Skip to main content

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.

Polysiphonia forfex Harv.

This name is not current. Find out more information on related names.

Reference
Phycol.Austral.Pl. 2:Pl. 96 (1859)
Conservation Code
Not threatened
Naturalised Status
Native to Western Australia
Name Status
Not Current

Scientific Description

Habit and structure. Thallus red-brown, 1–5 cm high, with an erect basal axis, subdichotomously to laterally branched with usually patent branches, sometimes fastigiate and unilateral above, usually with somewhat forcipate or involute apices. Holdfast 1–3 mm across, of clumped rhizoids; epiphytic on Posidonia or larger algae. Structure. Basal axis 300–700 µm in diameter with segments L/D 0.3–0.5, with rhizoids cut off from the pericentral cells or cortical cells of the basal segments; mid branches 300–500 µm in diameter with segments L/D 0.3–0.5, tapering to 100–150 µm in diameter with segments L/D 0.2–0.3 shortly behind the apices, then tapering abruptly to the involute apices, with relatively inconspicuous trichoblasts; lateral branches several to many segments apart, arising in place of trichoblasts; cicatrigenous branches occasional. Pericentral cells 6 occasionally 5 or 7, isodiametric to slightly broader than long in face view, and commonly in longitudinal rows but sometimes irregular, lightly corticate near the base of main axes with relatively large cells cut off from the sides of the pericentral cells; trichoblasts or scar cells on every segment, trichoblasts slender (basal cells 15–20 µm in diameter), 3–5 times furcate. Rhodoplasts elongate-ovoid to ribbon-like.

Reproduction. Gametophytes dioecious. Carposporophytes with a small basal fusion cell and short gonimoblast bearing clavate terminal carposporangia 35–50 µm in diameter. Cystocarps short-stalked, subspherical to ovoid, 250–400 µm in diameter; pericarp ostiolate, 2 cells thick, outer cells angular, isodiametric, with the apical ostiolar cells becoming enlarged. Spermatangial branches replacing the whole trichoblast, elongate-ovoid, 120–270 µm long and 70–120 µm in diameter. Tetrasporangia forming spiral series in upper branches, with a divergence of about one fifth owing to irregularly placed pericentral cells, often descending below 1–2 branchings, not or very slightly distorting the segments and occupying only 0.3–0.5 the branch diameter, 55–110 µm in diameter.

Distribution.Coast near Fremantle, Rottnest I.,Garden I., and King George Sound, W. Aust.

Habitat. Epiphytic on Posidonia and some robust algae.

[After Womersley, Mar. Benthic Fl. Southern Australia IIID: 202–204 (2003)]