Electronic Flora of South Australia Genus Fact Sheet

Genus ERYTHROCLADIA Rosenvinge 1909: 71

Phylum Rhodophyta – Class Bangiophyceae – Order Compsopogonales – Family Erythrotrichiaceae

Thallus minute, epiphytic on algae, seagrasses, or on animals, consisting of prostrate, branched, radiating filaments forming a lax to compact monostromatic disc which may become 2 or 3 cells thick centrally. Marginal filaments of disc either separated and branching from subapical cells, or compact with laterally adjacent apical cells which become furcate and branch; rhodoplasts single, parietal, usually with a pyrenoid.

Reproduction: Reproduction by monosporangia cut off from cells in the central region of the disc.

Lectotype species: E. irregularis Rosenvinge 1909: 72.

Taxonomic notes: A genus of only a few species (Nichols & Lissant 1967, p. 8).

Erythrocladia was established by Rosenvinge for two species, the lectotype E. irregularis and E. subintegra. The former has relatively laxly branched radiating filaments, not all adherent to the substrate nor laterally adherent, whereas the latter forms a compact disc with a rounded growing margin of laterally adherent cells. These two species are commonly found together, and Heerebout (1968, p. 141) considered them forms of one species, apparently on the basis of variations between them and on culture experiments (without giving details). Nichols & Lissant (1967) studied E. subintegra in culture, using various media and substrates, and concluded that supposed differences between the various species of Erythrocladia were probably not valid and that most or all could come under the type species E. irregularis. The illustrations of Nichols & Lissant, however, do not include any with the form of E. irregularis. Abbott & Hollenberg (1976, p. 284) recognised both species, and Garbary et al. (1980b, p. 154) recognise them as two forms of E. irregularis.

Kornmann & Sahling (1985) maintained E. irregularis and E. subintegra not only as distinct species, but placed them in separate genera, the former in Erythrocladia and the latter in Erythropeltis Schmitz as E. subintegra (Rosenvinge) Kornmann & Sahling. The position is further complicated by the establishment of the genus Erythrotrichopeltis by Kornmann (1984), based on Bangia ciliaris Carmichael as the erect sexual phase, with Erythropeltis discigera (Berthold) Schmitz as the discoid, heteromorphic phase.

The two original Rosenvinge species of Erythrocladia are maintained below as separate species, but a more critical assessment is clearly needed.

Kornmann (1989) considers that the morphology and growth patterns of E. irregularis and E. subintegra are so different that they cannot be regarded as co-generic, and he places E. subintegra in a new genus Sahlingia.

References:

ABBOTT, I.A. & HOLLENBERG, G.J. (1976). Marine Algae of California. (Stanford Univ. Press: Stanford.)

GARBARY, D.J., HANSEN, G.I. & SCAGEL, R.F. (1980b). The marine algae of British Columbia and northern Washington: Division Rhodophyta (red algae), Class Bangiophyceae. Syesis 13, 137–195.

HEEREBOUT, G.R. (1968). Studies on the Erythropeltidaceae (Rhodophyceae - Bangiophycidae). Blumea 16, 139–157.

KORNMANN, P. & SAHLING, P.-H. (1985). Erythropeltidaceen (Bangiophyceae, Rhodophyta) von Helgoland. Helgoländer Meeresunters. 39, 213–236.

KORNMANN, P. (1984). Erythrotrichopeltis, eine neue Gattung der Erythropeltidaceae (Bangiophyceae, Rhodophyta). Helgoländer Meeresunters. 38, 207–224.

KORNMANN, P. (1989). Sahlingia nov. gen. based on Erythrocladia subintegra (Erythropeltidales, Rhodophyta). Br. phycol. J. 24, 223–228.

NICHOLS, H.W. & LISSANT, E.K. (1967). Developmental studies of Erythrocladia Rosenvinge in culture. J. Phycol. 3, 6–18.

ROSENVINGE, L.K. (1909). The marine algae of Denmark. Part 1. Introduction. Rhodophyceae. 1. (Bangiales and Némalionales). K. danske Vidensk. Selsk. Biol. Skr., 7 Raekke, Afd. 7, 1–151, Plates 1, 2,2 maps.

The Marine Benthic Flora of Southern Australia Part IIIA complete list of references.

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (14 January, 1994)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIA, Bangiophyceae and Florideophyceae (to Gigartinales)
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIA 1994, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

KEY TO SPECIES OF ERYTHROCLADIA

1. Thallus forming an irregular disc, with filaments not all laterally adherent and branching from submarginal cells

E. irregularis

1. Thallus forming a compact disc with a more or less entire margin and with filaments laterally adherent; marginal cells often furcate

E. subintegra


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