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Electronic Flora of South Australia Species Fact Sheet

Polysiphonia infestans Harvey 1855b: 539; 1863, synop.: xx.

Phylum Rhodophyta – Family Rhodomelaceae – Tribe Polysiphonieae

Selected citations: J. Agardh 1863: 959. Beanland & Woelkerling 1982: 98. Cribb 1983: 131, pl. 69 figs, 1, 2. De Toni 1903: 891. Huisman 2000: 177. Huisman & Walker 1990: 439. Huisman et al. 1990: 98. Kendrick et al. 1990: 52. Kützing 1864: 14, pl. 40e-g. Lewis 1983: 262; 1984: 64. Lucas 1909: 41. Lucas & Perrin 1947: 268. Millar & Kraft 1993: 58. Silva et al. 1996: 542. Sonder 1880: 34. Womersley 1979: 481, fig. 6A–E.


Polysiphonia abscissa sensu Womersley 1947: 245; 1948: 150, 152, 156; 1950: 184; 1956: 83. [NON P. abscissa Hooker & Harvey 1845a: 266.]

Polysiphonia zostericola Lucas 1919: 177. De Toni 1924: 395. Lucas & Perrin 1947: 271.

Thallus (Fig. 82A, B) dark red-brown, 2–6 (–10) cm high with a single erect, basal axis or with several clustered axes, occasionally with slight prostrate basal parts; axes percurrent, much branched and often fastigiate above when fertile, with patent and irregular (often short) laterals in central and lower parts of thallus, often denuded below. Attachment by rhizoids from base of clumped axes; epilithic or commonly epiphytic on other algae or seagrasses. Structure. Basal axes (180–) 250–300 (–700) µm in diameter with segments L/D 0.5–1 (–1.5), attached by unicellular rhizoids cut off from the lower pericentral cells; mid parts of axes (150–) 200–400 µm in diameter with segments L/D 1–2 (–8), decreasing to 50–80 µm and segments L/D (0.5–) 0.7–1.5 (–2) in lesser branchlets which, as lower laterals, are often markedly slenderer and usually with shorter segments than the parent branch; apices straight, trichoblasts usually prominent; lateral branches replacing trichoblasts, with frequent cicatrigenous branches. Pericentral cells 4, elongate throughout the mature thallus, ecorticate throughout (in old axes in some plants, a very few corticating cells are cut off on segments close to the base), with the filaments often slightly contracted between the ends of each segment; outer wall of older branches thick, often with numerous adherent diatoms and other minute epiphytes; trichoblasts, scar cells or branches present on every segment, with a divergence of 1/4, trichoblasts moderately robust, basal cells 15–25 µm in diameter. Rhodoplasts discoid, dense and irregularly scattered.

Reproduction: Gametophytes dioecious. Carposporophytes with a small basal fusion cell and short, branched, gonimoblast bearing clavate terminal carposporangia 20–40 µm in diameter. Cystocarps (Fig. 82C) stalked, ovoid (sometimes distinctly basally broader), not or only slightly urceolate, 150–300 (–400) µm in diameter; pericarp ostiolate, 2 cells thick, outer cells isodiametric, angular. Spermatangial branches (Fig. 82D) developing as one basal branch of a trichoblast, cylindrical, 100–220 (–300) µm long and 35–90 µm in diameter, usually with a subspherical, sterile apical cell.

Tetrasporangia (Fig. 82E) forming a spiral series in upper branchlets 60–130 µm in diameter, usually distorting the branchlet, subspherical to ovoid and 45–80 µm in diameter.

Type from Princess Royal Harbour, King George Sound, W. Aust. (Harvey), on Polyphysa peniculus; holotype in Herb. Harvey, TCD (Trav. Set 22), probable isotypes (Alg. Aust. Exsicc. 180B) in BM, MEL, 1006715, and AD, Al 8284.

Selected specimens: Nanarup, W. Aust. on Laurencia, upper sublittoral (Gordon, 19.xi.1968; AD, A33996). Princess Royal Harbour, Albany, W. Aust., uppermost sublittoral (Womersley, 21.viii.1979; AD, A51385-"Marine Algae of southern Australia" No. 21 1 b.) West Beach, Esperance, W. Aust., low eulittoral (Wollaston, 21.ii.1957; AD, A32557). Greenly Beach (60 km N of Coffin Bay), S. Aust., in mid eulittoral pools (Parsons, 15.v.1968; AD, A32559). Flour Cask Bay, Kangaroo I., S. Aust., rear reef pools (Womersley, 23.xii.1968; AD, A32917). Pennington Bay, Kangaroo I., S. Aust., in upper eulittoral pool (Womersley, 21.xi.1968; AD, A32905). Robe, S. Aust., on Codium fragile, low eulittoral near slipway (Womersley, 13.ii.1978; AD, A49147-"Marine Algae of southern Australia" No. 211a). Point Lonsdale, Vic., low eulittoral (Womersley, 12.x.1982; AD, A55353-"Marine Algae of southern Australia" No. 211c). Crawfish Rock, Westernport Bay, Vic., uppermost sublittoral (Womersley, 29.viii.1971; AD, A39445). Walkerville, Vic., drift (Sinkora A2397, 27.ii.1978; AD, A53587). Low Head, Tas. (Perrin, 27.viii.1948; AD, A49569). Green Point, Marrawah, NW Tas., lower eulittoral (Womersley, 17.x.1982; AD, A55562). Arch Rock, E of Ninepin Point, Tas., 1–10 m deep (Andrews, 21.x.1994; AD, A63907). Isthmus Bay, Bruny I., Tas., lower eulittoral (Womersley, 12.x.1986; AD, A57765).

