Electronic Flora of South Australia Species Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Acrochaetiales – Family Acrochaetiaceae
Selected citations: Garbary et al. 1983: 39, fig. 16.
Rhodochorton plumosum Drew 1928: 173, p1. 39 fig. 29. Nakamura 1944: 108, figs 6, 7.
Colaconema plumosum (Drew) Woelkerling 1971: 48, fig. 18. Stegenga 1985: 323, fig. 23.
Thallus (Fig. 11A) epiphytic, caespitose, 200–1000 µm high. Prostrate system (Fig. 11A, C) consisting of creeping, branched filaments more or less confluent in the centre. Erect filaments (Fig. 11A, B) moderately branched, laterals opposite, alternate, or secund and tending to lie in one plane. Cells (Fig. 11B, D) cylindrical or occasionally fusiform, (5–) 8–12 (–17) µm in diameter and 18–36 µm long (L/D 1.5–4) in lower portions of main axes, gradually tapering to 2–4 µm in diameter near the apices; each cell containing a single parietal rhodoplast (Fig. 11D) and one pyrenoid. Terminal and pseudolateral hairs up to 250 µm long occur.
Reproduction: Monosporangia (Fig. 11B, D) ovoid, 3–8 µm in diameter and 6–12 µm long, mostly opposite and more or less distichous along the main axes and laterals, sessile or stalked; contents of subtending vegetative cells sometimes developing into monosporangia after release of the terminal monospore.
Other reproductive structures unknown.
Type from Fort Point, San Francisco, California, U.S.A.; holotype in UC, 294559 (Gardner 4441).
Selected specimens: Port Elliot, S. Aust., on Petalonia fascia, upper sublittoral (Woelkerling, 8.ix.1967; AD, A31279). Crawfish Rock, Westernport Bay, Vic., on Porphyra lucasii, just sublittoral (Watson, 15.ix.1968; AD, A32707).
Distribution: California; Pacific Mexico; Japan; South Africa.
In southern Australia, known from Port Elliot, S. Aust., and Westernport Bay, Vic.
Taxonomic notes: Australian specimens of Audouinella plumosa are similar to the type (from Drew's illustration) but are less than 1 mm high, in contrast to "several millimetres".
A. pacifica and A. plumosa share a number of features, but they apparently differ in the width of erect filaments, arrangement of laterals, and arrangement of sporangia and are maintained as distinct species for the present. Abbott & Hollenberg (1976, p. 315) however treated A. plumosa as a synonym of A. pacifica.
ABBOTT, I.A. & HOLLENBERG, G.J. (1976). Marine Algae of California. (Stanford Univ. Press: Stanford.)
DREW, K.M. (1928). A revision of the genera Chantransia, Rhodochorton, and Acrochaetium with descriptions of the marine species of Rhodochorton (Naeg.) gen. emend. on the Pacific Coast of North America. Univ. Calif. Pubis Bot. 14, 139–224, Plates 37–48.
GARBARY, D.J. (1979b). Numerical Taxonomy and generic circumscription in the Acrochaetiaceae (Rhodophyta). Bot. Mar. 22, 477–492.
GARBARY, D.J. (1987). The Acrochaetiaceae (Rhodophyta): An annotated bibliography. Bibl. Phycol. 77, 1–267.
GARBARY, D.J., HANSEN, G.I. & SCAGEL, R.F. (1983). The marine algae of British Columbia and northern Washington: Division Rhodophyta (red algae), Class Florideophyceae, Orders Acrochaetiales and Nemaliales. Syesis 15 (suppl.), 1–102.
NAKAMURA, Y. (1944). The species of Rhodochorton from Japan. II. Sci. Pap. Inst. Algol. Res. Fac. Sci. Hokkaido Imp. Uni. 3, 99–119.
STEGENGA, H. (1985). The marine Acrochaetiaceae (Rhodophyta) of southern Africa. S. Afr. J. Bot. 51, 291–330.
WOELKERLING, W.J. (1971). Morphology and taxonomy of the Audouinella complex (Rhodophyta) in southern Australia. Aust. J. Bot. Suppl. 1, 1–91.
The Marine Benthic Flora of Southern Australia Part IIIA complete list of references.
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.
Illustration in Womersley Part IIIA, 1994: FIG. 11 A–D.
Figure 11 enlarge
Fig. 11. A–D. Audouinella plumosa (AD, A31279). A. Branching pattern, with prostrate system and erect branches with monosporangia. B. Erect branches with distichous laterals and monosporangia, and hairs. C. Prostrate system with bases of erect branches. D. Cells each with a rhodoplast and pyrenoid, with young monosporangia. E–I. Audouinella pacifica (E, F, H, >I,G, AD, A30884). E. Young thallus with prostrate system and erect branches. F. Erect filament with monosporangia. G. Erect filament with monosporangia and a hair. H. Upper branch with a tetrasporangium. I. Cells each with a rhodoplast and pyrenoid. [B, C, F–H after Woelkerling 1971.]
State Herbarium of South Australia