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Heterosiphonia microcladioides (J. Agardh) Falkenberg 1901: 637, pl. 19 fig. 5.

Phylum Rhodophyta – Order Ceramiales – Family Dasyaceae

Selected citations: De Toni 1903: 1224. Lucas 1912: 158. Lucas & Perrin 1947: 316.


Dasya microcladioides J. Agardh 1890a: 83.

Dasya pellucida sensu Harvey 1855a: 543; 1859b: 304; 1863, synop. xxiv. Sonder 1881: 36. (NON Harvey 1847: 67, pl. 27 lower left.)

Thallus (Fig. 219A) medium to dark red-brown, tufted, 2–6 cm high, with several erect axes, ecorticate, more or less complanately branched, arising from prostrate axes. Attachment by rhizoids; epizoic or epiphytic on seagrass or algae. Structure. Apices of axes and lateral branches sympodial and distichous (Fig. 219B), developing 7–8 pericentral cells beginning 5–10 cel Is below the apices, mature segments 150–350 µm in diameter and L/D 0.4–1.2 (–2). Pseudolaterals (2–) 4–7 segments apart (Fig. 219B), 1.5–3 mm Jong, becoming polysiphonous below but with simple (occasionally branched) terminal filaments of 6–12 (–20) cells, lower segments 100–130 µm in diameter and L/D 0.5–0.8, tapering markedly to subapical cells 35–90 µm in diameter and L/D 0.5–1. Pseudolaterals with adaxial and distichous branches, usually with a secondary sympodial axis arising adaxially on the fourth (occasionally third) segment from their base, and with the primary branch of the pseudolateral extending in length and becoming hamate, cells 100–140 µm across and L/D 0.5–1. Attachment rhizoids arising from cells of pseudolaterals, with multicellular haptera. Rhodoplasts discoid, in chains in larger cells.

Reproduction: Gametophytes unknown, apart from Falkenberg's (1901, p. 638) description of procarps as arising on the third segment below the fourth segment bearing the secondary lateral symposium.

Tetrasporangial stichidia (Fig. 219C–E) developing from a polysiphonous branch of the pseudolaterals, (350–) 500–1500 µm long and 100–180 µm in diameter, lanceoid to cylindrical with a short polysiphonous pedicel and short blunt apex, occasionally continuing growth with a simple or branched filament (Fig. 219E); tetrasporangia 5 per segment, each with 2 pre-sporangial cover cells which divide horizontally giving 4 squat cells covering each sporangium.

Lectotype from Port Phillip Heads, Vic. (Wilson, 4.ii.1889); in Herb. Agardh, LD, 43617.

Selected specimens: King George Sound, W. Aust. (Harvey, Tray. Set 308, as Dasya pellucida, in TCD). Port Turton, Yorke Pen., S. Aust., 8–10 m deep (Kald, 5.ix.1970; AD, A37264). Vivonne Bay, Kangaroo I., S. Aust., in shaded eulittoral pool (Womersley, 15.i.1947; AD, A4469). Young Rocks, S of Kangaroo I., S. Aust., on bryozoan, 16–30 m deep (Branden, 18.vi.1991; AD, A61462). Swan I., Port Phillip, Vic., 0–0.5 m deep on barge (Womersley, 8.iv.1959; AD, A22600). Popes Eye, Port Phillip Heads, Vic., on bryozoans, 10 m deep (Watson, 3.xii.1983; AD, A55418). Crawfish Rock, Westernport Bay, Vic., 3–6 m deep (Watson, 15.ix.1968; AD, A32793) and 6m deep (Shepherd, 31.i.1970; AD, A35264). Gabo I., Vic., 28 m deep (Shepherd, 14.ii.1973; AD, A43355). Low Head, Tas. (Perrin, April 1940; AD, A8965). Satellite I., D'Entrecasteaux Ch., Tas., 0–2 m deep (Shepherd, 17.ii.1972; AD, A41655).

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

Taxonomic notes: Distribution: King George Sound, W. Aust., to Gabo I., Vic., and around Tasmania.


AGARDH, J.G. (1890a). Till algernes systematik. Acta Univ. lund. 26(3), 1–125, Plates 1–3.

DE TONI, G.B. (1903). Sylloge Algarum omnium hucusque Cognitarum. Vol. 4. Florideae. Sect. 3, pp. 775–1521 + 1523–1525. (Padua.)

FALKENBERG, P. (1901). Die Rhodomelaceen des Golfes von Neapel und der angrenzenden Meeres-abschnitte. Fauna und Flora des Golfes von Neapel. Monogr. 26. (Friedlander: Berlin.)

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

HARVEY, W.H. (1859b). Algae. In Hooker, J.D., The Botany of the Antarctic Voyage. III. Flora Tasmaniae. Vol. II, pp. 282–343, Plates 185–196. (Reeve: London.)

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

LUCAS, A.H.S. & PERRIN, F. (1947). The Seaweeds of South Australia. Part 2. The Red Seaweeds. (Govt Printer: Adelaide.)

LUCAS, A.H.S. (1912). Supplementary list of the marine algae of Australia. Proc. Linn. Soc. N.S.W. 37, 157–171.

SONDER, O.W. (1881). In Mueller, F., Fragmenta Phytographiae Australiae. Supplementum ad volumen undecinum: Algae Australianae hactenus cognitae, pp. 1–42, 105–107. (Melbourne.)

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

Illustration in Womersley Part IIIA, 1998: FIG. 219.

Figure 219 image

Figure 219   enlarge

Fig. 219. Heterosiphonia microcladioides (A, AD, A32793; B, AD, A22600; C, D, AD, A43355; E, AD, A35264). A. Habit. B. Axis with polysiphonous pseudolaterals 3-5 segments apart. C. Branch with stichidia. D. A stichidium. E. Stichidium with branched apical filament.

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