from the Pacific coast of North America

Phycologia (2000) Volume 39 (4), 323-331

Published 30 November 2000

Corallophila eatoniana comb. nov. (Ceramiaceae, Rhodophyta) from the

Pacific coast of North America T.O. CHOI, H.-G. CHarI, G. H ANSEN2 AND S.M. Bool* IDepartment of Biology, Chungnam National University, Daejon 305-764, Korea 2Hatfield Marine Science Center, Oregon State University, Oregon, USA

TO. CHO, H.-G. CHOl, G. HANSEN AND S.M. Boo. 2000. Corallophila eatoniana comb. nov. (Ceramiaceae, Rhodophyta) from the Pacific coast of North America. Phyc%

gia 39: 323-331.

A new combination is proposed for plants previously referred to as Ceramium eatonianum (Farlow) De Toni [= Centroceras eatonianum Farlow 1875] (Ceramiaceae, Rhodophyta). This red algal species is transferred to the genus Corallophila mostly on the basis of the following characteristics. It has rhizoids that arise from periaxial and inner cortical cells, outer cortical cells that are rectangular and arranged in longitudinal rows, spermatangia that develop on ordinary cortical cells, and tetrasporangia that are covered by cortical cells. Corallophi/a eatoniana is further characterized by having uniseriate rhizoids, pinnate branches. six to eight (usually seven) periaxial cells at the nodes, large gland cells on the tips of acropetal cortical filaments, and tetrasporangia on the upper parts of regular branches. The species occurs on the Pacific coast of North America from British Columbia, Canada, to Baja California, Mexico. Corallophila eatoniana is here neotypified by a specimen collected at Seal Rock, Oregon, on 10 July 1998. Generic comparisons between Corallophila and the fully corticated species of Ceramium and Centroceras are also given.

INTRODUCTION

Corallophila Weber-van Bosse (Ceramiaceae, Rhodophyta) was established to receive a new species, C. kleiwegii, col lected from Nias Island near Sumatra (Weber-van Bosse 1923). She mentioned that Corallophila was similar to Cer amium Roth but that it could be distinguished from Ceramium by having tetrasporangia on stichidia and from Reinboldiella De Toni by having rectangular cortical cells regularly arranged in longitudinal rows. Although the genus has been accepted and used by several phycologists (e.g. Price & Scott 1992), the taxonomic circumscription of the genus is still controver sial. Norris (1993) brought tetrasporangial and spermatangial features to light that could be used to separate the above three genera and added nine species to Corallophila: one species was transferred from Ceramiella B!2lrgesen, two from Centro ceras Kiitzing, and six from Ceramium. Recently, Yoshida

(1998) and Abbott (1999) have listed the species of Corallo phila from Japan and Hawaii, respectively. Centroceras was segregated from Ceramium by Kiitzing (1841) for species having spines and a characteristic cortica tion pattern. Farlow (1875) described C. eatonianum from ma terial collected in Oregon and California that had a pinnate habit, instead of dichotomous branches, and segments desti tute of spines. A type specimen was not designated. De Toni (1903), following J. Agardh (1894), did not accept Kiitzing's segregate genera and transferred Centroceras eatonianum to Ceramium. Kylin (1941) treated the species as belonging to Centroceras, along with C. clavulatum (c. Agardh) Mon tagne. Smith (1944), while recognizing Centroceras for C. clavulatum, retained eatonianum in Ceramium, and subse quent authors have followed his treatment (Doty 1947; Daw son 1962; Abbott & Hollenberg 1976). *

Corresponding author ([email protected]).

Ceramium eatonianum has been reported from British Co lumbia, Canada, to Baja California, Mexico (Smith 1944; Dawson 1950, 1962; Norris & West 1966; Abbott & Hollen berg 1976). Although the species is common in the intertidal zone over its geographical range, there have been few studies on the detailed morphology and taxonomy of the species. Based on collections from the Pacific coast of North America attributed to C. eatonianum, we are able to confirm the generic concept of CoraZZophila as revised by Norris (1993), and we now propose the transfer of Ceramium eatonianum to Cor allophila.

