Acanthophora dendroides Harv.
Trans.Roy.Irish Acad. 538 (1855)

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

Distribution

Beard’s Provinces: South-West Province.

IBRA Regions: Swan Coastal Plain.

IBRA Subregions: Perth.

IMCRA Regions: Abrolhos Islands, Central West Coast, Kimberley, Leeuwin-Naturaliste, Pilbara (nearshore), Shark Bay, WA South Coast.

Local Government Areas (LGAs): Broome, Cockburn, Coorow, Dandaragan, Esperance, Greater Geraldton, Irwin, Karratha, Mandurah, Rockingham, Shark Bay.

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

Habit and structure. Thallus dark brown-red, 5–12 cm high, much branched irregularly radially for 3–4 orders, branches terete, main axes 1–1.5 mm in diameter, lesser branches 400–600 µm in diameter, all branches bearing short spines irregularly spirally. Holdfast discoid, with spreading stolons; probably epilithic. Structure. Apices of branches rounded and depressed, with trichoblasts within the depressions. Pericentral cells 5, remaining clear in older branches and becoming thick-walled, with a compact cortex grading to an outer layer of longitudinally elongate cells; small cells and rhizoids developing around the axial cells and pericentral (and inner cortical) cells. Spines multicellular, 200–400 µm long, bases 100–300 µm broad.

Reproduction. Gametophyte plants not described from Australia. Cystocarps globose and sessile, spermatangial plates discoid, margins with large oblong cells. Tetrasporangial stichidia formed from smaller lateral branches, 1–2 mm long and 300–500 µm in diameter, usually bearing spines; tetrasporangia cut off from pericentral cells, several per whorl, (50–)80–110 µm in diameter.

Distribution. W. Aust., N.S.W. and Qld; in southern Australia, only known from Denial Bay, S. Aust. Widespread around the Indian Ocean.

[After Womersley, Mar. Benthic Fl. Southern Australia IIID: 409 (2003)]