NORTH CAROLINA MARINE ALGAE. HI. A COMMUNITY OF (RHODOPHYTA) ON A GLASS SPONGE FROM 60 METERS

CRAIG W. SCHNEIDER Department ot Botany, Duke University, Durham, N.C. 27706

ABSTRACT Five members of the Ceramiales (Rhodophyta) are recorded from 60 m at the shelf break off North Carolina. These include two taxa pre- viously reported from shallow waters in N.C., A ntithamnion cruciatum (C. Agardh) Naegeli v. radicans (1. Agardh) Collins and Hervey and Callithal/1nioll byssoides Arnott in Hooker, one plant not previously re- ported from this area, Heterosiphonia wurdemanni (Bailey ex Harvey) Falkenberg v. Jaxa B¢rgesen, and two new species, Branchioglossum prostratum sp. nov. and subtropica sp. nov. This is the first report of the genus Branchioglossum from the Atlantic Ocean.

INTRODUCTION This report is part of the continuing study of the benthic offshore flora on the continental shelf of Onslow Bay, North Carolina (Searles, ] 972; Schneider and Searles, 1973). Onslow Bay is located between Cape Look- out and Cape Fear and extends to the inner edge of the Gulf Stream. The benthic algal flora of this area is characteristically tropical. The present re- port describes one particular deep water community of in the order Ceramiales growing epizoically on a glass sponge. The five taxa reported are of interest floristically and because of the depth at which they were col- lected, 60 m. Two of these species have been collected in North Carolina from shallow water and one is new to this area. The remaining two entities are not previously reported in the literature and are added to those recently described from Onslow Bay (Searles, 1972).

THE COLLECTION SITE The algae described .in this report were collected on June 30, ] 970 during cruise E-11-72 of the RjV EASTWARD. The glass sponge on which they were growing was collected from the second of two fifteen-minute rock dredges (Station No. 20459, 33°28.5'N, 76°58.3'W) made at a depth of 60 III along the shelf break at the outer edge of the continental shelf in Onslow Bay. This part of the shelf lies next to the Gulf Stream system and a bathy- thermograph cast at the dredge site indicated a bottom temperature of 20.3°C. The five taxa taken from the glass sponge were the only algae collected in either dredge. 1094 Bulletin of Marine Science [24(4) Ceramiaceae Antithamnion cruciatum (C. Agardh) Naegeli v. radicans (1. Agardh) Collins and Hervey This variety has previously been collected from North Carolina on a buoy near Cape Lookout by Blomquist and Humm (1946). It is known only from shallow water (Collins and Hervey, 1917), therefore our collec- tion constitutes a new depth record for this taxon. These deep water plants lack gland cells. Collections of plants from other areas in Onslow Bay indicate the presence of gland cells is not consistent. In a review of the literature on this genus, Wiseman (1966) indicates that the gland cells have been found to be of little taxonomic significance. L'Hardy-Halos (1968), however, separated species on the basis of pres- ence or absence of 'cellules secretices' in determining species from the coast of Brittany. Until a more definitive study can be made on all North Carolina plants, I am retaining these deep water specimens in A. cruciatum v. radicans.

Callithamnion byssoides Arnott in Hooker The plants from 60 m are strikingly similar in most respects to those I have collected from the intertidal near Beaufort and those reported by Williams (1948) from Cape Lookout. The major difference of these plants from markedly dissimilar habitats seems to be that those from deep water are only to 1 cm in height while those from the jetties are usually larger, often to 4 or 5 cm. The deep water plants also have occasional uniseriate rhizoids arising randomly from the main filaments. It is possible that C. byssoides in this case is prostrate in habit, just as are three of the other species reported here. These differences are not, however, significant enough to warrant the erection of a new species or variety.

