- Reference
- Univ.Calif.Publ.Bot. 528 (1996)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus dark red-brown, 8–30(–50) cm high, much branched irregularly radially with a well developed, heavily corticated axis, usually branched in older plants, laterals branched for 2–4 orders, often proliferous from lower axes in larger plants. Upper branches clothed with trichoblasts for up to 2 cm from apices, denuded below, older axes smooth, 1–2 mm in diameter. Plants on rough-water coasts usually have the lower axes clothed with branched processes 1–3 mm long, branches 100–300 µm in diameter. Holdfast discoid, 1–10 mm across; epilithic. Structure monopodial, trichoblasts cut off from segments 4–8 in spiral sequence, pericentral cells 5, cut off from segments 8–15. Cortication commencing many segments below apices, with the pericentral cells remaining clear in transverse section and usually becoming thick walled, cortex small-celled. Trichoblasts rhodoplastic, 0.8–1.5 mm long, straight or often strongly incurved, branched several times 1–6 cells apart, tapering evenly from 30–50µm in diameter below to 5–7 µm in subterminal cells (lost from older trichoblasts), basal cells L/D 1–1.5(–2), mid cells L/D 2–3, upper cells L/D 4–10. Laterals arising on basal cells of trichoblasts. Cells uninucleate in trichoblasts; rhodoplasts discoid, becoming chained.
Reproduction. Gametophytes dioecious. Procarps on the next to basal cell of trichoblasts, which becomes polysiphonous. Carposporophytes with a basal fusion cell and much branched gonimoblast filaments with clavate terminal carposporangia 25–55 µm in diameter. Cystocarps globose to urceolate, sessile, 600–1000(–1200) µm in diameter, with a slight neck; pericarp ostiolate, 3–4 cells thick, corticated except on the neck. Spermatangial organs on lower branches of trichoblasts, cylindrical, 100–220(–300) µm long and 35–50 µm in diameter. Tetrasporangia borne in lesser branches with trichoblasts, spirally arranged, one per segment, fertile parts (0.7–)1–2(–2.5) mm long and 150–300 µm in diameter; tetrasporangia 70–120 µm in diameter, with 3 cover cells.
Distribution.Eyre, W. Aust., to Western Port, Vic., and N Tas.
[After Womersley, Mar. Benthic Fl. Southern Australia IIID: 253–257 (2003)]