig. 34 1b). Museum, Los Angeles County, Sci. Bull. 14, pp. 17-44. The spermatangial sori in H. tenuijoliurn are pro- Fritsch, F. E. 1945. The Structure and Reproduction of the Algae. duced initially from scattered individual cells (Fig. Vol. II. Foreward, Phaeophyceae, Rhodophyceae, Myxophyceae. University Press, Cambridge, xiv + 939 pp., 2 fold-out maps. 24). In older blades, spermatangial sori typically co- Harvey, W. H. 1853. Nereis Boreali-Americana. 11. Rhodosper- alesce into larger bands running diagonally out from mae. Smithson. Contrib. Knowledge 5(5):1-258. the midline (Fig. 25). The urn-shaped cystocarps Holmgren, P. K., Keuken, W. & Schofield, E. K. 1981. Index occur on the midline (Fig. 23), and their appearance Herbariorum. Part I. The Herbaria of the World. Ed. 7. Bohn, conforms to Bargesen’s (19 10, 1919) accounts. Scheltema & Holkema; Utrecht. (Regnum Vegetabile vol. 106). Kapraun, D. F. 1980. An Illustrated Guide to the Benthic Marine From the various illustrations provided in their Algae of Coastal North Carolina. I. Rhodophyta. University of papers, it is evident that H. tenufolium is present in North Carolina Press, Chapel Hill, vii + 206 pp. the Virgin Islands (Bargesen 1919), North Carolina Kusel, H. 1972. Contribution to the knowledge of the seaweeds (Schneider 1975), Cuba (Kusel 1972), Colombia of Cuba. Bot. Mar. 15: 186-98. (Schnetter and Bula Meyer 1977), and Brazil (Cor- Kylin, H. 1923. Studien uber die Entwicklungsgeschichte der Florideen. K. Svensk Vetenskapsakad. Handl. 63:l-139. deiro-Marino and Guimaraes 1981). However, the 1924. Studien uber die Delesseriaceen. Lunds Univ. Arsskr. single figure given by de Rios (1972) for her record (N.F. Avd. 2) 20(6):1-111. of H. tenuqoliurn in Venezuela would appear to rep- Murray, G. 1888. Catalogue of the marine algae of the West resent H. hypoglossoides. Indian region. J. Bot., Brzt. Forezgn 26:237-43. Nageli, C. 1845. Wachstumsgeschichte von Delesseria Hypoglos- Williams (1 949, 1951) likened his newly described sum. Zeitsch. Wiss. Bot., Zurich 1:121-37, 1 pl. Hypoglossum tenuijoliurn var. carolinianurn to the Eu- Oliveira, E. C. de. 1969. Algas marinhas do sul do Estado do ropean type of the genus (i.e. H. hypoglossoides). The Spirito Santo (Brad). 1. Ceramiales. Bol. Fil. Cihc. Letr. Sio variety was described from shallow water and stated Paulo No. 343 (Bot. 26). 277 pp., map, index, & errata. Rios, N. R. de. 1972. Contribucion a1 estudio sistematico de las to have a height of only 1 cm. It is clear from both algas macroscopicas de las costas de Venezuela. Acta Bot. Ve- Williams’ (1949) figures and those of Kapraun (1980) npz. 7~219-324,42 pls. for this variety that this taxon, var. carolinianum, is Schneider, C. W. 1975. North Carolina marine algae. V. Ad- in agreement with H. hypoglossoides in regard to or- ditions to the flora of Onslow Bay, including the reassign- ganization of the apex, appearance of the tetraspo- ment of Fauchea peltata Taylor to Weberella Schmitz. Br. Phy- CO~.J. 10:129-38. rangial sori, and other features. Likewise, Oliveira’s Schnetter, R. & Bula Meyer, G. 1977. Rodoficeas nuevas para (1969) record and figures for this variety from Brazil la costa Atlantica de Colombia. An. Inst. Inv. Mar.-Punta Betin also appear to be this same entity. We see no reason (Santa Marta, Colombia) 9:81-90. WESTERN ATLANTIC HYPOGLOSSUM 193