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

Distribution: Shark Bay, W. Aust., to Walkerville, Vic. and N and E Tasmania. Also known from N.S.W. (Millar & Kraft 1993, p. 58) and Queensland (Cribb 1983, p. 131).

Taxonomic notes: P. infestans is common in intertidal rock pools or where just covered at low tide on rock platforms on rough-water coasts, extending less frequently to coasts of moderate water movement. It grows on both rock and on a variety of other larger algae such as Laurencia.

Harvey's type specimens were recorded as growing on Acetabularia (Polyphysa) peniculus in Princess Royal Harbour (Albany) in King George Sound; however, no specimen of Harvey's has been seen attached to Polyphysa. The habitat is more sheltered than is typical for the species, but the type material agrees well as far as can be ascertained with the above concept of the species; however the nature of the branching in replacing trichoblasts has not been observed clearly in the type material.

P. infestans is characterised by its habit, with erect axes and patent branching with many laterals (usually cicatrigenous) much slenderer than the parent branch, the short segments (L/D rarely greater than 1.5), by the dimensions, by the branches replacing the trichoblasts, and by the irregularly swollen and distorted tetrasporangial branchlets. Slight basal cortication occurs in some larger, presumably older, plants (e.g. AD, A49147).

Some specimens from Victoria (AD, A39445) and Tasmania (AD, A49569) are larger, relatively slender below, and with considerably longer mid to lower segments (L/D 4–8) than in most forms. Such plants are often growing under considerable currents rather than strong wave action. Otherwise they are identical with the more usual forms of P. infestans, and it seems best to place them within this species. It is clear, however, that there is considerable variation in the above features in P. infestans as recognised here.

P. zostericola Lucas was described from Botany Bay, N.S.W. (type in Herb. Lucas, NSW; isotype AD, A12234), forming a dense fringe on the leaves of Zostera. A recent collection from Nowra Point, Botany Bay, low eulittoral on Zostera capricorni (Womersley, 20.v.1978; AD, A49353), of plants smaller but otherwise the same as the type collection, agrees well with the above features of P. infestans.

P. infestans is somewhat similar to P. mollis in dimensions, but differs in habit in having numerous patent, slender branches (which are generally lacking in P. mollis), in the origin of branches, in having generally shorter segments which are often medially constricted, and in the more distorted tetrasporangial branchlets. Whereas P. mollis appears to be a plant of sheltered waters (though often subject to a current) and epiphytic on Posidonia and occasionally on other algae, P. infestans occurs in moderate water movement and in pools, either epilithic or epiphytic on various other algae but usually not seagrasses.

P. infestans is doubtfully recorded from New Zealand by Laing (1927, p. 167) and Naylor (1954, p. 661); this requires confirmation.


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

BEANLAND, W.R. & WOELKERLING, W.J. (1982). Studies on Australian mangrove algae: IT. Composition and geographical distribution of communities in Spencer Gulf, South Australia. Proc. R. Soc. Vict. 94, 89–106.

CRIBB, A.B. (1983). Marine algae of the southern Great Barrier Reef—Part I. Rhodophyta. (Aust. Coral Reef Soc., Handbook 2: Brisbane.)

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

DE TONI, G.B. (1924). Sylloge Algarum omnium hucusque Cognitarum. Vol. 6. Florideae. (Padua.)

HARVEY, W.H. (1855b). Algae. In Hooker, J.D., The Botany of the Antarctic Voyage. II. Flora Novae-Zelandiae. Part II, pp. 211–266, Plates 107–121. (Reeve: London.)

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

HOOKER, J.D. & HARVEY, W.H. (1845a). Algae Antarcticae. Lund. J. But. 4, 249–276.

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. (2000). Marine Plants of Australia. (Univ. W. Aust. Press, Nedlands, W. Aust. & ABRS, Canberra, A.C.T.)

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.

KÜTZING, F.T. (1864). Tabulae Phycologicae. Vol. 14. (Nordhausen.)

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

LAING, R.M. (1927). A reference list of New Zealand marine algae. Trans. Proc. N.Z. Inst. 57, 126–185.

LEWIS, J.A. (1983). Floristic composition and periodicity of subtidal algae on an artifical structure in Port Phillip Bay (Victoria, Australia). Aquatic Bot. 15, 257–274.

LEWIS, J.A. (1984). Checklist and bibliography of benthic marine macroalgae recorded from northern Australia. I. Rhodophyta. Dept. Defence, Materials Res. Lab., Melbourne, Vic. Report MRL-R-912.

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. (1919).—Notes on Australian marine algae. II. Descriptions of four new species. Proc. Linn. Soc. N.S.W. 44, 174–179, Plate 6.

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.

NAYLOR, M. (1954). A checklist of the marine algae of the Dunedin district. Trans. Roy. Soc. N.Z. 82(3), 645–663.

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.)

WOMERSLEY, H.B.S. (1947). The marine algae of Kangaroo Island. I. A general account of the algal ecology. Trans. R. Soc. S. Aust. 71, 228–252.

WOMERSLEY, H.B.S. (1948). The marine algae of Kangaroo Island. II. The Pennington Bay Region. Trans. R. Soc. S. Aust. 72, 143–166, Plates 10–15.

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.

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. 82 A–E.

Figure 82 image

Figure 82   enlarge

Fig. 82. A–E. Polysiphonia infestans (A, AD, A18284; B, AD, 32917; C, AD, A49147; D, E, AD, A32905). A. Habit of isotype. B. Habit. C. Branches with cystocarps. D. Spermatangial branches. E. Tetrasporangial branches. F–H. Polysiphonia propagulifera (F, G, AD, A33804; H, AD, A38222). F. habit. G. Branches with propagules. H. Tendril. (All as in Womersley 1979, courtesy of Aust. J. Bot.)

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