MATERIAL AND METHODS

All specimens were initially observed for morphology while alive and were then preserved in 5% formalin-seawater for further anatomical observations. The liquid-preserved speci mens were dehydrated in 25% ethyl alcohol solution, dissect ed with a fine razor by hand under a dissecting microscope, and then stained with 1% aniline blue in water. Developmental sequences of the vegetative and reproductive cells were fol lowed by gently squashing material mounted in 30% glycerine after treatment with a drop of 2% hydrochloric acid. Photo micrographs were taken through an Olympus microscope (VANOX AHBT 3) and drawings were obtained by using a camera lucida. For quantitative features, 25 measurements were used whenever possible for obtaining mean values. Her barium specimens from AD, FH, NY, PC, SAp, and UC were compared with our collections (herbarium abbreviations fol low Holmgren et al. 1990). Voucher specimens are deposited in the herbaria at the Department of Biology, Chungnam Na tional University, Daejon, Korea, and the Hatfield Marine Sci ence Center, Oregon State University, Newport, Oregon, USA. 323

324

Phycoiogia, Vol. 39 (4), 2000 (Emily Wood, personal communication) and Uc. We therefore designate a specimen (Fig. 44) collected at Seal Rock near Newport, Oregon, on 10 July 1998 as the neotype of Corallophila eatoniana in accordance with Article 9.11 of the International Code of Botanical Nomenclature (Greuter et at. 1994). This specimen, other collections of C. eatoniana from Washington and northern California, and herbarium specimens borrowed from PC, SAp, and UC all corresponded to the protologue (Farlow 1875). DISTRIBUTION:

British Columbia, Canada, to Baja California,

Mexico. SPECIMENS EXAMINED: USA: Friday Harbor, Washington, 3-5 cm high (16 July 1998; Herbarium of Chungnam National University, C00206-C00208, vegetative); Seal Rock, Oregon, 4-7 cm high (10 July 1998; Herbarium of Chungnam National University, C00041-C00042, tetrasporangial and C00043C00045, C00212, C002 13, vegetative); Cape Lookout (south side), Oregon, 4-6.5 cm high (6 September 1998; Herbarium of Chungnam National University, COOI93-COOI95 and C00209C00211, vegetative); Santa Cruz, California (May 1885; PC, number not given, tetrasporangial; collection date not given, UC 687856, tetrasporangial); Pescadero Pt., Monterery Peninsula, 8 cm high, epiphytic on Coraltina sp. (AD, A47541); Bodega Bay, California, 6.5 cm high (28 August 1998; Herbarium of Chungnam National University, COOI27, vegetative); Berkeley Yacht Harbour, on rip-rap at entrance from San Francisco Bay ( 17 December 1968; UC, herbarium number not given, tetrasporangial). MEXICO: Punta San Rosario, Baja California, 4.5 cm high (9 April 1946; SAp, 053570, female) and 2.4 cm high (9 April 1946; SAp, 053569, tetrasporangial); Punta San Rosario, Baja California (13 April 1946; SAp, 053563 and 053565, tetrasporangial); Rio San Telmo, Baja California, 5.3 cm high (13 January 1946; SAp, 053566, male); Cabo, Colonet, Baja California (13 January 1946; SAp, 053567, tetrasporangial); El Cardon, Punta Maria, Baja California, 7.2 cm (14 April 1946; SAp, 053564, tetrasporangial). REPRESENTATIVE

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Abbreviations in Figs 1-43. AC, apical cell; Ax, axial cell; C, cys tocarp; C1-C4, cortical initials; Ft, foot cell; Fu, fusion cell; G, goni moblast; GC, gland cell; GIl , primary gonimolobe; GI2, second gon imolobe; OC, out cortical cell; p, periaxial cell; pG, primary goni moblast; IC, inner cortical cell; Rh, rhizoid; SMC, spermatangial mother cell; Sp, spermatangia; Su, supporting cell; T, tetrasporangia.

Figs 1-11. Corallophila eatoniana. Fig. 1. Vegetative thallus. Fig. 2. Upper thallus with dichotomous branches. Fig. 3. Upper thallus with alternate branches. Figs 4-9. Sequence of formation of periaxial cells from an axial cell.

Fig. 10. Formation of the inner and outer cortical cells from per iaxial cells. Fig. 11. Formation of rhizoids from inner cortical cell.

