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Electronic Flora of South Australia Species Fact Sheet

Cystophora siliquosa J. Agardh 1871: 445; 1896: 49.

Phylum Phaeophyta – Order Fucales – Family Cystoseiraceae

Selected citations: Nizamuddin 1964c: 42–63. Womersley 1964: 93, fig. 36, pl. 12 fig. 1.

Thallus (Pl. 8 fig 3; Fig. 144B) medium to dark brown, 40–100 cm (-2.5 m) long, fairly openly branched in one plane. Holdfast discoid-conical, 0.5–1.5 cm across, with a single stipe; epilithic. Primary axes relatively straight, quadrangular to almost square in transverse section (W/T 1–1.5) with rounded corners, tapering gradually above, 2–5 mm broad and thick, alternately distichously branched from the face; secondary axes not or only slightly retroflex, 5–10 cm long and 1–2 (–3) cm apart, sometimes developing into long main axes; lower secondary axes and laterals usually lost, with short, stumpy, residues 1–4 mm apart and 0.5–1.5 mm long. Laterals (2–) 3–5 (–8) cm long, usually alternately distichous, becoming subdichotomous, with rounded axils; ramuli linear, terete to slightly compressed, 0.5–3 cm long, 0.3–0.8 mm in diameter. Vesicles absent.

Reproduction: Thalli dioecious. Receptacles (Fig. 145H) mostly simple, straight to undulate, 3–8 cm long and 1–2 mm broad, slightly to distinctly compressed, attenuate at both ends. Conceptacles with ostioles in two rows on the margins, slightly swollen and separated by sterile tissue, unisexual; oogonia sessile, ovoid, 100–140 µm long and 70–100 µm in diameter, with simple paraphyses; antheridia on branched paraphyses, ovoid, 25–30 µm long and 10–12 pm in diameter.

Type from Port Phillip, Vic. (Mueller); in Herb. Agardh, LD, 1194.

Selected specimens: Geographe Bay, W. Aust. (Herb. Agardh, LD). West Beach, Esperance, W. Aust., on reef (Burbidge, 7.i.1935; ADU, A46617). Elliston, S. Aust., 3–5 m deep in southern bay (Shepherd, 19.iv.1970; ADU, A35848). Cape Carnot, S. Aust., upper sublittoral pools (Womersley, 8.i.1951; ADU, A13816). Point Avoid, S. Aust., upper sublittoral pools (Womersley, 10.i.1987; ADU, A57372). Pondalowie Bay, Yorke Pen., S. Aust., 5–8 m deep (Shepherd, 14.iv.1963; ADU, A26613). Pennington Bay, Kangaroo I., S. Aust., in reef pools (Womersley, 28.i.1946; ADU, A2812). Robe, S. Aust., upper sublittoral pools near jetty (Womersley, 16.xii.1986; ADU, A57316-"Marine Algae of southern Australia" No. 276). Bridgewater Bay, Vic., eulittoral pool (Beauglehole, 29.v.1949; ADU, A11987). Point Roadknight, Vic., drift (Womersley, 6.vi.1953; ADU, A18791). Observation Point, Port Phillip, Vic., 4–5 m deep (Macpherson, 18.i.1959; ADU, A23214). Flinders, Vic., upper sublittoral (Womersley, 18.i.1967; ADU, A31784). Walkerville, Vic., upper sublittoral (Bennett, Nov. 1949; ADU, A15248). Sealers Cove, Wilsons Prom., Vic. (MEL, 495). George Town, Tas. (Gunn; Herb. Agardh, LD).

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

Distribution: From Geographe Bay, W. Aust. to Wilsons Prom., Vic., and the N. coast of Tasmania.

Taxonomic notes: C. siliquosa is common in pools and the upper sublittoral on rough-water coasts of South Australia and Victoria. It is closely related to C. retorta, differing in its thick, quadrangular axes and in being dioecious.


AGARDH, J.G. (1871). Om Chatham-Oarnes Alger. K. Vetensk Akad. Forschandl. 5, 435–456.

AGARDH, J.G. (1896). Analecta Algologica. Cont. III. Ada Univ. lund. 32, 1–140, Plate 1.

NIZAMUDDIN, M. (1964c). The anatomy and life history of Cystophora, Acrocarpia and Caulocystis (Fucales). Bot. Mar. 7, 42–63.

WOMERSLEY, H.B.S. (1964). The morphology and taxonomy of Cystophora and related genera (Phaeophyta). Aust. J. Bot. 12, 53–110, Plates 1–16.

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: PLATE 8 fig 3; FIGS 144B, 14511.

Plate 8 image

Plate 8   enlarge

PLATE 8 fig. 1. Caulocystis cephalornithos. A rock pool plant photographed on rock, Robe, S. Aust.
fig. 2. Cystophora platylobium 18 m deep off Althorpe I., S. Aust. (ADU, A57434) (Photo: M. Retallick).
fig. 3. Cystophora siliquosa at Point Avoid, S. Aust. (ADU, A57372).
fig. 4. Sargassum fallax. An upper sublittoral plant photographed on rock, Robe, S. Aust.

Figure 144 image

Figure 144   enlarge

Fig. 144. A. Cystophora retorta (ADU, A18818). B. Cystophora siliquosa (ADU, A2812).

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