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Electronic Flora of South Australia Species Fact Sheet

Sargassum varians Sonder 1845: 51; 1848: 163; 1853: 671.

Phylum Phaeophyta – Order Fucales – Family Sargassaceae

Selected citations: J. Agardh 1872: 64; 1889: 49, p1. 16 figs 1–8. Womersley 1954b: 349, fig. 1g,h, pl. 4 fig. 2.

Thallus (Fig. 159A) medium to dark brown, 10–50 cm long, with stipes 2–10 cm long, compressed, 2–4 mm broad, with prominent, distichous, branch residues, bearing apically and distichously 2–4 primary branches. Holdfast discoid-conical, 5–15 mm across, with one (to a few) stipes; epilithic. Primary branches 5–40 cm long, below with compressed axes 3–5 (–7) mm broad, producing distichously from their margins laterals which become reflexed and twisted at their origin. Laterals (lower) at first simple, soon becoming pinnate, basally retroflex, 3–8(1 3)cm long with branches 2–6(1 0) mm broad, with rounded to acute apices; upper laterals arising irregularly radially from the subterete axes, with a sharp transition from the lower laterals, pinnate, with filiform ramuli, 0.5–2 cm long. Vesicles petiolate, subspherical, (2–) 3–6 (–10) mm in diameter, mutic or occasionally with a slender to compressed mucro to 2 cm long.

Reproduction: Thalli dioecious or monoecious. Receptacles (Fig. 160E) unisexual or bisexual, in dense clusters, petiolate, simple, each in the axil of a ramulus, ovoid to lanceolate, smooth, 1–3 mm long and 0.5–1 mm in diameter, with scattered ostioles. Conceptacles mostly unisexual, occasionally bisexual; oogonia sessile, subspherical to ovoid, 100–170 µm long and 90–120 µm in diameter, few per conceptacle; antheridia sessile or on branched paraphyses, ovoid, 14–20 µm long and 10–12 µm in diameter.

Type from W. Aust. (Preiss); in MEL, 30182.

Selected specimens: Gnarabup Beach (20 km N. of Hamelin Bay), W. Aust., reef pools (Womersley, 1.ix.1979; ADU, A50690). Eucla, W. Aust., drift (Womersley, 2.ii.1954; ADU, A19337). Egg I., Isles of St Francis, S. Aust., 32–38 m deep (Shepherd, 11.i.1971; ADU, A38032). Elliston, S. Aust., 11 m deep in bay (Shepherd, 14.v.1971; ADU, A38648). Sturt Bay, S. Aust., drift ( Womersley, 8.iv.1950; ADU, A13084). Pennington Bay, Kangaroo I., S. Aust., drift ( Womersley, 4.ix.1946; ADU, A4014). Garden Beach, Portland, Vic., drift (Beauglehole, 8.vii.1951; ADU, A21732). Boat Harbour Point, N. Tas., drift (Womersley, 16.x.1982; ADU, A55724).

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

Distribution: From Cottesloe, W. Aust., to Wilsons Prom., Vic., and the north coast of Tasmania.

Taxonomic notes: S. varians has similar basal laterals to S. sonderi, but they are basally retroflex from compressed axes, and the vesicles are distinctly larger than in the latter species.


AGARDH, J.G. (1872). Till algernes systematik. Ada Univ. lund. 9(8), 1–71.

AGARDH, J.G. (1889). Species Sargassorum Australiae. K. Svenska Vetenskapsakad. Handl. 23(3), 1–133, Plates 1–31.

SONDER, O.W. (1845). Nova Algarum genera et species, quas in itinere ad oras occidentales Novae Hollandiae, collegit L. Preiss. Bot. Ztg 3, 49–57.

SONDER, O.W. (1848). Algae. In Lehmann, C., Plantae Preissianae. Vol. 2, pp. 161–195. (Hamburg.)

SONDER, O.W. (1853). Plantae Muellerianae. Algae. Linnaea 25, 657–709.

WOMERSLEY, H.B.S. (1954b). Australian species of Sargassum, subgenus Phyllotrichia. Aust. J. Bot. 2, 337–354, Plates 1–5.

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

Illustrations in Womersley Part II, 1997: FIGS 159A, 160E.

Figure 159 image

Figure 159   enlarge

Fig. 159. A. Sargassum varians (ADU, A38648). B. Sargassum verruculosum (ADU, A26554).

Figure 160 image

Figure 160   enlarge

Fig. 160. Receptacles of species of Sargassum subgenus Phyllotrichia. A. Sargassum decurrens (ADU. A53922). B. Sargassum heteromorphum (ADU, A23954). C. Sargassum decipiens (ADU, A57476). D. Sargassum sonderi (ADU, A9314). E. Sargassum varians (ADU, A55724). F. Sargassum verruculosum (ADU. A18826).

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