RE SULTS

Corallophila eatoniana (Farlow) Cho, Choi, Hansen & Boo, comb. nov.

Figs 1-44 BASIONYM:

Centroceras eatonianum Farlow 1875: 373.

HOMOTYPIC SYNONYM:

Ceramium eatonianum (Farlow) De Toni

1903: 1493.

Centroceras oregonense J. Agardh 1876: 107 (according to De Toni 1903, p. 1493). Ceramium zebrinum J. Agardh 1894: 37 (according to Doty 1947, p. 187). HETEROTYPIC SYNONYMS:

NEOTYPIFICATION: We designate as neotype specimen C00044 (Fig.

44), collected at Seal Rock near Newport, Oregon, USA, on 10 July 1998 and deposited in the herbarium of the Department of Biology, Chungnam National University, Daejon, Korea. According to Farlow (1875), the material used for the protologue of Centroceras eatonianum was collected in Oregon by Mr E. Hall, but a type specimen was not actually designated. Doty (1947, p. 187) lectotypified C. eatonianum with the Hall collection in Oregon in 187 1, which was probably from the northernmost part of Oregon, in Clatsop County. However, the material referred to in the protologue is missing from both the Farlow Herbarium at Harvard

Habitat and phenology

Corallophila eatoniana often occurs in the mid- to upper in tertidal zone, frequently in exposed habitats subjected to wave action. It often forms small mounds, with sand bound between its filaments. Occasionally it is epiphytic on coralline algae and other seaweeds. Vegetative morphology HABIT: Plants are purplish-brown and adhere to paper on dry ing. They generally form loose tufts (Fig. 1) and are 3.5-8 cm [5.2 ± 1.0 cm (mean ± s), n = 20] tall. The apex is slightly incurved (Figs 2, 3, 38). AXIS AND RHIZOlDS: The thalli consist primarily of erect axes with prostrate axes anchored by filamentous rhizoids. The rhi zoids are formed in groups from the inner cells and are re stricted to the dorsal side of the nodes. They are rod-shaped, uniseriate (Fig. 11), and usually 3-5 cells in length, with a blunt apex. The erect axis is composed of the axial cell row, periaxial cells, inner cortical cells, and cortical outer cells (Fig. 10). The axis is 290 ± 37 JJ.m (n = 10) wide at the level of the seventh branch from the apex. AXIAL AND PERlAXIAL CELL DEVELOPMENT: The axial cell row is formed by transverse division of the apical cell. The axial cells are spherical to cylindrical, 330 ± 14 JJ.m long, and 240 ± 29 JJ.m wide (n = 18) at the level of the seventh branch from apex, making the length: width ratio 1.2-1.6 : 1. Periaxial cells are produced from the subapical axial cells. They are cut off obliquely from the upper part of each parent axial cell and remain at the nodes after elongation. The first periaxial cells

Cho et al.: Corallophila eatoniana comb. nov.

325

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Figs 12-21. Corallophila eatoniana. Figs 12-16. Early stages in the formation of a cortical unit, composed of cortical cells, from a single periaxial cell. Fig. 17. Middle stage in the formation of a cortical unit. Figs 18-19. A mature cortical unit. Basipetal cortical filaments predominate, with rectangular cells and linear cell rows. Fig. 20. Young axis covered with cortical cells, with internodal spaces (arrows). Fig. 21. Mature axis covered with cortical cells, with internodal spaces (arrows). The basipetal cortical cells are rectangular and regularly arranged in longitudinal rows.

are formed on the abaxial side of the second to fourth axial cells. Five to seven periaxial cells are then cut off in an al ternating sequence, first to one and then to the other side of the first periaxial cell (Figs 4-9). DEVELOPMENT OF THE CORTEX: The cortex is composed of inner and outer cortical cells. It covers the axial cells at the tips of the filaments, leaving very narrow internodal spaces (Figs 20, 21, 39, 40), while the axial cells below this are completely corticated. The inner cortical cells are large and spherical. They occur only at the nodes and consist of a single layer covered by the cortical cells (Figs 18, 19). The first cortical initial cell is formed from the first periaxial cell on its abaxial side before the other periaxial cells develop. The cortical cells at the nodes are spherical, compact, 14 ::':: 2 ].Lm long, and 13 ::':: 2

