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Electronic Flora of South Australia Species Fact Sheet

Dasyclonium flaccidum (Harvey) Kylin 1956: 534.

Phylum Rhodophyta – Family Rhodomelaceae – Tribe Polyzonieae

Selected citations: Adams 1994: 315. Scagel 1962: 1024, figs 4, 32–34. Huisman 1997: 203. Huisman & Walker 1990: 433. Huisman et al. 1990: 97. Kendrick et al. 1990: 52. Shepherd & Womersley 1981: 368. Silva et al. 1996: 487. Yoshida 1998: 1020.


Polyzonia flaccida Harvey 1855a: 539; 1858: pl. 42B; 1863, synop.: xv. J. Agardh 1863: 1165. Sonder 1880: 31. Tisdall 1898: 513. Wilson 1892: 166.

Euzoniella flaccida (Harvey) Falkenberg 1901: 365, pl. 5 fig. 10. De Toni 1903: 1029. Lucas 1909: 44. Lucas & Perrin 1947: 288, fig. 134. May 1949: 296; 1965: 379. Scagel 1953: 81. Womersley 1950: 189.

Dasya archeri Harvey 1859b: 304. J. Agardh 1863: 1197; 1890: 83. Parsons & Womersley 1998: 479.

Heterosiphonia archeri (Harvey) De Toni 1903: 1219.

Thallus (Fig. 140A) medium to dark red-brown, basally attached to host (or rock?), above free and 1–15 cm long; indeterminate axes irregularly branched and bearing distichous, alternate, determinate laterals (0.6–) 1–2 mm long from each second segment (Fig. 140B); determinate laterals pectinate (Fig. 140B, C), main branch usually curved downwards, complanately branched with simple, exogenous branches from each second cell, these branches with monosiphonous ends 5–12 cells long or sometimes entirely monosiphonous. Lateral indeterminate axes arising endogenously from a segment above a determinate lateral, separated usually by 3 determinate laterals, occasionally developing into longer axes. Attachment by rhizoids; epiphytic on various algae, occasionally epilithic. Structure. Apex slightly curved, apical cells dome-shaped, 15–30 µm in diameter. Indeterminate axes with 6 pericentral cells, 130–350 µm in diameter, segments L/D 0.4–1. Determinate laterals below with 3 pericentral cells, 60–150 µm in diameter below with segments L/D 0.4–1.2; pericentral cells L/D (1.5–) 2–3, monosiphonous parts 35–100 µm in diameter with cells L/D 1–5, end cell mucronate. Trichoblasts apparently absent. Rhizoids usually in pairs from adjacent axial pericentral cells, not cut off, with digitate haptera. Cells uninucleate, larger cells multinucleate; rhodoplasts discoid to slightly elongate.

Reproduction: Female plants unknown. Spermatangial organs (Fig. 140D) tri-radiate, developed from the lower parts of determinate lateral branches, with a single basal and 3–5 apical sterile segments 150–600 µm long and 130–230 µm across, each flange with a marginal row of isodiametric sterile cells.

Tetrasporangial branches (Fig. 140E) arising endogenously from the segment above each determinate lateral, curved upwards towards the axis and developing short cellular outgrowths; tetrasporangia in series of 4–6, 80–140 µm in diameter, with 3 (divided) cover cells.

Lectotype from King George Sound, W. Aust. (Harvey); lectotype Trav. Set 34 in Herb. Harvey, TCD.

Selected specimens: 7 mile Beach, N of Dongara, W. Aust., on Amphibolis, drift (Womersley, 17.ix.1979; AD, A51354). Port Denison, W. Aust., drift (Kraft 4005, 14.xii.1971; AD, A41713). Safety Bay, W. Aust. on Amphibolis, drift (Womersley, 18.viii.1979; AD, A50789). 4 km W of Waldegrave I., S. Aust., 30 m deep on limestone (Branden, 3.vii.1987; AD, A57583). Elliston, S. Aust., on Distromium multifidum, 7 m deep (Shepherd, 21.x.1970; AD, A37581) and on Husseya, 5 m deep (Shepherd, 24.x.1973; AD, A44282). Pearson Is, S. Aust., epiphytic, 48 m deep (Shepherd, 9.i.1969; AD, A33713). Daly Head, Yorke Pen., S. Aust., drift (Woelkerling, 26.iii.1967; AD, A31407). Aldinga, S. Aust., on Sargassum, drift (Womersley, 17.ix.1966; AD, A30713). Victor Harbor, S. Aust., sublittoral (Engler, 8.v.1979; AD, A63179). Vivonne Bay, Kangaroo I., S. Aust., on Myriodesma?, drift (Womersley, 1.i.2000; AD, A68408). Penneshaw, Kangaroo I., S. Aust., on Heterozostera, 6 m deep (Lavers, 8.i.1997; AD, A66868). Robe, S. Aust., on Sargassum, drift (Womersley, 20.xii.1953; AD, A19113). Currie R., N Tas., on fucoid (Perrin, Jan. 1938; AD, A10158). Bridport, Tas., on Cystophora grevillei, drift (Womersley, 23.x.1986; AD, A57788).

