Rosenvingea orientalis (J.Agardh) Børgesen
Dansk Bot.Ark. 2(2):26 (1914)

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

Distribution

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

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

IBRA Subregions: Geraldton Hills, Perth, Pindanland.

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

Local Government Areas (LGAs): Broome, Coorow, East Fremantle, Greater Geraldton, Karratha, Northampton, Rockingham.

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

Habit and structure. Thallus erect, olive-brown, soft and lax, to 15 cm tall; branching mostly subdichotomous, divaricate (almost cervicorn); interdichotomies 1.5–5.0 cm long. Axes 1–3 mm diam., tubular, with acuminate apices. Structure with the central cavity and frond wall 3–5 cell layers thick, this with an inner layer of large hyaline medullary cells c. 50 μm diam., grading to a cortex of pigmented cells. Outermost layer of the cortex with cells longitudinally aligned, somewhat irregularly shaped, 10–15 μm long and 4–7 μm wide in surface view. Hairs in small clusters on the frond surface, 4–7 μm diam. Reproductive structures not observed.

Distribution. Widespread in tropical regions of the Indo-Pacific and Atlantic Oceans. In W.A. it occurs south to Cape Peron.

Habitat. Grows on rock in the intertidal and shallow subtidal, usually associated with sand.

[After Huisman, Algae of Australia: Mar. Benthic Algae of North-western Australia, 1. Green and Brown Algae 179-180 (2015)]