].Lm in diameter, while the cortical cells in the internode are rectangular, loose, regularly arranged in longitudinal rows, 57 ::':: 11 ].Lm long, and 16 ::':: 3 ].Lm in diameter (Figs 18, 19, 40). The cortex develops from four cortical initials that are cut off in an alternating sequence from each periaxial cell. These initials then each form four corticating filaments (Figs 12-16). The first two initials are cut off obliquely from the anterior end of the periaxial cell, and the next two are cut off trans versely from the posterior end. The anterior initials branch dichotomously, forming ascending filaments 4-6 (5.2 ::':: 1.2, n = 14) cells long (Figs 19, 21). The posterior initials produce a pair of descending filaments, which continue to grow down ward as a result of the transverse division of the terminal cells, becoming 14-17 (16 ::':: 1.4, n = 14) cells long (Figs 19, 21). The downward growth of the descending filaments keeps pace

326

Phycoiogia, Vol. 39 (4), 2000

SMC

22 300 iJIIl 23 24 25 25 j.QD

Figs 22-25. Corallophila eatoniana. Fig. 22. Thallus-bearing spermatangia. Fig. 23. Spermatangial mother cells divided from cortical cells. Fig. 24. Surface of spermatangial thallus. Fig. 25. Cross section of spermatangial thallus.

with the elongation of the axial cell (Figs 19, 21). Each per iaxial cell produces two descending filaments. GLAND CELL: Gland cells are elliptical, 31 ± 5 f-l.m long, and 25 ± 4 f-l.m in diameter. They are terminally formed from cortical cells at the tips of the acropetal corticating filaments at each node by oblique division (Figs 16, 17).

Branches are repeatedly dichotomous to alternate and usually divide in the same plane. When a branch is produced, the apical initial first divides obliquely, cutting off a small cell on the inside of the dichotomy. This cell functions as the apical cell of the main axis and the large cell on the opposite side functions as the apical cell of the lateral branch. Branches are formed at in tervals of 6-10 (7.2 ± 1.0) cells in the main branches and 69 (7.1 ± 0.7) cells in lateral branches (Fig. 1). Occasionally, adventitious branches develop in the lower thallus and occa sionally in the upper thallus. Unlike normal branches, adven titious branches develop from periaxial cells and are small and curved. BRANCHING PATTERNS AND THEIR DEVELOPMENT:

Reproductive morphology OF SPERMATANGIA: Spermatangia occur on the cortical cells of the upper thallus, forming a cushion over the whole surface (Figs 22, 24, 41). The cortical cells each cut off four to six spermatangial mother cells (Fig. 23). Sperma tangial mother cells then elongate and become rod-shaped, cutting off one or two spermatangia terminally by oblique divisions (Fig. 25). Spermatangia are colourless, spherical, and measure 2.5 ± 0.4 f-l.m X 2.7 ± 0.4 f-l.m (n = 13). DEVELOPMENT

Cystocarps occur along the abaxial sides of the upper axis (Fig. 30). They are naked withDEVELOPMENT OF CYSTOCARPS:

out involucral branches and are composed of two or three gonimolobes (Figs 29, 42). They are typically 373 ± 61 f-l.m long and 285 ± 31 f-l.m in diameter. The supporting cell pro duces the auxiliary cell, apparently after fertilization. The aux iliary cell then divides into a foot cell and the primary goni moblast cell. The foot cell fuses with the axial cell (Fig. 26) and then with the tiny supporting cell, forming a large fusion cell (Fig. 27). The first gonimolobe initial is cut off from the upper third of the primary gonimoblast cell (Fig. 26). Later, one or two secondary gonimolobes are cut off from the sides of the gonimoblast, with the resulting gonimoblast consisting of two or three gonimolobes (Fig. 27). The gonimolobe cells are mostly transformed into carposporangia at maturity (Fig. 28).

DEVELOPMENT OF TETRASPORANGIA: Tetrasporangial plants are distinguishable by having apices that are slightly reflexed.

