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Service Notice

The Western Australian Herbarium’s collections management system, WAHerb, and DBCA’s flora taxonomic names application, WACensus, have been set to read-only mode since 1 October 2025. Recent taxonomic changes are not currently being reflected in Florabase, herbarium collections, or the census. Due to the rapidly approaching holiday season and associated agency and facility soft closures, along with the substantial work involved in data mapping, cleaning, and verification, the migration to the new collection management software is not expected to occur before 1 March 2026, when a further update will be provided. Please reach out to us if you have any questions or concerns.

The notice period started at 9:45 am on Friday, 12 December 2025 +08:00 and will end at 12:00 pm on Monday, 2 March 2026 +08:00.

Plocamium angustum (J.Agardh) Hook.f. & Harv.

Reference
London J.Bot. 404 (1847)
Conservation Code
Not threatened
Naturalised Status
Native to Western Australia
Name Status
Current

Scientific Description

Habit and structure. Thallus to 25cm high, with numerous, erect, slender, rather linear axes arising from the basal stolons. Axes usually 0.5–1(–1.5) mm broad, bearing ramuli in alternating pairs, the upper often developing into a lateral branch similar to the axes; lower ramuli subulate, 1–1.5(–2) mm long, less than 0.5 mm broad at their base, usually entire but in some plants with several small serrations or spines on the abaxial margin.

Reproduction. Sexual thalli dioecious. Cystocarps sessile on adaxial base of ramulus or on adjacent axis, globular, smooth to slightly verrucose, 600–900 µm across. Spermatangia covering the surface of slender ramuli, becoming tufted and basally branched, the tufts enlarging with age and in some plants stichidia usually unbranched and swollen, 60–100µm in diameter, terete and fairly straight, the stalk remaining slender; tetrasporangia 50–70 µm long and 25–30 µm in diameter, zonately divided.

Distribution. New Zealand. Cannan Reefs, Great Australian Bight, S. Aust., to Tuggerah Lakes, N.S.W. and around Tas.

Habitat. Common on coasts of rough to moderate wave action and known from shaded pools near low water level to 50 m.

[After Womersley, Mar. Benthic Fl. Southern Australia IIIA: 378–379 (1994)]

John Huisman & Cheryl Parker, 3 August 2021

Distribution

IBRA Regions
Esperance Plains, Swan Coastal Plain.
IBRA Subregions
Perth, Recherche.
IMCRA Regions
Central West Coast, Leeuwin-Naturaliste, WA South Coast.
Local Government Areas (LGAs)
Cockburn, Dandaragan, Esperance, Mandurah.