Electronic Flora of South Australia Species Fact Sheet

Dasya clavigera (Womersley) Parsons 1975: 585, figs 7–9A, B, 40B.

Phylum Rhodophyta – Order Ceramiales – Family Dasyaceae

Selected citations: Shepherd & Womersley 1976: 190.

Synonym

Dasyopsis clavigera Womersley 1946: 137, figs , pl. 27; 1950: 182. May 1965: 380. Shepherd & Womersley 1971: 166.

Thallus (Fig. 209A, B) dark red-brown, occasionally paler, slightly mucilaginous, with 1–2 (–4) axes, pyramidal in form, (1–) 3–15 (–60) cm high, axes simple or rarely branched with robust laterals radially or occasionally bilaterally arranged and 2–10 (–25) cm long, densely covered with pseudolaterals but often basally denuded. Main axes heavily corticated, 1–2 (–3) mm in diameter, percurrent, branched at intervals of 0.5–2 cm. Laterals 2–10 (–20) cm long; axes 400–800 µm in diameter, moderately corticated from close to their apices, arising from the basal cell of the fourth branching of the young pseudolateral. Adventitious laterals common in older parts, arising from surface cortical cells near the base of normal laterals, singly or in clumps. Holdfast 2–10 mm across, with one to several erect axes; epilithic or often epiphytic on larger algae. Structure. Pericentral cells 5, becoming obscured in older axes (Fig. 210B) or laterals by profuse development of rhizoids. Pseudolaterals one per segment (Fig. 210A), spirally arranged, 1–1.5 (–2) mm long, the filaments increasing in diameter and length from the basal cell until a few cells after the last subdichotomy, then tapering to a slenderer filament which is often broken off but may have an acute apical cell; basal subdichotomies 3–7, every 1–2 (–3) cells, giving 25–40 ultimate branches; basal and lower cells 40–80 µm in diameter, L/D (0.5–) 1–2, mid and upper cells 55–100 µm in diameter and L/D 2–3 (–4). Adventitious monosiphonous filaments absent. Rhodoplasts discoid to elongate, becoming chained and reticulate.

Reproduction: Gametophytes dioecious. Procarps (Fig. 210C) alternating on the adaxial side of the second, third and fourth segments of the secondary sympodial axes on pseudolaterals. Carposporophyte with a basal fusion cell, gonimoblast much branched, carposporangia ovoid to subspherical, 15–25 µm in diameter, borne singly or in rows of 2–4. Cystocarps (Fig. 209C) sessile on corticated laterals, urceolate, 800–1200 (–1400) µm in diameter, with a prominent corticated neck 0.2–0.5 as long as the cystocarp diameter; pericarp 4–5 cells thick, outer cells ovoid, irregularly placed. Spermatangial branches (Figs 209D, 210D, E) on the lower branches of the pseudolaterals, sessile or on a 1–2-celled monosiphonous stalk, 120–200 µm long and 40–45 (–50) µm in diameter with 7–10 fertile segments, terminated by a short, 1–5-celled, apical filament.

Stichidia (Figs 209E, 210F) on lower branches of the pseudolaterals, lanceoid to cylindrical, on a 1–2 (–3)-celled monosiphonous stalk and with a short apical filament, 200–400 (–450) µm long and 80–150 µm in diameter with usually 8–15 fertile segments each with 6 pericentral cells (Fig. 210G, H) all of which become fertile. Tetrasporangia 30–40 µm in diameter each with 2–3 rather swollen cover cells covering 0.5–0.8 of the sporangium and dividing rarely.

Type from Pennington Bay, Kangaroo I., S. Aust., on eastern edge of main reef (Womersley, 15.i.1946); holotype in AD, A2845; isotypes in AD, MEL, NSW. Paratypes: S side of Ellen Point, Vivonne Bay, Kangaroo I., S. Aust., lower eulittoral (Womersley, 23.v.1945; AD, A2726; MEL, 1006636, and 31.xii.1945; AD, A2997; MEL, 1006637).