DeIesseriaceae Branchioglossum prostratum sp. nov. (Figs. lA,2) Thallus prostratus, expansus, exoriens interdum a brevi stipete interdulll anastomosans, per affixi rhizoideum hapteron et numerosis secundaris, mul- ticellulosis, uniseriatis rhizoideis exorientibus margine; rami aIterni (raro oppositi) ad secundum 2-3 ordinum, omnes marginales, apices acuti; prin- cipalis thallus 0.8-1.5 mm latum, rami ad 0.7 mm; costa inconspicua, axi- ales cellulae ad 40 /.Lmlatas, 185 /.LmaItas, cum serie brevium lateralium cellularum in alteruteo latere, et series brevium transversaliuID cellularum supra et sub costam quum visa planam paginam, corticata non nisi ad basim; tetrahedral is sporangia 30-40 /.LIDin elongatis oppositis soris; sori con- 1974] Schneider: Marine Algae from North Carolina 1095

FIGURE 1. A, Branchioglossum prostratum sp. nov., with tetrasporangial sori; B, Memhranoptera subtropica sp. nov., with tetrasporangial sori; scales 1 em. tingentes cum costam efferentes dilatatas thalli; monoecius, spermatangia in irregulariter dispositis e10ngatis c1ustris medianis inter costam et mar- ginem, thalli feminei cum procarpia factas seriatas ab apice secus costam, cystocarpia ignota. Plant prostrate, spreading, arising sometimes from a short stalk attached by a rhizoidal holdfast and numerous secondary attachments by multicellu- lar, uniseriate rhizoids which arise randomly from the margin; branches alternate (rarely opposite) to secund of 2-3 orders, all marginal, the apices acute; main part of the plant 0.8-1.5 mm wide, the branches to 0.7 mm; midrib inconspicuous, axial cells to 40 /lm wide, 185 /lm long, with a row of shorter lateral cells on each side, and a row of shorter transverse cells above and below when viewing the flat surface, corticated only at the base; tetrahedral sporangia 30-40 J.im in elongated opposite sori; sori contiguous with the midrib causing a broadening of the plant; monoecious, spermatan- gia in irregularly spaced elongate clusters midway between the midrib and the margin, female plants with procarps formed seriately from the apex along the midrib, cystocarps unknown. The morphological characters of this alga are distinct from the six de- scribed species of this genus. The marginal branching and development of tertiary apical cells to the thallus margin justify the placement of this plant 1096 Bulletin of Marine Science [24( 4)

FIGURE 2. Branchioglossum prostratwn sp. nov.; A, apical tip, scale 100 J..tm; B, rhizoids emerging from thallus edge, scale 250 J..tm;C, tetrasporangial sorus, TYPE specimen, scale 500 J..tm;D, young and mature spermatangial sari, scale 250 f.Lll1. 1974] Schneider: Marine Algae from North Carolina 1097 in Branchioglossum (Kylin, 1924). The plant is, however, comparable in many respects to the plants of tenuifolium (Harvey) J. Agardh v. carolinianwn Williams which occur in deep North Carolina water (Williams, 1948, 1951). These two species have remarkably similar apical tips and comparable plant dimensions. The tetrasporangial sori are also similar; however, those in H. tenuifolium v. carolinianum are formed near the tip of young branches (Williams, 1948), while those of B. prostralum are borne randomly. These two species have been collected once from the same area. None of the previously described species exhibit a prostrate habit or as simplistic a pattern of branching as this plant. The reproductive structures of this plant bear the closest resemblance to B. woodii (J. Agardh) Kylin, as illustrated by Wagner (1954). However, the tetrasporangial sori of B. woodii are median between the midrib and the margin, as compared to the sori which are contiguous with the midrib in B. prostratum. The procarps in B. prostralum are cut off in a similar manner, but lack the curvature of those in B. woodii (Wagner, 1954). Unfortunately, the spermatangial clusters are not sufficiently discussed by Wagner (1954) to warrant com- parison. The complexity of branching and erect habit of B. woodii further justify the separation of B. prostratum as a new species. This is the first record of Branchioglossum from the Atlantic Ocean. COLLECTIONS:-No. 14577, June 23, 1970, 34°10.4'N, 76°09.6'W, depth 60 m, EEl; No. 20459, June 30, 1972, 33°28SN, 76°58.3'W, depth 60 m, E9 (Holotype DUKE #12683), <;>, is.

