Liagora australasica Sond.

Scientific Description

Habit and structure. Thallus to 7 cm high, pale reddish brown to pink, moderately to heavily calcified, dichotomously branched every 1.5–8.0 mm. Axes 0.5–1.0 mm in diameter, tapering slightly at the apices. Medullary cells 5–20 µm in diameter. Assimilatory filaments dichotomously or trichotomously branched, mostly near periphery; lower cells elongate and cylindrical; upper cells becoming shorter and ovoid, 5–10 µm in diameter; terminal cells subspherical, 4–7 µm in diameter.

Reproduction. Monoecious. Spermatangia borne on spermatangial mother cells arising on apical and subapical cells. Carpogonial branches 3- or 4-celled, strongly curved, on the distal region of the supporting cell. Post-fertilisation involucral filaments arising from cells adjacent to the supporting cell and enveloping the developing carposporophyte; involucral filaments branched, initially of slender cells, but becoming broader as the cystocarp matures. Gonimoblast compact or slightly diffuse, with a fusion cell.

Distribution. Occurs from the Dampier Archipelago to Rottnest I., W. Aust.; also in Bowen, Qld and Lord Howe I.

Habitat. Epilithic or epiphytic on Amphibolis stems, usually in shallow water, but collections have been made from depths to 13 m.