Searles, R. B. & Schneider, C. W. 1978. A checklist and bibli- Annotated Checklist of the Biota of the Coastal Zone of South Car- ography of North Carolina seaweeds. Bot. Mar. 2 1:99-108. olina. University of South Carolina Press, Columbia, pp. 23- Sluiter, C. P. 1908. List of algae collected by the Fishery In- 36. spection at Curasao. Recud Trav. Bat. Nierl. 4:231-41, pl. 8. Womersley, H. B. S. & Shepley, E. A. 1982. Southern Australian Taylor, W. R. 1942. Caribbean marine algae of the Allan Han- species of Hypoglossum (Delesseriaceae, Rhodophyta). Austral. cock Expedition, 1939. Allan Hancock Atlantic Exped. Rep. No. J. Bot. 30:321-46. 2. Univ. of Southern Calif. Press, Los Angeles, 193 pp. Wynne, M. J. 1983. The current status of genera in the Deles- - 1960. Marzne Algae of the Eastern Tropical and Subtropical seriaceae (Rhodophyta). Bot. Mar. 26:437-50. Coasts of the Americas. University of Michigan Press, Ann Ar- - 1984. The correct name for the type of Hypoglossum bor, Ix + 870 pp. Kutzing (Delesseriaceae, Rhodophyta). Taxon 33:56-8. Williams, L. G. 1949. Seasonal alternation of marine floras at Wynne, M. J. & Kraft, G. T. 1985. Hypoglossum caloglossoides sp. Cape Lookout, North Carolina. Am. J. Bot. 35:682-95. nov. (Delesseriaceae, Rhodophyta) from Lord Howe Island, -1951. Algae of the Black Rocks. In Pearse, A. S. & Wil- South Pacific. Br. Phycol. J. 20:9-19. liams, L. G. [Eds.] The Biota ofthe Ree& offthe Carolinas, pp. Yarish, C., Breeman, A. M. & van den Hoek, C. 1984. Tem- 149-159. J. Elisha Mitchell Sci. SOC.67:133-61. perature, light, and photoperiod responses of some northeast Wiseman, D. R. 1966. A preliminary survey of the Rhodophyta American and west European endemic rhodophytes in re- of South Carolina. Masters thesis, Duke University, Durham, lation to their geographic distribution. Helgol. Meeresunters. North Carolina. 38:273-304. -- -- 1978. Benthic marine algae. In Zingmark, R. G. [Ed.] An

J. Phycol. 22, 193-198 (1986)

INCORPORATION OF TRITIATED THYMIDINE BY EUCARYOTIC MICROALGAE'

Richard B. Rivkin Horn Point Laboratories, University of Maryland, Cambridge, Maryland 2 16 13

ABSTRACT However, the incorporation of the radiolabelled nu- The uptake and incorporation of tritiated thymidine cleoside [3H] thymidine (thymine deoxyribose: TdR) (3H-TdR)by axenic laboratory cultures of marine diatoms into DNA has a long history of use in cell biology and dinoflagellates was measured. 3H-TdR was incor- (Gelfant 1966, Cleaver 1967, Van't Hoff 1968, Met- porated into nucleic acids by all four algae examined zler 1977, Dirksen et al. 1978). The ability of higher during a two to six hour period prior to cytokinesis and plants, animals and bacteria to take up and incor- not during other times of the cell cycle. Between 90-95% porate 3H-TdRinto nuclear DNA has been well doc- of the 3H label incorporated into (cold trichloroacetic acid umented (Firket and Verly 1958, Cleaver 1967, Da- insoluble) nucleic acids was recovered from DNA. Incor- vidson 1968). However, TdR uptake and metabolism poration of 3H-TdR appears to accurately indicate the has not been extensively studied in microalgae (Sa- timing of DNA synthesis. The incorporation of 3H-TdR by gen 1965, Galleron and Durrand 1979, Lloyd and eucaryotic algae during long term (24 h) incubations does Cantor 1979). not generally preclude using 3H-TdR uptake to estimate For most eucaryotic algae the cell division cycle bacterial production and growth during short term in- is composed of four discrete, sequential intervals cubations. (Chisholm 1981, Puiseux-Dao 1981). Typically two temporal gaps (G-1 and G-2 stages) separate periods Key index words: algae; cell division; DNA; diatoms; of DNA synthesis (S-stage) from cell division (D- dinoflagellate; nucleic acids; RNA; thymidine; tritium stage, karyokinesis and cytokinesis). New DNA is formed by semi-conservative replication. Thus when Nucleic acids from all microorganisms are assem- 3H-TdR is supplied exogenously, it could be taken bled from the same five nucleotide bases; however, up and phosphorylated to thymidine monophos- only three of the five component nucleotides are phate (dTMP) by the salvage pathway enzyme thy- common to both RNA and DNA. All nucleic acid midine kinase. Further phosphorylation by thymi- contains adenine, guanine and cytosine with thy- dylate kinase to deoxythymidine 5-triphosphate mine being unique to DNA, and uracil being unique (dTTP) precedes incorporation into DNA. 3H-thy- to RNA. The specificity of the thymine to DNA midine would thus be incorporated into replicating makes it an ideal tracer of DNA metabolism. Ra- DNA only during the S-interval of the cell cycle diolabelled thymine is not readily incorporated into (Davidson 1968, Natchtwey and Cameron 1968). DNA (Crawford 1958, Cleaver 1967, Munch-Peter- Several recent laboratory studies have reported in- sen 1970) and has not been extensively studied. significant incorporation of 3H-TdR by marine cy- anobacteria and eucaryotic algae (Cuhel and Wa- ' Accepted: 30 January 1986. terbury 1984, Pollard and Moriarty 1984, Bern