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Electronic Flora of South Australia Species Fact Sheet

Audouinella daviesii (Dillwyn) Woelkerling 1971: 28, figs 7,22; 1973b: 550, figs 32–43.

Phylum Rhodophyta – Class Florideophyceae – Order Acrochaetiales – Family Acrochaetiaceae

Selected citations: Dixon & Irvine 1977b: 90, fig. 22. Garbary 1987: 54. Garbary et al. 1983: 19, fig. 6. Millar 1990: 299, fig. 4A, B. Millar & Kraft 1993: 6. Schneider & Searles 1991: 200, fig. 235.


Conferva daviesii Dillwyn 1802–1809: 73.

Acrochaetium daviesii (Dillwyn) Nägeli 1861: 405. Levring 1953: 476.

Colaconema daviesii (Dillwyn) Stegenga 1985: 317, fig. 20.

Callithamnion radicans Harvey 1855a: 563; 1863, synop.: lvi.

Acrochaetium radicans (Harvey) J. Agardh 1892: 48. Levring 1953: 477, fig. 10E–G.

Acrochaetium villiforme Levring 1953: 481, figs 15D, E, 16, 17.

Thallus (Fig. 9A, B) medium red to purple-brown, usually epiphytic, caespitose, usually 2–8 mm high; original spore non-persistent. Prostrate system (Fig. 9B) consisting of an epiphytic pseudoparenchymatous disc or an entangled endophytic funiform mass. Erect filaments (Fig. 9A) sparsely to freely and irregularly branched, sometimes slightly attenuate, ending in multicellular, almost colourless, hair-like prolongations. Cells (Fig. 9D) of main axes and laterals cylindrical, (8.5–) 10–17 (–24) µm in diameter and (17–) 30–50 (–90) µm long, LID (1.5–) 2–4 (–6.5), sometimes tapering to 2.5–10 µm in diameter and 20–75 µm long (L/D up to 30) near the apices; each cell containing a single parietal band shaped to lobed rhodoplast (Fig. 9D) with a single (rarely two) prominent pyrenoid.

Reproduction: Monosporangia (Fig. 9C, D) ovoid, 8–13 µm in diameter and (12–) 16–20 (–24) µm long, in clusters of 4–8 on branched stalks and sometimes also singly or in pairs on 1–2-celled stalks, situated on the lowermost cells of laterals or sometimes scattered or terminal.

Thallus apparently dioecious. Carpogonia (Fig. 9E) terminal on unicellular stalks; immediate post-fertilization stages unknown. Mature carposporophyte (Fig. 9F) consisting of branched gonimoblast filaments bearing terminal ovoid carposporangia 8–10 µm in diameter and 16–20 µm long. Spermatangia (Fig. 9G) ovoid to spherical, 2–3 µm in diameter 3–4 µm long, borne terminally or laterally in dense clusters or occasionally in smaller groups on branched stalks.

Tetrasporangia (Fig. 9H) ovoid to subglobose, (13–) 15–18 µm in diameter and 17–21 µm long, cruciately divided, borne in pairs or clusters on unicellular stalks or occasionally solitary, on the lowermost cells of laterals or sometimes scattered.

Type from Ireland or Wales (Swansea) (see Woelkerling 1973b, pp. 552, 594; Dixon & Irvine 1977b, p. 90); lectotype in BM.

Selected specimens: Port Denison, W. Aust., on Amphibolis antarctica, upper sublittoral (Woelkerling, 8.xi.1968; AD, A32921). Cottesloe, W. Aust., on Ecklonia radiata, upper sublittoral (Woelkerling, 14.xi.1968; AD, A32926). Fremantle, W. Aust., on "Zostera" (prob. Posidonia) (Harvey, 1854; AD, A18536, isotype of Callithamnion radicans Harvey). Point Peron, W. Aust., on Amphibolis sp., upper sublittoral (Mitchell, 22.ix.1966; AD, A30732). Head of the Great Australian Bight, S. Aust., on Ecklonia radiata, drift (Woelkerling, 4.xi.1968; AD, A32924). Venus Bay, S. Aust., on Amphibolis sp., drift (Womersley, 12.ii.1954; AD, A19503). Daly Head, S. Aust., on Lenormandia spectabilis, drift (Gordon, 26.iii.1967; AD, A31287). Marino, S. Aust., on Posidonia sp., drift (Womersley, 21.v.1953; AD, A18644). Pennington Bay, Kangaroo I., S. Aust., on Polycerea nigrescens, drift (Womersley, 7.i.1948; AD, A6499, isotype of Acrochaetium villiforme Levring). Stanley Beach, Kangaroo I., S. Aust. on Lenormandiopsis latifolia, drift (Womersley, 7.ii,1956; AD, A20097). Port Elliot, S. Aust., on Amphibolis antarctica, upper sublittoral (Woelkerling, 28.vii.]967; AD, A32239). Robe, S. Aust., on A. antarctica, upper sublittoral (Womersley, 26.viii.1973; AD, A43935 -"Marine Algae of southern Australia" No. 153). Cape Bridgewater. Vic., on Chaetomorpha aerea in high-level shaded pool (Womersley, 21.viii.1953; AD, A19056). Burraneer, N.S.W. (Levring, 16.xi.1947; AD, A19854).

