Sebdenia flabellata (J.Agardh) P.G.Parkinson
Halymenia 12 (1980)

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


Beard’s Provinces: Northern Province.

IBRA Regions: Dampierland.

IBRA Subregions: Pindanland.

IMCRA Regions: Abrolhos Islands, Canning, Central West Coast, Kimberley, Leeuwin-Naturaliste, Pilbara (nearshore), Pilbara (offshore).

Local Government Areas (LGAs): Ashburton, Broome, Cockburn, Derby-West Kimberley, Greater Geraldton, Karratha, Port Hedland, Wyndham-East Kimberley.

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

Habit and structure. Thallus erect, pale pink, flabellate, to 8–14 cm tall, arising from a discoid holdfast, dichotomously branched with rounded axils; axes terete to slightly flattened, mostly soft but turgid, near base 2–4 mm in diameter and in some specimens cartilaginous, broadening to 8–12 mm wide, broadest just below dichotomies. Structure multiaxial, with a filamentous medulla of elongate cylindrical cells 15–20 µm in diameter, L/B c. 10, grading to an outer medulla of stellate cells 3–4 layers of large hyaline cells, then a small-celled cortex, the surface cells subspherical, 10–20 µm in diameter. Spherical to obovoid gland cells 25–35 µm in diameter borne laterally on medullary filaments.


Reproduction. Reproductive structures not observed.


Distribution. Widely distributed in tropical and warmer seas. In W. Aust., known from Rottnest I. north to the Maret Is.; it probably occurs throughout tropical Australia.


Habitat. Epilithic, often on rocks in sandy regions of the subtidal.