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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.

Herposiphonia mermaidensis Huisman

Reference
Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae 514-515, Fig. 149A-E (2018)
Conservation Code
Not threatened
Naturalised Status
Native to Western Australia
Name Status
Current

Scientific Description

Habit and structure. Thallus with prostrate axes bearing lateral indeterminate and dorsal determinate branches alternately, the successive indeterminate branches on alternate sides. Prostrate axes 70–90 µm diam., with 9 pericentral cells [mature segment L:B 2–2.6], attached to the substratum by elongate unicellular rhizoids arising from the ventral surface, distal on each segment. Determinate branches arising from the same dorsal position (i.e. not deflected from side to side), more than 7 mm and 40 segments long; basal segment short, with 4 pericentral cells, suprabasal segment with 7 or 8 pericentral cells, then more distal segments with 11–16 pericentral cells. Developing determinate branches strongly curved, 55–75 µm diam. [segment L:B to 1], initially lacking trichoblasts but these arising later on up to 10 apical segments in a spiral pattern. Mature branches 70–85 µm diam. [segment L:B 2–2.5]. Trichoblasts initially secund, becoming subdichotomous, to 1.2 mm long at maturity.

Distribution. Known only from Mermaid Reef, Rowley Shoals, Western Australia.

Habitat. epiphytic on Pterocladiella caerulescens in the subtidal.

[After J.M. Huisman in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 514–515 (2018)]