Memhranoptera suhtropica sp. nov. (Figs. IB,3) Thallus expansus ad 4 cm, per affixo parvo diseoideo haptero et ali- quando per secundarium affixum a multicellulosis rhizoideis ex thallo mar- gine; rami basaliter dichotomi ad subdichotomum supra, 3-4 ordinum, apices aeuti; laminae ad 1 em in latissimis locis sed plerumque minores, contractae ad furcas; monostromatae laminae ad 75 /Lm crassas, margines serrulatae; costa tenuis sed conspicua, corticata et parum e1evata penitus; venulae paucae, inconspicuae, non corticata; axiales cellulae ad 60-70 /Lm diametrum; tetrahedralis sporangia 30-75 /Lm diametro in corticatis, circu- laribus ad ovales soris a 210-220 !-tm crass is, ad 625 !-tm diametrum, medi- ani inter cost am et thallum marginem; gametangia ignota. Plant spreading to 4 cm, attached by a small discoid holdfast and occa- sional secondary attachment by multicellular rhizoids from the margin; branching basally dichotomous to subdichotomous above, af 3-4 orders, apices acute; blades to 1 cm in widest portions but usually less, tapering toward the forks; monastromatic blades to 75 !-tm thick, margins serrulate; midrib fine but conspicuous, corticated and slightly elevated throughout; 1098 [24( 4) B

o 1974] Schneider: Marine Algae from North Carolina 1099 vein lets few, inconspicuous, uncorticated; axial cells 60-70 fLm diameter; tetrahedral sporangia from 30-75 fLm diameter in corticated, circular to oval sori from 210-220 fLm thick, to 625 fLm diameter, midway between the midrib and the thallus edge; gametangia unknown. Although neither procarpic nor cystocarpic material of this alga has been found, I feel the morphological characters of it justify its placement in Mem- branoptera. This alga bears little resemblance to the other described species of this genus, especially in the fact that this is the first report of secondary attachment in this genus. Even though all the collections of this species have been by dredging, I find the habit is wide spreading, if not procumbent, as shown by the secondary attachments along some blade margins even toward their tip. Although Wynne (1970) found dentation an unreliable character in Membranoptera species, the consistency of serration in M. subtropica war- rants comparison of it only with those species that are known always or oc- casionally to possess such a margin. In comparison with its serrate counter- part from colder Atlantic waters, M. denticulata (Montagne) Kylin, M. subtropica is much less freely branched and has a less conspicuous system of venation. In addition, M. denticulata is erect and bears its tetrasporangia in special lateral blades (Taylor, 1957). Of all the dentate entities from other oceans, only M. dimorpha Gardner, from Washington, has an abun- dance of branching and branching pattern comparable to M. subtropica. The similarities, however, end there. M. dimorpha has blades from 8-14 em, and tetrasporangial sori which form along both sides of the midrib and extend nearly to the margin along the larger paired veinlets (Gardner, 1926). The shape of this plant bears very little resemblance to M. sub- tropica. The differences between all of the described dentate species and M. subtropica appear adequate for recognizing this as a new species. This is only the second report of Membranoptera from warm water. B~rgesen (1933) described M. murrayi from India. COLLECTIONS1_: No. ] 0254, Aug. ] 7, 1968, 34°1O.2'N, 76°09.2'W, depth 60 m, ED; No. 14577, June 23, 1970, 34°1O.4'N, 76°09.6'W, depth 60 m, EB (Topotypes DUKE, MICH, NCU, NFLD, NHA, TEX, UC, US, USF); No. 14578, June 23, 1970, 34° lO.4'N, 76°09.6'W, depth 60 m, EB (Holotype DUKE #12678, Isotypes DUKE); No. 17060, May 24, 1971, 34°22.9'N, 76° 35.2'W, depth 23 m, EB; No. 17663, Aug. 3, 1971, 33°31.5'N, 77°27.5'W,

1Collections refer to rock dredge stations on cruises of the R/V Eastward.

-E-

FIGURE 3. Membranoptera subtropica sp. nov.; A, thallus apex; B, rhizoids from thallus margin for secondary attachment; C, tetrasporangial sorus, TYPE specimen; D, x.s. through a tetrasporangial sorus and midrib, TYPE specimen; all scales 250 J.Lm. 1100 Bulletin ot Marine Science [24(4) depth 25 m; No. 17675, Aug. 4, 1971, 33D28.7'N, 76D58.2'W, depth 63 m; No. 20459, June 30, 1972, 33°28.5'N, 76°58.3'W, depth 60 m; No. 20467, July 1, 1972, 33D36.0'N, 76D57.7'W, depth 37 m.~

