Colpomenia sinuosa (Roth) Derbès & Solier

Scientific Description

Habit and structure. Thallus medium to dark brown, sessile with a broad base, 2–15 cm (–1 m) across and 1–4(–8) cm high, irregularly globular, lobed, convolute or folded, membranous and firm when living, hollow, epilithic or epiphytic. Structure of larger, clear, inner medullary cells, 4–6 cells thick, and a cortex 1–2 cells thick of small isodiametric cells 9–12 µm across in surface view, each with a single phaeoplast and pyrenoid; phaeophycean hairs in scattered groups, (5–)8–10(–12) µm in diameter.

Reproduction. Sori mostly punctate, usually discrete and mostly 200–400 µm across, developing around hair groups, covered when young by an overall cuticular membrane which later ruptures. Plurilocular reproductive organs uniseriate or with occasionally divided locules, 30–40 µm and 6–10 locules long, 4–5 µm in diameter, 2 or 4 rows arising from each cortical cell, accompanied by scattered, clavate, unicellular paraphyses (25–)30–50 µm long and 8–16 µm diameter, L/B 3–4, with dense physodes.

Distribution. Generally around the Australian Coast.

Habitat. From the mid eulittoral to below low tide level, mainly in summer.

[After Womersley, Mar. Benthic Fl. Southern Australia II: 297 (1987)]