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Electronic Flora of South Australia Species Fact Sheet

Codium dimorphum Svedelius 1900: 300.

Phylum Chlorophyta – Order Codiales – Family Codiaceae

Selected citations: Silva & Womersley 1956: 262, fig. 1.

Thallus (Fig. 75A) medium to dark green, smooth and firm, applanate and strongly adherent, rounded with marginal lobes, 2.5–6 (–10) mm thick, to 10 cm across. Utricles (Fig. 76A) in small to large clusters, (45–) 55–80 (–100) µm in diameter, 0.5–1 (–1.5) mm long, usually slightly constricted just below apices then slightly broader below, apices rounded to subtruncate with slightly thickened wall (4–7 µm thick), often more so peripherally; utricles from thallus margin often broader (to 125 µm in diameter) below their apices, which are thidcened (to 30 µm); hairs absent. Medullary filaments extending from the evenly tapering lower part of utricles, wall undulate, (15–) 20–35 µm in diameter, without plugs. Gametangia narrowly ellipsoid to cylindrical, 44–75 µm in diameter, 240–380 µm long.

Type from Guaitecas I., Chile; in Herb. Svedelius, UPS.

Selected specimens: Cape Forestier, Tas., lower eulittoral (Bennett, 21.vi.1954; ADU, A19830). Wineglass Bay, Freycinet Pen., Tas., low eulittoral (Edyvane, 26.iii.1982; ADU, A53000). Bicheno, Tas., upper sublittoral amongst Durvillaea (Womersley, 3.xi.1982; ADU, A54027).

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

Distribution: Chile, Chatham I., New Zealand (South I., Stewart I.).

In southern Australia, known only from south-east Tasmania. This is probably a sub-antarctic species which just reaches Tasmania. It occurs in the lowest eulittoral or uppermost sublittoral among the stipes of Durvillea, forming thin, rounded, tightly adherent patches on the rock.


SILVA, P.C. & WOMERSLEY, H.B.S. (1956). The genus Codium (Chlorophyta) in southern Australia. Aust. J. Bot. 4, 261–289.

SVEDELIUS, N. (1900). Algen aus den Landern der Magellansstrasse and West Patagonien. Svenska Exp. till Magellansländerna, 3(8), 283–316, Plates 16–18.

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

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (31 May, 1984)
The Marine Benthic Flora of Southern Australia
Part I
©Board of the Botanic Gardens and State Herbarium, Government of South Australia

Illustrations in Womersley Part I, 1984: FIGS 75A, 76A.

Figure 75 image

Figure 75   enlarge

Fig. 75. A. Codium dimorphum (ADU, A19830). B. Codium capitulalum (ADU, A19384). C. Codium lucasii (ADU, A45051). D. Codium perriniae (ADU, A37803). E. Codium spongiosum (ADU, A1581).

Figure 76 image

Figure 76   enlarge

Fig. 76. Utricle clusters with gametangia. A. Codium dimorphum (ADU, A19830). R. Codium capitulatum (ADU, A13623). C. Codium lucasii (ADU, A20401). D. Codium lucasii (Royce 1039 in PERTH, UC). E. Codium perriniae (ADU, Al2781). F. Codium spongiosum (ADU, A19383). (After Silva & Womersley 1956.)

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