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Service Notice

The Western Australian Herbarium’s collections management system and census were set to read-only mode on 1 October 2025. Taxonomic updates published since this time are not being reflected in Florabase, herbarium collections, or Western Australia’s taxonomic names census (Nomos). Conservation listings displayed on Florabase may also be out of date. Please refer to DBCA’s Threatened species and communities webpage for the most recent Threatened and Priority Flora List, noting that recent taxonomic updates are similarly not included. Our database migration is moving to a staging phase. We thank you for your patience as we ensure the integrity of our biodiversity data, develop new workflows, and train staff to use the new systems. Please reach out to us if you have any questions or concerns.

The notice period started at 12:00 pm on Wednesday, 1 October 2025 +08:00 and will end at 12:00 pm on Friday, 1 January 2027 +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.