Selected specimens: Hopetoun, W. Aust., drift (Parsons, 20.xi.1968; AD, A33355). Third Beach, Esperance, W. Aust., drift (Burbidge, Jan. 1936; AD, A5811). Point Sinclair, S. Aust., lower eulittoral (Womersley, 7.ii.1954; AD, A19857). Pearson I., S. Aust., 5–12m deep (Shepherd, 8.i.1969; AD, A34093). Elliston, S. Aust., lower eulittoral outer reef (Parsons, 16.v.1968; AD, A32561). Wanna, S. Aust., drift (Womersley, 19.ii.1959; AD, A22395). Port Elliot, S. Aust., on Amphibolis, upper sublittoral (Parsons, 3.xi.1967; AD, A32067). Robe, S. Aust., upper sublittoral (Womersley; 5. xii.1995; AD, A64772). Stinky Bay, Nora Creina, S. Aust., upper sublittoral ( Womersley, 6.xii.1995; AD, A64758-"Marine Algae of southern Australia" No. 178a). Port MacDonnell, S. Aust., upper sublittoral (Parsons, 11.ii.1968-"Marine Algae of southern Australia" No. 178). Port Fairy, Vic. (Harvey, Alg. Aust. Exsicc. 208D; AD, A18207). Queenscliff, Vic., drift (Womersley, 8.iv.1959; AD, A22867). Cat Bay, Phillip I., Vic., drift (Womersley, 10.iv.1959; AD, A22716).

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

Distribution: Hopetoun, W. Aust. to Westernport Bay, Vic., and the east coast of Tasmania, epilithic or epiphytic (mainly on larger brown algae) in the lower eulittoral or upper sublittoral on rough-water coasts, fertile throughout the year.

Taxonomic notes: D. clavigera has been described in detail by Parsons (1975, p. 585, figs 7–9A, B, 40B). It and D. naccarioides are the only species which grow just above and below low tide level, on rough-water coasts, and it differs from D. naccarioides in the abrupt ending to most pseudolateral branches and in having 6 tetrasporangia per whorl instead of 5.

References:

MAY, V. (1965). A census and key to the species of Rhodophyceae (red algae) recorded from Australia. Contr. N.S.W. natn. Herb. 3, 349–429.

PARSONS, M.J. (1975). Morphology and taxonomy of the Dasyaceae and Lophothalieae (Rhodomelaceae) of the Rhodophyta. Aust. J. Bot. 23(4), 549–713.

SHEPHERD, S.A. & WOMERSLEY, H.B.S. (1971). Pearson Island Expedition 1969.7. The subtidal ecology of benthic algae. Trans. R. Soc. S. Aust. 95(3), 155–167.

SHEPHERD, S.A. & WOMERSLEY, H.B.S. (1976). The subtidal algal and seagrass ecology of St Francis Island, South Australia. Trans. R. Soc. S. Aust. 100, 177–191.

WOMERSLEY, H.B.S. (1946). Studies on the marine algae of southern Australia No. 2. A new species of Dasyopsis (Family Dasyaceae) from Kangaroo Island. Trans. R. Soc. S. Aust. 70(2), 137–144.

WOMERSLEY, H.B.S. (1950). The marine algae of Kangaroo Island. III. List of Species 1. Trans. R. Soc. S. Aust. 73, 137–197.

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

Author: M.J. Parsons and H.B.S. Womersley

Publication: Womersley, H.B.S. (24 December, 1998)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIC. Ceramiales – Ceramiaceae, Dasyaceae
©State Herbarium of South Australia, Government of South Australia

Illustrations in Womersley Part IIIA, 1998: FIGS 209, 210.

Figure 209   enlarge

Fig. 209. Dasya clavigera (A, AD, A2845; B–E, AD, A64758). A. Holotype sheet (upper) with lower Vivonne Bay specimens. B. Habit. C. Young cystocarp with darkly stained fusion and vegetative cells. D. Spermatangial branches. E. Stichidia. (A, as in Womersley 1946, courtesy of R. Soc. S. Aust.)

Figure 210   enlarge

Fig. 210. A–H. Dasya clavigera (AD, A32560). A. Mature pseudolateral showing about half the branches. B. Transverse section of mature axis. C. Procarps on a sympodial axis. D. Spermatangial branches. E. Transverse section of spermatanigal branch. F. Stichidia. G. Transverse section of a stichidium. H. Apex of a stichidium. (All as in Parsons 1975, courtesy of Aust. J. Bot.) I. Dasya quadrispora (AD, A57011). Transverse section of a stichidium.

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