- Reference
- Spec.Gen.Ord.Alg. 662 (1852)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus medium red to yellow-red or red-brown, 10–25(–50) cm high and 10–30 cm across, membranous, foliose and usually much branched with marginal lobes for 2–3 orders, complanate but the lobes often convolute or ruffled, lesser lobes 5–15 mm across, apices rounded; veins absent. Stipe 2–15 mm long, slender. Holdfast small, discoid becoming fibrous; epiphytic on seagrasses (Posidonia and Amphibolis) or larger algae. Structure. Growth marginal and intercalary, without or with occasional apical cells, primary cells becoming irregularly placed more-or-less in rows, angular, isodiametric to slightly elongate, 20–30 µm across, blades mostly monostromatic, 35–50 µm thick, becoming polystromatic below, cortical cells equivalent; margin of blades smooth or with slight dentations. Cells multinucleate; rhodoplasts discoid, becoming chained.
Reproduction. Gametophytes dioecious. Procarps scattered, on opposite sides of the thallus from one primary cell which cuts off a cover cell which divides into 2(–3) and a supporting cell which produces a 4-celled carpogonial branch and a 2–3-celled sterile group, with the carpogonial branch lying between the cover cells and the sterile group. Carposporophyte with a small basal fusion cell and much branched gonimoblast with clavate to pyriform terminal carposporangia 30–45 µm in diameter. Cystocarps 1–1.5 mm across, slightly swollen with a slight collar; pericarp ostiolate, 3–5 cells thick, cells in regular tiers. Spermatangial sori scattered, elongate 0.4–1 mm across, with the primary cell producing a layer of cortical initials which cut off elongate spermatangia, often in blocks corresponding to the primary cells. Tetrasporangial sori scattered, ovate, 0.2–1 mm across, with tetrasporangia cut off from the primary cells and lying in gaps between these cells, more-or-less in one layer; tetrasporangia subspherical, 45–90 µm in diameter.
Distribution. N and E coasts of Tas., probably also from Port Elliot, S. Aust., and Seaholme to Point Hicks, Vic.
[After Womersley, Mar. Benthic Fl. Southern Australia IIID: 119–122 (2003)]