Dasyaceae Heterosiphonia wurdemanni (Bailey ex Harvey) Falkenberg v. laxa B~rgesen This find constitutes the first record of this variety from North Carolina. I have previously reported H. wurdemanni from shallower waters in this area (Schneider and Searles, 1973). The typical squarrose form and this more slender variety, although appearing similar in many respects, were thought by Falkenberg (B~rgesen, 1915) to constitute two distinct species. B~rgesen (1915), however, found the two plants too closely related to be separated on the species level and proposed the Falkenberg species be con- sidered v. typica and his slender form be called v. taxa. The plants from the glass sponge bear tetrasporangial stichidia and the squarrose plants from 30 m are sterile, just as in B~rgesen's (1915) report. Although Falkenberg suggested that v. laxa might be a deep water form, B~rgesen collected his plants from shallow water in exposed places. This variety, although more commonly reported from shallow tropical waters (Taylor, 1960), has however been reported to a depth of 51 m from the Eniwetok Atoll in Central Pacific (Gilmartin, 1960).

ACKNOWLEDGMENTS I wish to acknowledge the ship support for use of the R/Y EASTWARD provided by the National Science Foundation through grants GB-6868, GB- 17545, and GB-27725 to the Duke University Cooperative Program in Oceanography. I wish to thank Dr. Arthur Dahl for his loan of specimens and wish to express appreciation to the Farlow Herbarium for the use of its facilities. I especially thank Dr. Richard B. Searles for his assistance with the literature and the algae themselves, and his criticism of the manuscript.

LITERATURE CITED BLOMQUIST, H. L. AND H. J. HUMM 1946. Some marine algae new to Beaufort, North Carolina. Jour. Elisha Mitchell Sci. Soc., 62: 1-18. Bj2iRGESEN, F. 19]5-20. The marine algae of the Danish West Indies. Yol. 2, Rhodophy- ceae. Dansk. Bot. Arkiv., 3: 1-498, I map, 435 fig. ]933. Some Indian Rhodophyceae especially from the shores of the Presidency of Bombay, lIT. Royal Bot. Gard. Kew, Bull. Misc. Inf., 3: 113-142.

" All collections not listed. 1974] Schneider: Marine Algae from North Carolina 1101

COLLINS, F. S. AND A. B. HERVEY 1917. The algae of Bermuda. Proc. Amer. Acad. Arts and Sci., 53; 1-195, 6 pI. GARDNER, N. L. 1926. New Rhodophyceae from the Pacific coast of North America. I. Univ. Calif. Publ. Bot., 13: 205-226. GILMARTIN, M. 1960. The ecological distribution of the deep water algae of Eniwetok Atoll. Ecol., 41: 210-221. KYLlN, H. 1924. Studien Dber die Delesseriaceen. Lunds Univ. Arsskr., N.F. Avd. 2, 20(6). III pp. L'HARDY-HALOS, M. T. 1968. Les Ceramiaceae (Rhodophyceae, ) des cotes de Bretagne: 1. Le genre Antithamnion Naegeli. Rev. Algol., 2; 152-183. SCHNEIDER, C. W. AND R. B. SEARLES 1973. North Carolina marine algae. II. New records and observations of the benthic offshore flora. Phycologia, 12: 201-211. SEARLES, R. B. 1972. North Carolina marine algae. J. Three new species from the continental shelf. Phycologia, 11: 19-24. TAYLOR, W. R. 1957. Marine algae of the northeastern coast of North America. Revised ed. Univ. Michigan Press, Ann Arbor. viii + 509 p., 60 pI. 1960. Marine algae of the eastern tropic and subtropical coasts of the Americas. Univ. Michigan Press, Ann Arbor. ix + 870 p., 80 pI. WAGNER, F. S. 1954. Contributions to the morphology of the . Univ. Calif. Pub!. Bot., 27; 279-346. WILLIAMS, L. G. 1948. Seasonal alternation of marine flora at Cape Lookout, North Caro- lina. Amer. J. Bot., 35; 683-695. 1951. Algae of the black rocks. In Pearse, A. S. and L. G. Williams. The biota of the reefs off the Carolinas. Jour. Elisha Mitchell Sci. Soc., 67; 133-161. WISEMAN, D. R. ]966. A preliminary survey of the Rhodophyta of South Carolina. M.A. Thesis. Duke University. WYNNE, M. J. 1970. Marine algae of Amchitka Island (Aleutian Islands) J. Delesseriaceae. Syesis, 3; 95-144.