- Reference
- Ofversigt af Forhandligar: Kongl. Svenska Vetenskaps-Akademien 445 (1870)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus medium to dark brown, 40–100 cm (–2.5 m) long, fairly openly branched in one plane. Holdfast discoid-conical, 0.5–1.5 cm across, with a single stipe; epilithic. Primary axes relatively straight, quadrangular to almost square in transverse section (W/T1–1.5) with rounded corners, tapering gradually above, 2–5 mm broad and thick, alternately distichously branched from the face; secondary axes not or only slightly retroflex, 5–10 cm long and 1–2(–3) cm apart, sometimes developing into long main axes; lower secondary axes and laterals usually lost, with short, stumpy, residues 1–4 mm apart and 0.5–1.5 mm long. Laterals (2–)3–5(–8) cm long, usual1y alternately distichous, becoming subdichotomous, with rounded axils; ramuli linear, terete to slightly compressed, 0.5–3 cm long, 0.3–0.8 mm in diameter. Vesicles absent.
Reproduction. Thalli dioecious. Receptacles mostly simple, straight to undulate, 3–8 cm long and 1–2 mm broad, slightly to distinctly compressed, attenuate at both ends. Conceptacles with ostioles in two rows on the margins, slightly swollen and separated by sterile tissue, unisexual; oogonia sessile, ovoid, 100–140 µm long and 70–100 µm in diameter, with simple paraphyses; antheridia on branched paraphyses, ovoid, 25– 30 µm long and 10–12 µm in diameter.
Distribution.From Geographe Bay, W. Aust., to Wilsons Promontory, Vic., and the N coast of Tas.
[After Womersley, Mar. Benthic Fl. Southern Australia II: 394 (1987)]