Tetrasporangia are distributed in the upper thallus (Figs 31, 43). They are produced from the first-formed periaxial cells on the abaxial face of the axis and then develop in an alter nating sequence on the other periaxial cells (Figs 32-35). Oc casionally, they also originate from the inner cortical cells of the nodes (Figs 36, 37). Tetrasporangia are completely im mersed in the cortex or, occasionally, are partially exposed (Figs 35, 36). They are spherical to ellipsoidal in shape and measure 80 ± 9 f-l.m X 66 ± 8 f-l.m, excluding the sheath, and 93 ± 8 f-l.m X 79 ± 8 f-l.m including it. Division of the tetras porangium is simultaneous and results in four tetrahedrally arranged spores (Fig. 34). Tetrasporangia occur on regular branches, and there were no tetrasporangial stichidia in our material.


327

Figs 26-30. Corallophila eatoniana. Figs 26-28. Postfertilization process after division of the auxiliary cell to give a foot cell and a primary gonimoblast. Fig. 29. Cystocarp without involucral branches. Fig. 30. Fertile branch of a female plant with cystocarps.

DISCUSSION

Genera belonging to the red algal tribe Ceramieae have been reported on most coasts of the world. During the latter part of the 1900s, their circumscriptions were gradually modified (Dixon 1960; Hommersand 1963; Maggs & Hommersand 1993; Boo & Lee 1994; Athanasiadis 1996). Members having predominantly basipetal growth of corticating filaments were placed in the genera Centroceras, Ceramiella, Ceramium, and also Corallophila, although Corallophila has not been rec ognized for some time. Table 1 indicates that Corallophila has diagnostic features that clearly separate it from the related genera, Ceramium and Centroceras. The characteristics of C. eatoniana found in the present study support the generic con cept of Corallophila established by Weber-van Bosse (1923) and revised by Norris (1993). Rhizoidal development is an important feature for distin guishing genera within this tribe. In Centroceras, rhizoids arise from periaxial cells only (Hommersand 1963; Boo & Lee 1985), whereas they arise from periaxial and/or inner and/or outer cortical cells in Ceramium (Dixon 1960; Boo & Yoon 1993) and from periaxial and/or inner cortical cells in Cor-

allophila. They develop from the inner cortical cells in C. eatoniana, from the periaxial and inner cortical cells in C. verongiae (Ballantine & Wynne) Norris, and from the periax ial cells in C. apiculata (Yamada) Norris (Centroceras api culatum Yamada: Ardre 1987), C. itonoi (Ardre) Norris (Cer amium itonoi Ardre: Ardre 1987), and C. cinnabarina (Gra teloup ex Bory de Saint Vincent) Norris [Ceramium cinna barium (Grateloup ex Bory de Vincent) Hauck: Ardre et al. 1982]. Corallophila is further distinguished from Centroceras and Ceramium by the shape, orientation, and arrangement of the cortical cells in the internode. The cortical cells of Corallo phila are rectangular, grow predominantly in a basipetal di rection, and are regularly arranged in longitudinal rows (We ber-van Bosse 1923; Kylin 1956). Norris (1993, figs 1, 2) further made it clear that four corticating filaments are pro duced from each periaxial cell in Corallophila. Corallophila is very similar to Centroceras in cortical cell shape and ori entation, but three corticating filaments are produced from each periaxial cell in Centroceras. In Ceramium, the cortical cells are ovoid to angular, grow simultaneously in both the acropetal and basipetal direction, and are irregularly arranged

328


Figs 31-37. Corallophila eatoniana. Fig. 31. Thallus-bearing with slightly reftexed tips. Figs 32-34. Formation of tetrasporangia from periaxial cells. Fig. 35. Surface of thallus-bearing tetrasporangia developed from periaxial cells. Fig. 36. S urfa ce of thallus-bearing tetrasporangia developed from periaxial and inner cortical cells. Fig. 37. Longitudinal section of tetrasporangial thallus showing tetrasporangia formed from both the periaxial cells and inner cortical cells.

