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Cystophora retorta (Mertens) J. Agardh 1848: 243; 1896: 49.

Phylum Phaeophyta – Order Fucales – Family Cystoseiraceae

Selected citations: Nizamuddin 1964c: 42–63. Womersley 1964: 92, figs 34,35, pl. 11.


Fucus retortus Mertens 1819: 185.

Thallus (Fig. 144A) medium brown, 20–80 (–120) cm long, openly branched in one plane. Holdfast discoid-conical, 0.5–1.5 cm across, with a single, terete, stipe; epilithic. Primary axes strongly compressed (W/T 2–3), relatively straight, 2–5 (–7) mm broad and 1–2 mm thick, alternately distichously branched from the face; secondary axes (2–) 4–12 cm long (occasionally developing as main axes), 0.5–3 cm apart, usually not retroflex, leaving slight, stubby, residues, sometimes scalariform on secondary axes. Laterals (Fig. 145F) 3–7 cm long, 1–5 (–10) mm apart on axes, branched in one plane with ramuli alternate but soon becoming subdichotomous with broadly rounded axils; ultimate ramuli 1–5 cm long, 0.5–1 mm in diameter, terete or slightly compressed. Vesicles usually absent or rare, occasionally plentiful, replacing basal ramulus of a lateral, ovoid to ellipsoid and often asymmetric, petiolate, 5–14 mm long and 2–5 (–9) in diameter, mutic (or apiculate when young).

Reproduction: Thalli monoecious. Receptacles (Fig. 145G) mostly simple, (1–) 2–5 (–8) cm long and 1–2 mm thick, terete to slightly compressed, undulate to slightly torulose. Conceptacles normally bisexual, often separated by sterile tissue, with ostioles more or less in two rows, with simple paraphyses; oogonia sessile, ovoid, 80–110 µm long and 60–90 µm in diameter; antheridia sessile or on branched paraphyses, elongate-ovoid, 16–24 µm long and 8–12 µm in diameter.

Type from "Novae Hollandiae"; in PC.

Selected specimens: Nickol Bay, W. Aust. (1880; Herb. Sonder, MEL, 461). Gnarabup Beach, 20 km N. of Hamelin Bay, W. Aust., in reef pools (Womersley, 1.ix.1979; ADU, A50688). Point Valliant, Two People Bay, W. Aust., 1–4 m deep (Clarke & Engler, 30.viii.1979; ADU, A50965). Smooth I., Isles of St Francis, S. Aust., 21 m deep (Shepherd, 29.iii.1980; ADU, A52168). Sceale Bay, S. Aust., upper sublittoral (Womersley, 11.ii.1954; ADU, A19469). Aldinga, S. Aust., upper sublittoral pools (Womersley, 3.xi.1963; ADU, A26877). Victor Harbor, S. Aust., drift ( Womersley, 23.v.1953; ADU, A18756). Pennington Bay, Kangaroo I., S. Aust., drift ( Womersley, 25.v.1945; ADU, A2377). Point Bunbury, Apollo Bay, Vic., lower eulittoral pools (Womersley, 19.v.1980; ADU, A51071). Sorrento, Vic., upper sublittoral pools (Womersley, 2.vi.1953; ADU, A18818). Walkerville, Vic., in pools (Sinkora A1490, 21.ii.1972; ADU, A42278). Wilsons Prom., Vic. (Mueller, June 1853; MEL, 467, 468). Remine, Tas., reef pools (Wollaston & Mitchell, 25.ii.1964; ADU, A27493). Shelter Point, Boat Harbour Beach, N. Tas., lower eulittoral pools (Womersley, 16.x.1982; ADU, A55726). Swansea, Tas., drift (Womersley, 19.i.1949; ADU, A10224). Taroona, Hobart, Tas., upper sublittoral ( Womersley, 13.i.1949; ADU, A10125).

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

Distribution: From Nickol Bay, W. Aust. to Wilsons Promontory, Vic., and around Tasmania.

Taxonomic notes: C. retorta is often a common species in larger pools and the upper sublittoral (to 21 m deep) with moderate water movement. It is closely related to C. siliquosa, differing in the compressed rather than quadrangular axis, the occasional presence of vesicles, and in having bisexual conceptacles.


AGARDH, J.G. (1848). Species, Genera et Ordines Algarum. Vol. 1. (Gleerup: Lund.)

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

MERTENS, M. (1819). Sur plusieurs espêces de Fucus, nouvelles ou peu connues, observées dans la collection du Muséum. Mem. Mus. Natl Hist. Nat., Paris 5, 172–90, Plates 13–15.

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: FIGS 144A, 145F,G.

Figure 144 image

Figure 144   enlarge

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

Figure 145 image

Figure 145   enlarge

Fig. 145. Receptacles of species of Cystophora. A. Cystophora brownii (ADU, A26713). B,C. Cystophora gracilis (ADU, A26725, holotype). D. Cystophora harveyi (ADU, A50628, holotype). E. Cystophora tenuis (ADU, A50627, holotype). F,G. Cystophora retorta (ADU, A26877). F. Secondary and tertiary axes and laterals. G. Receptacles. H. Cystophora siliquosa (ADU, A2812).

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