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Electronic Flora of South Australia Species Fact Sheet

Seirococcus axillaris (R. Brown ex Turner) Greville 1830: synop. xxxiv.

Phylum Phaeophyta – Order Fucales – Family Seirococcaceae

Selected citations: Harvey 1858: p1. 4. Lucas 1936: 68, fig. 41. Nizamuddin 1962a: 195, figs 2,6; 1968a: 88, figs 33–40, pl. III. Womersley 1967: 253.


Fucus axillaris R. Brown ex Turner 1811: 28, pl. 146.

Thallus (Fig. 125B) medium to dark brown, 0.5–2 m long, much branched irregularly laterally and essentially complanately, with long axes or primary branches bearing marginally alternate, distichous, laterals, some developing into long branches, stipe 1–10 cm long, subterete, 3–8 mm in diameter. Holdfast 1–4 cm across, developing a circular raised rim which bears closely adjacent, simple or branched, haptera 1–2 cm long; epilithic. Axes or primary branches straight to slightly flexuous, 3–5 (–8) mm broad, (1–) 2–5 mm thick, bearing alternate, simple, laterals at intervals of (0.5–) 1–2 cm. Laterals linear to slightly curved, tapering above, not or slightly basally constricted, 5–10 (–15) cm long and 4–12 mm broad. Growth from 1–3 four-sided apical cells in an apical depression. Structure with a medulla of elongate cells and hyphae, and a cortex of isodiametric cells with a surface meristoderm increasing the cortex; outer cells densely phaeoplastic.

Reproduction: Thalli monoecious. Receptacles (Fig. 125C) clustered along the adaxial edges of laterals, becoming dense and radiating to the sides of the lateral edges, spreading to the edge of the parent branch, clusters 1–3 (–6) cm long, individual receptacles terete, verrucose, 2–5 (–8) mm long and 0.5–1 mm in diameter. Conceptacles (Fig. 127H) unisexual, with simple or occasionally branched paraphyses in the female conceptacles; oogonia (Fig. 127H) sessile, ovoid, with an apical mesochiton collar and a single egg, 120–270 µ long and 60–150 µm in diameter; antheridia (Fig. 127H) on branched paraphyses, elongate-ovoid, 20–40 µm long and 8–14 in diameter.

Type from Port Dalrymple (Tamar Est. mouth), Tas.; in BM (ex K).

Selected specimens: Fishery Bay, S.W. of Port Lincoln, S. Aust., drift ( Womersley, 21.ii.1959; ADU, A22482). Memory Cove, S. of Port Lincoln, S. Aust., 40 m deep (Baldock, 2.i.1964; ADU, A17149). Pennington Bay, Kangaroo I., S. Aust., drift (Womersley, 4.i.1948; ADU, A6548). Dubious Rock, West I., S. Aust., 21 m deep (Shepherd, 3.i.1966; ADU, A30290). Yilki, Victor Harbor, S. Aust., drift ( Womersley, 3.xii.1986; ADU, A57285). Robe, S. Aust., drift ( Womersley, 23.ix.1986; ADU, A57202-"Marine Algae of southern Australia" No. 272).

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

Distribution: From Fishery Bay (S.W. of Port Lincoln), S. Aust., to Walkerville, Vic., and around Tasmania, from 3 to 40 m deep.

Taxonomic notes: Seirococcus is distinctive in the terete, marginal and axillary, densely clustered receptacles. It occurs mainly in deep water (3–40 m).


GREVILLE, R.K. (1830). Algae Britannicae. (Edinburgh.)

HARVEY, W.H. (1858). Phycologia Australica. Vol. I, Plates 1–60. (Reeve: London.)

LUCAS, A.H.S. (1936). The Seaweeds of South Australia. Part 1. Introduction and the Green and Brown Seaweeds. (Govt Printer: Adelaide.)

NIZAMUDDIN, M. (1962a). Classification and the distribution of the Fucales. Bot. Mar. 4, 191–203.

NIZAMUDDIN, M. (1968a). Morphology and anatomy of Phyllospora, Scytothalia and Seirococcus (Fucales). Bot. Mar. 11, 81–105.

TURNER, D. (1811). Fuci sive Plantarum Fucorum Generi a Botanicis Ascriptarum 'cones Descriptiones et Historia. Vol. 3, pp. 1–148, Plates 135–196. (London.)

WOMERSLEY, H.B.S. (1967). A critical survey of the marine algae of southern Australia. II. Phaeophyta. Aust. J. Bot. 15, 189–270.

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

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
Part II
©Board of the Botanic Gardens and State Herbarium, Government of South Australia

Illustration in Womersley Part II, 1997: FIGS 125B,C, 12711.

Figure 125 image

Figure 125   enlarge

Fig. 125. A. Phyllospora comosa (ADU, A57324). B,C. Seirococcus axillaris (B, ADU, A57202; C, ADU, A57285). B. Habit. C. Branches with adaxial receptacles.

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