along the axis (Hommersand 1963; Boo & Lee 1994). Fur thermore, three or five corticating filaments are produced from each periaxial cell in Ceramium. Spermatangia in Corallophila develop on all the cortical cells of the upper thallus, covering the whole surface. In this feature, Corallophila is very similar to Ceramium (Hommer sand 1963; Boo & Yoon 1993). In Centroceras, spermatangia are produced on the upper ends of the periaxial cells and are limited to the nodal regions (Hommersand 1963). Norris (1993) included development of spermatangia on the cortical cells as a key character for Coraliophila. Our observations of cystocarp development in Corallophila eatoniana are the first for this genus. Most of the postfertil ization stages of C. eatoniana are similar to those in fully corticated Ceramium species (Hommersand 1963; Boo & Yoon 1993). However, the mature cystocarps lack involucral branches, as reported by Smith (1944, for Ceramium eaton ianum). Naked cystocarps also occur in Corallophiia huys-

mansii (Weber-van Bosse) R.E. Norris (Norris 1993) and ap pear to be distinctive for the genus Coraliophila, since the cystocarps of Ceramium and Centroceras are protected by in volucral branches originating from periaxial cells. However, the taxonomic value of this trait should be confirmed after cystocarps in the remaining members of Corallophila have been observed. Tetrasporangia provide additional diagnostic features for the genera. In Coraliophila, they are almost completely embedded in the cortex. The tetrasporangia are formed from periaxial cells and occasionally inner cortical cells, and they occur only at the nodes. In the corticated members of Ceramium, most tetrasporangia are completely immersed in the cortex, but they are dispersed along the axis (Hommersand 1963; Boo & Yoon 1993). In Centroceras, tetrasporangia are formed from periax ial cells and exserted from the cortex (Hommersand 1963; Boo & Lee 1985; Norris 1993). According to Norris (1993), tetrasporangia mostly covered by outer cortical cells are di-


329

39

43

I

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Figs 38-43. Corallophila eatoniana. Scale bars = 100 J.Lm Fig. 38. Habit of C. eatoniana, collected in Santa Cruz in May 1885. Fig. 39. Young axis covered with cortical cells with internodal spaces (arrows). Fig. 40. Mature axis covered with cortical cells with internodal spaces (arrows). The basipetal cortical cells are arranged in longitudinal rows. Fig. 41. Male plant with spermatangia. Fig. 42. Female plant with cystocarps. Fig. 43. Tetrasporangial plant with tetrasporangia.

agnostic for Corallophila. Weber-van Bosse (1923) adopted stichidial tetrasporangia as a generic feature, but this feature is variable (Norris 1993) and is not present in C. eatoniana. Although Corallophila is intermediate between Ceramium and Centroceras in some features, the genus is distinctive in hav ing rhizoids formed from periaxial to inner cortical cells, rect angular cortical cells that are regularly arranged in longitu dinal rows and grow basipetally, spermatangia that occur on outer cortical cells, naked cystocarps, and tetrasporangia that are mostly covered by outer cortical cells. These features are summarized in Table 1. Worldwide, there are 11 known members of Corallophila,

including the type species, C. kleiwegii (Norris 1993; this study). Most of these species have not been well studied; lim ited information is available on their morphology and less is known of their reproduction. However, C. eatoniana does ap pear to be distinguishable from other Corallophila species by the following features: pinnate branches, uniseriate rhizoids developing from inner cortical cells at the nodes, gland cells on the tips of acropetal corticating filaments, six to eight (usu ally seven) periaxial cells, and tetrasporangia occurring on regular branches. This species is distributed from cold to sub tropical waters along the Pacific coast of North America, from Washington, USA, to Baja California, Mexico (Farlow 1875;

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Kyung Chul Park helped with a wide variety of things during TOC's stay in Oregon. 5MB thanks Prof. H.B.S. Womersley in Adelaide, Dr Fran�oise Ardre in Paris, and Prof. Michio Masuda and Dr Kazuhiro Kogame in Sapporo for hospitality in accessing herbarium specimens. We are very grateful to Prof. Paul C. Silva and Dr Richard L. Moe for access to the UC herbarium specimens, providing specimens on loan, and Emily Wood, for detailed information on Farlow's material. 5MB and HGC's work is supported by KOSEF. We are very grateful to Drs Alan Millar, Richard Moe, and Athanasios Athanasiadis for many suggestions and comments improving our paper.

