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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 Conservation listings displayed on Florabase may also be out of date.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.

Gelidium johnstonii Setch. & N.L.Gardner

Reference
Proc.Calif.Acad.Sci. 12:742-743, Pl. 46a, 72, 73 (1924)
Conservation Code
Not threatened
Naturalised Status
Native to Western Australia
Name Status
Current

Scientific Description

Habit and structure. Thallus with limited prostrate terete axes to 0.5 mm diam., attached by peg-like laterals, bearing erect axes to 45 mm tall. Erect axes flattened, to 1.5 mm broad, 130–150 µm thick, bearing flattened lateral branches from the margins in a subopposite to alternate, distichous pattern. Structure uniaxial, with a prominent dome- or wedge-shaped apical cell; in section with a medulla of longitudinal filaments, these cross-linked by pit connections, and a cortex of 3–5 layers of smaller pigmented cells, the outermost slightly elongate. Rhizines conspicuous in the medulla/cortex interface, c. 5 µm diam. Outer cells rounded in surface view, 3–5 µm wide, in vague meandering longitudinal lines, with occasional larger cells to 7 µm wide which are slightly immersed and produce elongate hairs.

Reproduction. Spermatangia forming in irregularly shaped sori near branch apices, cut off from surface cells. Cystocarps forming subapically on primary and lateral branches, protuberant, bilocular. Tetrasporangia not observed.

Distribution. Widespread in the Pacific Ocean.

Habitat. Epilithic in the intertidal.

[After J.M. Huisman, G.H. Boo & S.M. Boo in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 248–250 (2018)]