- Reference
- Bot.Mag.(Tokyo) 11:13-14, Figs A-D (1897)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus brown-red, forming loose entangled mats 5–10 mm thick, composed of slightly arching, flat, linear branches 100–200(–300) µm broad, internodes 1–4 mm long between slightly constricted nodes; attached by uniseriate rhizoids from nodal pericentral cells; epiphytic on Avicennia pneumatophores or on mud below mangroves. Structure. Growth apical, with a dome-shaped apical cell cutting off axial cells and lateral and transverse pericentral cells, the lateral cells each producing 2 flanking cells, dividing once more in broader blades giving blades 5–7(–9) cells broad in the internodes; secondary pit-connections frequent. Blades monostromatic apart from the midrib, ecorticate, margins entire. Branching of blades exogenous near apices, with adventitious proliferous blades arising from nodal pericentral cells.
Reproduction. Gametophytes dioecious. Carpogonial branches cut off from transverse pericentral (supporting) cells after formation of a sterile cell, with a second sterile cell produced later. Gonimoblast much branched, with a basal fusion cell and chains of ovoid carposporangia. Cystocarps central on branch internodes, sessile, ovoid, with a pericarp 2–4 cells thick. Spermatangial sori produced on both sides of the blades, between the sterile midrib and margin, with spermatangia cut off from initials on the primary cells. Tetrasporangial sori 6–18 axial cells long, arising from second- and third-order cell rows, 1–4 cells broad on each side of the midrib including the lateral pericentral cells and submarginal cells; tetrasporangia subspherical, 35–50 µm in diameter.
Distribution.In southern Australia, known only from Barker Inlet, Port Adelaide, S. Aust., on Avicennia pneumatophores and Garden I., Port Adelaide, S. Aust., on mud under Avicennia and mid eulittoral on a hulk. SE Asia, W Africa, Brazil, Peru, western Pacific, W subtropical Atlantic, eastern Australia.
[After Womersley, Mar. Benthic Fl. Southern Australia IIID: 25 (2003)]