Electronic Flora of South Australia Species Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Acrochaetiales – Family Acrochaetiaceae
Selected citations: Garbary 1987: 172.
Rhodochorton simplex Drew 1928: 165, pl. 37 figs 4–11.
Acrochaetium pectinatum (Kylin) Hamel sensu West 1968: 89, figs 1–28.
Audouinella pectinata (Kylin) Papenfuss sensu Woelkerling 1971: 24, figs 2,3.
Thallus (Fig. 8D) epiphytic, 0.5–2 (–3) mm high, with densely massed erect filaments; original spore usually persisting as a more or less globular, thick-walled, unicellular holdfast (in sexual plants - Fig. 8F) 7–14 µm in diameter, giving rise to (1–) 2–3 (–5) sparsely branched erect filaments; tetrasporophytes developing a basal system of coalescing filaments (Fig. 8E). Main axes (Fig. 8D) slightly branched, with laterals irregularly arranged, sometimes approaching the main axis in length, simple or bearing a few irregularly to fasciculately arranged branchlets. Cells (Fig. 8F–J) cylindrical, 3–6 µm in diameter and 5–40 µm long, L/D (1–) 3–6 (–9); each cell containing a parietal, lobate to stellate to spirally twisted rhodoplast (Fig. 8I) which may become dissected into several portions; pyrenoids absent. Terminal and pseudolateral hairs (Fig. 8G) up to 100 µm long occur rarely.
Reproduction: Monosporangia (Fig. 8G, H) ovoid, 5–7 (–10) µm in diameter and 8–15 (–18) µm long, sessile or 1–2 (–3) on unicellular stalks or occasionally in clusters of 4–10 on branched stalks, scattered over the erect filaments.
Thallus monoecious or dioecious. Spermatangia (Fig. 8J) ovoid, 2–3 µm in diameter and 3–4 µm long, borne singly or in pairs in terminal or lateral clusters on branched stalks or singly or in pairs on 1–2-celled stalks.
Other reproductive structures unknown in southern Australian collections. [Tetrasporangia and female plants reported by West (1968) and Garbary et al. (1983, p. 53)].
Type from Santa Monica, California, U.S.A.; holotype in UC, 276666.
Selected specimens: Port Elliot, S. Aust., on Diciyopteris nigricans (Woelkerling, 31.i.1968; AD, A32233, 1.iii.1968; AD, A32249, and 3.iv.1968; AD, A32259).
Distribution: Pacific coast of N. America; South Africa? (Stegenga 1985, p. 314). In southern Australia, recorded from Port Elliot, S. Aust.
Taxonomic notes: This species was recorded as Audouinella pectinata by Woelkerling (1971, p. 24), but Garbary et al. (1983, p. 51) considered the southern Australian collections referable to A. simplex and not A. pectinata (Kylin) Papenfuss from Europe. They are provisionally referred to A. simplex but the life history has not been studied and only monosporangial and male plants are known. Both unicellular and pseudoparenchymatous basal systems occur, and the male plants are about 0.5 mm high, considerably taller than those (50–130 µm high) recorded by West (1968, p. 95) who found that the life history is heteromorphic with sexual plants usually less than 500 µm high and with unicellular bases, and tetrasporophytes 1–20 mm high with pseudoparenchymatous bases.
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. (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.
STEGENGA, H. (1985). The marine Acrochaetiaceae (Rhodophyta) of southern Africa. S. Afr. J. Bot. 51, 291–330.
WEST, J.A. (1968). Morphology and reproduction of the red alga Acrochaetium pectinatum in culture. J. Phycol. 4, 89–99.
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. 8 D–J.
Figure 8 enlarge
Fig. 8. A–C. Audouinella secundata (A, B, AD, A21725; C, AD, A19846). A. Branching pattern, with prostrate system and erect filaments with monosporangia. B. Upper branches with monosporangia. C. Cells with rhodoplasts and a monosporangium. D–J. Audouinella simplex (D, E, I, AD, A32249; F–H, J, AD, A32233). D. Branching pattern, with unicellular base, erect filaments and monosporangia. E. Prostrate system of (presumed) tetrasporophyte. F. Basal cell and lower filaments of gametophyte. G, H. Filaments with stalked monosporangia. I. Cells (all from one filament) showing variation in rhodoplast form. J. Branch with spermatangia. [F–J after Woelkerling 1971.]
State Herbarium of South Australia