- Reference
- Spec.Gen.Ord.Alg. 62 (1848)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus medium brown when young, becoming dark brown when older and thicker, a few mm to 5 cm across and (100–)150–400(–500) µm thick, crustose and not gelatinous, surface smooth to slightly verrucose when older, margin circular when young but becoming irregular with age, often slightly concentrically zoned, tightly adherent to the rock, shell or wood substrate, often overgrowing older thalli. Basal layer of radiating filaments, without rhizoids, slightly assurgent at the several-layered margin and moderately to strongly radially assurgent within the margin with cells 4–10(–12) µmacross and L/B 2–6(–8). Erect filaments continuing from assurgent filaments, closely adjacent and not separating readily under pressure, with cells 3–8(–10) µmin diameter and L/B 1–1.5(–2). Growth by divisions of apical cells of basal and erect filaments. Cells with a single, often irregularly shaped phaeoplast and several to numerous, usually prominent, physodes. Phaeophycean hairs in clusters, arising from basal layer or lower assurgent filaments.
Reproduction.By plurilocular sporangia forming small to spreading surface sori, each sporangium uniseriate (rarely with occasional biseriate locules) from an erect filament, 50–100 µmlong with 8–14(–20) locules and 3–5(–8) µmin diameter, with a terminal sterile cell. Unilocular sporangia in surface sori, each accompanied by a cylindrical to slightly clavate paraphysis 80–120 µm and 6–8 cells long; sporangia elongate-ovoid to clavate, 70–90 µmlong and 18–26 µmin diameter.
Distribution. All along southern Australia, from at least Cowaramup Bay, W.Aust., to Broken Bay, N.S.W. and around Tas.
[After Womersley, Mar. Benthic Fl. Southern Australia II: 70–72 (1987)]