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

Distribution: Houtman Abrolhos, W. Aust., to Robe, S. Aust., and N Tasmania. Japan.

Taxonomic notes: The type of Dasya archeri Harvey (1859b, p. 304), from Georgetown, Tas. (Archer), in Herb. Harvey, TCD, is Dasyclonium flaccidum, the determinate lateral branches having frequent monosiphonous ends.

Dasyclonium flaccidum is a variable species as considered by Harvey and other authors, especially in the monosiphonous ends to the branches of the determinate laterals which vary from almost the complete length to only the terminal 2 or 3 cells. Nearly all specimens can be separated from D. incisum on the characters used in the key, but occasional intermediate plants occur. Further study is warranted.


ADAMS, N.M. (1994). Seaweeds of New Zealand. (Cant. Univ. Press: Christchurch.)

AGARDH, J.G. (1863). Species Genera et Ordines Algarum. Vol. 2, Part 3, pp. 787–1291. (Gleerup: Lund.)

AGARDH, J.G. (1890). 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. (Friedländer: 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. (1858). Phycologia Australica. Vol. 1, Plates 1–60. (Reeve: London.)

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.)

HUISMAN, J.M. & WALKER, D.I. (1990). A catalogue of the marine plants of Rottnest Island, Western Australia, with notes on their distribution and biogeography. Kingia 1, 349–459.

HUISMAN, J.M. (1997). Marine Benthic Algae of the Houtman Abrolhos Islands, Western Australia. In Wells, F.E. (Ed.) The Marine Flora and Fauna of the Houtman Abrolhos Islands, Western Australia, pp. 177–237. (W. Aust. Museum: Perth.)

HUISMAN, J.M., KENDRICK, G.A., WALKER, D.I. & COUTÉ, A. (1990). The Marine Algae of Shark Bay, Western Australia. Research in Shark Bay. Report of the France-Australe Bicentenary Expedition Committee, pp. 89–100.

KENDRICK, G.A., HUISMAN, J.M. & WALKER, D.I. (1990). Benthic macroalgae of Shark Bay, Western Australia. Bot. Mar. 33, 47–54.

KYLIN, H. (1956). Die Gattungen der Rhodophyceen. (Gleerups: Lund.)

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

LUCAS, A.H.S. (1909). Revised list of the Fucoideae and Florideae of Australia. Proc. Linn. Soc. N.S.W. 34, 9–60.

MAY, V. (1949). Studies on Australian marine algae. IV. Further geographical records. Proc. Linn. Soc. N.S.W. 73, 293–297.

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

PARSONS, M.J. & WOMERSLEY, H.B.S. (1998). Family Dasyaceae Kützing 1843: 413, 414 in Womersley H.B.S. The Marine Benthic Flora of southern Australia. Part IIIC. State Herbarium of South Australia, 422–510.

SCAGEL, R.F. (1953). A morphological study of some dorsiventral Rhodomelaceae. Univ. Calif. Pubis Bot. 27, 1–108.

SCAGEL, R.F. (1962). The genus Dasyclonium J. Agardh. Canadian J. Bot. 40, 1017–1040, Plates i-iv.

SHEPHERD, S.A. & WOMERSLEY, H.B.S. (1981). The algal and seagrass ecology of Waterloo Bay, South Australia. Aquat. Bot. 11, 305–371.

SILVA, P.C., BASSON, P.W. & MOE, R.L. (1996). Catalogue of the Benthic Marine Algae of the Indian Ocean. (Univ. California Press: Berkeley.)

SONDER, O.W. (1880). In Mueller, F., Fragmenta Phytographiae Australiae. Supplementum ad volumen undecinum: Algae Australianae hactenus cognitae, pp. 1–42, 105–107. (Melbourne.)

TISDALL, H.T. (1898). The algae of Victoria. Rep. 7th Meet. Aust. Ass. Adv. Sci., Sydney, 1898, pp. 493–516.

WILSON, J.B. (1892). Catalogue of algae collected at or near Port Phillip Heads and Western Port. Proc. R. Soc. Viet. 4, 157–190.

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

YOSHIDA, T. (1998). Marine Algae of Japan. (Uchida Rokakuho Publ. Co.: Tokyo.)

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

Publication: Womersley, H.B.S. (24 February, 2003)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIID. Ceramiales – Delesseriaceae, Sarcomeniaceae, Rhodomelaceae
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIID 2003, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

Illustration in Womersley Part IIIA, 2003: FIG. 140.

Figure 140 image

Figure 140   enlarge

Fig. 140. Dasyclonium flaccidum (A, D, AD, A57583; B, C, AD, A44282; E, AD, A57788). A. Habit. B. Indeterminate branch with pectinate determinate laterals with monosiphonous branches. C. Detail from B. D. Triradiate spermatangial organs. E. Tetrasporangial branches arising from segments above determinate laterals.

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