Codium mamillosum Harv.
Trans.Roy.Irish Acad. 565 (1855)

Conservation Code: Not threatened
Naturalised Status: Native to Western Australia
Name Status: Current


Beard’s Provinces: Eremaean Province, South-West Province.

IBRA Regions: Geraldton Sandplains, Hampton, Swan Coastal Plain.

IBRA Subregions: Geraldton Hills, Hampton, Perth.

IMCRA Regions: Central West Coast, Leeuwin-Naturaliste.

Local Government Areas (LGAs): Busselton, Chapman Valley, Dandaragan, Dundas, Irwin.

Scientific Description
John Huisman & Cheryl Parker, Thursday 8 September 2016

Habit and structure. Thallus medium green, more-or-less globose, to 8 cm in diameter, attached by a tuft of rhizoids, firm when living but becoming soft. Utricles in small clusters, elongate-clavate, (400–)450–1000 µm in diameter at the apices and often expanded shortly below (to 1500 µm) then tapering to the base, (3–)4–7(–9) mm long; utricle apex rounded to subtruncate, wall slightly to moderately thickened (to 40 µm) and becoming finely lamellate; hairs absent. Medullary filaments 40–100 µm in diameter, with several from the much broader utricle base, often branched or constricted near their origin.

Reproduction. Gametangia narrowly ellipsoid to ovoid, often tapering above, 130–250 µm in diameter, (350–)500–800 µm long, 1–3 per utricle, 1–2 mm below apices.

Distribution. From Dongara, W. Aust., to Warrnambool, Vic. Hawaiian I., Japan.

Habitat. Occurs at low tide level in shaded situations under moderate wave action, but is essentially a sublittoral species extending down to 42 m.

[After Womersley, Mar. Benthic Fl. Southern Australia I: 230 (1984)]