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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.

Caulacanthus ustulatus (Turner) Kütz.

Reference
Phycol.General. 395 (1843)
Conservation Code
Not threatened
Naturalised Status
Native to Western Australia
Name Status
Current

Scientific Description

Habit and structure. Thallus forming a tangled mat of decumbent axes attached to the substratum by clusters of multicellular rhizoids arising from outer cortical cells, with irregularly produced upright axes to 1.5–2.5 mm tall bearing sparse short lateral branches. Axes terete to slightly flattened, 100–350 µm in diameter, tapering to 60 µm in diameter just below the distinctly pointed apices. Central axis conspicuous, with cells 35–100 µm long and 12–20 µm in diameter when mature, each bearing a pair of di-trichotomously branching lateral filaments that traverse a small cavity before forming a pseudoparenchymatous cortex of 2–3 layers. Outer cortical cells angular in surface view, 5–12 µm broad.

Reproduction. Reproductive structures not seen.

Distribution. Widespread species along tropical and warm-temperate coasts. It has been recorded from most regions, with the exception of the western Atlantic and Central and South America.

Habitat. C. ustulatus grows on intertidal rock or is epiphytic on a variety of algae and mangroves.