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Service Notice

The Western Australian Herbarium’s collections management system, WAHerb, and DBCA’s taxonomic names application, WACensus, have been set to read-only mode since 1 October 2025. Recent taxonomic changes are not reflected in Florabase, herbarium collections, or in the census. We are hoping to be able to reinstate services around December 15; we will provide an update at that time.

The notice period started at 9:00 am on Wednesday, 1 October 2025 +08:00 and will end at 12:00 pm on Monday, 15 December 2025 +08:00.

Sebdenia polydactyla (Børgesen) M.P.Balakr.

Reference
Proc.Symp.Algol.New Delhi 1959:89 (1961)
Conservation Code
Not threatened
Naturalised Status
Native to Western Australia
Name Status
Current

Scientific Description

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, 2–4 mm diam. near the base 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 diam. [L:B c. 10], grading to an outer medulla of stellate cells, 3 or 4 layers of large hyaline cells, then a small-celled cortex, the surface cells subspherical and 5–10 µm diam. Spherical to obovoid vesicular cells 25–35 µm diam., borne laterally on medullary filaments.

Reproduction. Reproductive structures not seen.

Distribution. Widely distributed in tropical and warm-temperate regions of the Indian Ocean.

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

[After J.M. Huisman & G.W. Saunders in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 302–303 (2018)]

John Huisman & Olga Nazarova, 3 August 2021

Distribution

IBRA Regions
Dampierland, Geraldton Sandplains, Pilbara.
IBRA Subregions
Geraldton Hills, Pindanland, Roebourne.
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.