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Electronic Flora of South Australia Species Fact Sheet

Polysiphonia succulenta Harvey 1859b: 300; 1863, synop.: xx.

Phylum Rhodophyta – Family Rhodomelaceae – Tribe Polysiphonieae

Selected citations: J. Agardh 1863: 968. De Toni 1903: 879. Garnet 1971: 97. Guiler 1952: 103. Lucas 1909: 41; 1929a: 21. Lucas & Perrin 1947: 267. Segi 1966: 513, pl. 24B. Shepherd & Womersley 1971: 166. Silva et al. 1996: 546. Sonder 1880: 34. Tisdall 1848: 514. Womersley 1950: 185; 1956: 82, 83; 1979: 485, fig. 7A–D.


Polysiphonia spinuligera Zanardini 1874: 490. De Toni 1903: 955. Guiler 1952: 103. Lucas 1909: 41; 1929a: 22. Lucas & Perrin 1947: 271. Tisdall 1898: 514. Wilson 1892. 167.

Thallus (Fig. 83A) grey-brown to red-brown, usually 5–12 (–20) cm high with a single erect base and lower axis, branching subdichotomously (to laterally) to form a dense, fastigiate to spreading tuft. Holdfast of clumped rhizoids from lower cells of erect axes; epiphytic, usually on Posidonia australis. Structure. Lower axes (400–) 500–1000 µm in diameter with segments L/D 0.2–0.5; rhizoids unicellular and cut off from the pericentral cells; branches above the basal axis 300–500 µm in diameter with segments L/D (0.5–) 0.8–1 (–1.5) decreasing gradually to 100–200 µm in diameter with segments L/D 0.3–0.8 close to the apices, then tapering fairly abruptly to pointed apices which are commonly slightly to markedly involute (Fig. 83C, D) and usually have a prominent apical cell; lateral branches developing close to apices, replacing trichoblasts, with occasional cicatrigenous branchlets from lower parts. Pericentral cells 4 (often 5 within 2–5 segments from base of a lateral branch), isodiametric near apices (Fig. 83B) and extending to twice (rarely 3 times) L/D below, ecorticate except for slight cortical development near the base in robust plants by elongate cells cut off laterally or from the corners of pericentral cells, never forming a complete layer; older cells not readily permeable (partially collapsing in Karo); trichoblasts or scar cells present on every segment, with a divergence of 1/4, trichoblasts relatively robust, basally several times furcate, with long, tapering ultimate branches 4–6 cells long. Rhodoplasts discoid to elongate and often in chains, irregularly arranged.

Reproduction: Gametophytes dioecious. Carposporophytes with a slight basal fusion cell and short, branched gonimoblast with clavate terminal carposporangia 25–60 µm in diameter. Cystocarps (Fig. 83B) short-stalked, globular to slightly ovoid, occasionally slightly urceolate, (300–) 400–700 µm in diameter; pericarp ostiolate, 2 cells thick, with the terminal ostiolar cells distinctly enlarged when mature, outer cells isodiametric, angular. Spermatangial branches (Fig. 83C) usually developing as one (rarely both) basal branch of a trichoblast with the sterile branch soon lost, sometimes replacing whole trichoblast, elongate-ovoid, 150–300 µm long and (60–) 100–180 (–200) µm in diameter, usually with a sterile dome-shaped apical cell and often a sterile subapical cell or single sterile cell borne laterally on the subapical cell.

Tetrasporangia (Fig. 83D) forming spiral series of 1/4 divergence in upper branches (often extending below a lateral), not or slightly distorting or swelling the branch, 80–120 µm in diameter.

Type from Georgetown, Tas. (Gunn); holotype in Herb. Harvey, TCD; isotype in BM, part of holotype.

Selected specimens: Cockburn Sound, W. Aust., on Posidonia australis (Cambridge, 10.v.1972; AD, A47070). Lucky Bay, Cape le Grand, W. Aust., on P. australis, upper sublittoral (Woelkerling, 30.i.1978; AD, A49267). Billy Light Point, Port Lincoln, S. Aust., on P. australis, 4 m deep (Shepherd, 23.viii.1975; AD, A46554). Muston, American R. inlet, Kangaroo I., S. Aust., on P. australis, 2–3 m deep (Womersley, 21.xi.1968; AD, A32930-"Marine Algae of southern Australia" No. 127, and Kraft, 2.xii.1971; AD, A41197). San Remo backbeach, Vic., drift (Sinkora A536, 14.vi.1970: MEL, 504847, AD, A49488). "Seaweed Point", Tamar Est., Tas., on P. australis (Perrin & Lucas, Jan. 1931; AD, A49632).

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

Distribution: Cockburn Sound, W. Aust., to Western Port, Vic., and the N coast of Tasmania.

Taxonomic notes: P. succulenta is a distinctive species, characterised by the dimensions, short segments, erect base to the axes, abruptly tapering and usually involute apices, the tetrasporangial branches with the tetrasporangia usually occupying less than half the width of the branch and not distorting it, and by the rather short and thick spermatangial branches. The common presence of 5 pericentral cells for 2–5 segments above the base of a branch also may be distinctive for the species. It is normally epiphytic on Posidonia australis in calm bays and inlets; in American R. inlet on Kangaroo I. it is particularly common.

The type specimen of P. spinuligera Zanardini (in Museo Civico, Venice), as judged by the description and a photograph showing a specimen epiphytic on Posidonia, is identical with P. succulenta.

P. succulenta is closely related to P. blandii Harvey; comparisons are made under the latter species.


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

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

GARNET, J.R. (1971). Checklist No. 6 – Marine and Freshwater Algae. In The Wildflowers of Wilson's Promontory National Park, pp. 93–97. (Lothian: Melbourne.)

GUILER, E.R. (1952). The marine algae of Tasmania. Checklist with localities. Pap. Proc. R. Soc. Tasmania 86, 71–106.

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

LUCAS, A.H.S. (1929a). The marine algae of Tasmania. Pap. Proc. R. Soc. Tasm. 1928, 6–27.

SEGI, T. (1966). The type or authentic specimens of Polysiphonia in Europe. Rep. Fac. Fish., Prefect. Univ. Mie 5, 503–516, Plates 1–25.

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.

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.

WOMERSLEY, H.B.S. (1956). The marine algae of Kangaroo Island 1V. The algal ecology of American River inlet. Aust. J. Mar. Freshw. Res. 7, 64–87, Plates 1–7.

WOMERSLEY, H.B.S. (1979). Southern Australian species of Polysiphonia Greville (Rhodophyta). Aust. J. Bot. 27, 459–528.

ZANARDINI, J. (1874). Phyceae Australicae novae vel minus cognitae. Flora 57, 486–490, 497–505.

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. 83 A–D.

Figure 83 image

Figure 83   enlarge

Fig. 83. A–D. Polysiphonia succulenta (AD, A32930). A. Habit. B. Cystocarps. C. Spermatangial branches. D. Tetrasporangial branches. E–H. Polysiphonia blandii (E, isotype in BM; F, G, AD, A48950; H, AD, A26342). E. Habit. F. Cystocarps. G. Spermatangial branches. H. Branches with young tetrasporangia. (All as in Womersley 1979, courtesy of Aust. J. Bot.)

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