REFERENCES

Neolectotypus, CoraUophila eatoniana (Farlow) Designated by Cho, Choi, Hansen et Boo Herbarium of Chungnam National University Department of Biology in Daejon (Korea) C

OOO4 (sheet 4 number), Seal Rock, Oregon, USA, 10. Vii. 1998,

Collected by T.O. Cho & G. Hansen

Fig. 44. The neotype specimen of Corallophila eatoniana (Farlow) Cho, Choi, Hansen & Boo.

Dawson 1962). Other Corallophila members occur along sub tropical to tropical coasts in Australia, Indonesia, and Hawaii (Price & Scott 1992; Norris 1993).

ACKNOWLEDGEMENTS

TOC thanks Mr Todd Miller for transportation from Oregon to California and for helping with collections in California. Drs Mike Foster in Monterey, California, Richard Steele in Washington, and John Gerke in Tillamook, Oregon, provided hospitality and information on collection sites. In addition, Mr

ABBOTT l.A. 1999. Marine red algae of the Hawaiian Islands. Bishop Museum Press, Honolulu, Hawaii. 477 pp. ABBon I.A. & HOLLENBERG G.J. 1976. Marine algae of California. Stanford University Press, California. 827 pp. AGARDH J.G. 1876. Species genera et ordines algarum. Volumen ter tium: de Florideis airae posteriores, part 1. Weigel, Leipzig. 724 pp. AGARDH J.G. 1894. Analecta algologica. Continuatio II. Lunds Uni versitets A rsskrift 30: 1-99. ARDRE F. 1987. Observations sur quelques especes du genre Centro ceras (Ceramiaceae, Rhodophyta). Cryptogamie, Algologie 8: 281300. ARDRE F., L' H ARDY-HALOS M.-T. & SALDANHA L. 1982. Observations nouvelles sur la morphologie et la repartition geographique de trois Ceramiales: Ceramium cinnabarinum, Mesothamnion caribaeum et Ctenosiphonia hypneoides. Cryptogamie, Algologie 3: 3-20. ATHANASIADIS A. 1996. Morphology and classification of the Cera mioideae (Rhodophyta) based on phylogenetic principles. Opera Botanica 128: 1-216. Boo S.M. & LEE I.K. 1985. Two Korean species of Centroceras Kiitz ing (Ceramiaceae, Rhodophyta). Korean Journal of Botany 28: 297-304. Boo S.M. & L EE I.K. 1994. Ceramium and Campylaephora (Cera miaceae, Rhodophyta). In: Biology of economic algae (Ed. by I. Akatsuka), pp. 1-33. SPB Academic Publishing, The Hague, The Netherlands. Boo S.M. & YOON H.S. 1993. Systematic studies of Ceramium kondoi (Ceramiaceae, Rhodophyta) in the field and in culture. Korean Jour nal of Phycology 8: 179-189. DAWSON E. Y. 1950. A review of Ceramium along the Pacific coast of north America with special reference to its Mexican representatives. Farlowia 4: 113-138.

Table 1. A comparison of fully corticated Ceramium, Centroceras and Corallophila.

References Habit Rhizoids Inner cortical cells Internodal cortical cells Corticating filaments or cells Growth of cortical cells Arrangement of cortical cells Spermatangia Cystocarps Tetrasporangia Distribution

Ceramium

Centroceras

Corallophila

(Dixon 1960; Hommersand 1963; Boo & Lee 1994)

(Hommersand 1963; Boo & Lee 1985)

(Weber-van Bosse 1923; Norris 1993; this study)

prostrate and erect axes from periaxial, inner cortical or outer cortical cells well developed along axis ovoid to angular 3-5 per periaxial cell acropetal and basipetal irregular on cortical cells with involucral branches immersed cosmopolitan

prostrate and erect axes from periaxial cells only absent rectangular 3 per periaxial cell mostly basipetal in regular longitudinal rows on periaxial cells with involucral branches exserted cosmopolitan

prostrate and erect axes from periaxial and inner cortical cells developed at nodes rectangular 4 per periaxial cell mostly basipetal in regular longitudinal rows on cortical cells without involucral branches immersed SE Asia and northwestern America

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Accepted 20 May 2000