- Reference
- Austral.J.Bot.Suppl.Ser. 56 (1972)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus mid red-brown to (commonly) grey-red, (5–)10–15 cm high, sparsely and irregularly branched, with prostrate axes attached by haptera; epiphytic, usually on Amphibolis. Structure. Sub-apical cells bearing 4–5 whorl-branchlets, when mature subdi- or trichotomously branched and incurved, with adjacent whorls regularly imbricate along the whole axis often with trapped sand grains; branches tapering only slightly, axial cells 200–500 µm in diameter, and L/D 3–5, terminal cells with rounded ends, median cells 50–60 µm in diameter and L/D 3.5–5. Indeterminate branches arising in positions of whorl-branchlets. Cortication rare, only near base of thallus, rhizoidal. Cells multinucleate; rhodoplasts discoid.
Reproduction. Gametophytes dioecious. Female axes with 2 short terminal cells and the longer hypogenous cell bearing a single involucral filament, with the subapical cell bearing 2 sterile pericentral cells and a supporting cell with a sterile apical cell, and a lateral carpogonial branch. Development as in M. protensum with the fusion cell producing gonimoblast cells, carposporophytes 650–1100 µm across with terminal clavate carposporangia 30–40 µm in diameter; the sterile cells of the procarp produce 4 inner involucral branchlets. Spermatangial heads are subspherical, 45–90 µm in diameter, terminal on short cells borne on cells of the whorl-branchlets. Tetrasporangia are formed terminally or laterally on small cells borne on lower cells of the whorl-branchlets, 50–60 µm in diameter, tetrahedrally divided.
Distribution.Rottnest, I., W. Aust., to San Remo, Vic., and Robbins I., N Tas.
[After Womersley, Mar. Benthic Fl. Southern Australia IIIC: 95 (1998)]