Distribution map based
on current data relating to
specimens held in the
State Herbarium of SA

Distribution: Almost cosmopolitan.

In southern Australia, from Port Denison, W. Aust., to Cape Bridgewater, Vic., and to Coffs Harbour, N.S.W. (probably more widespread), on a wide variety of algae, marine angiosperms, and marine invertebrates.

Taxonomic notes: Audouinella daviesii is one of the commoner species of Audouinella, characterised by its habit, dimensions (though the filament diameters vary between different populations) and in particular by the lateral groups of monosporangia on branched stalks. Other species of similar habit (e.g. A. saviana) have solitary (rarely paired), sessile (or on unicellular stalks) monosporangia. A. daviesii usually occurs in the upper sublittoral in southern Australia but has been recorded from the lower eulittoral and from depths of 10 m.

Few records of sexual populations are known: one is from Western Australia (AD, A32853), one from South Australia (AD, A6499, isotype of Acrochaetium villiforme Levring), and a few from North America (Woelkerling 1973b, p. 553).


AGARDH, J.G. (1892). Analecta Algologica. Acta Univ. lund. 28, 1–182, Plates 1–3.

DILLWYN, L.W. (1802–1809). British Confervae. (Phillips: London.)

DIXON, P.S. & IRVINE, L.M. (1977b). Seaweeds of the British Isles. Vol. 1, Rhodophyta. Part I, Introduction, Nemaliales, Gigartinales. [British Museum (N.H.): London.]

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.

HARVEY, W.H. (1855a). Some account of the marine botany of the colony of Western Australia. Trans. R. Ir. Acad. 22, 525–566.

HARVEY, W.H. (1863). Phycologia Australica. Vol. 5, Plates 241–300, synop., pp. i-lxxiii. (Reeve: London.)

LEVRING, T. (1953). The marine algae of Australia. I. Rhodophyta: Goniotrichales, Bangiales and Némalionales. Arkiv för Bot. Ser. 2, 2, 457–530.

MILLAR, A.J.K. & KRAFT, G.T. (1993). Catalogue of Marine and Freshwater Red Algae (Rhodophyta) of New South Wales, including Lord Howe Island, South-western Pacific. Aust. Syst. Bot. 6, 1–90.

MILLAR, A.J.K. (1990). Marine Red Algae of the Coffs Harbour Region, northern New South Wales. Aust. Syst. Bot. 3, 293–593.

NÄGELI, C. (1861). Beitrage zur Morphologie and Systematik des Ceramiaceae. Sber. bayer. Akad. Wiss. Jb., 1861, 1, 297–415, Plate 1.

SCHNEIDER, C.W. & SEARLES, R.B. (1991). Seaweeds of the Southeastern United States. (Duke Univ. Press: Durham.)

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.

WOELKERLING, W.J. (1973b). The morphology and systematics of the Audouinella complex (Acrochaetiaceae, Rhodophyta) in northeastern United States. Rhodora 75, 529–621.

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

Author: W.J. Woelkerling & 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.

Illustration in Womersley Part IIIA, 1994: FIG. 9 A–H.

Figure 9 image

Figure 9   enlarge

Fig. 9. A–H. Audouinella daviesii (A–D, H, AD, A31287; E, F, AD, A6499; G, AD, A30732). A. Upper erect filaments with monosporangia. B. Prostrate system with bases of erect filaments. C. Clusters of monosporangia. D. Filament with a cluster of monosporangia and cells with rhodoplasts and a single pyrenoid. E. Branch with carpogonia on unicellular stalks. F. Mature carposporophyte. G. Branch with spermatangia. H. Branch with tetrasporangia. I–K. Audouinella phacelorhiza (AD, A32925). I. Branching pattern, with prostrate system between utricles of Codium. J. Erect filaments with monosporangia, some with thickened apical walls. K. Cells with rhodoplasts and single pyrenoids. [B, C, E–H, K after Woelkerling 1971.]

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