- Reference
- Smithsonian Contr.Mar.Sci. 27:56 (1987)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus with a prostrate system attached by rhizoids arising from nodal cells, with 1–3 rhizoids per node, these with multicellular digitate pads. Erect axes simple or sparingly subdichotomously branched, to 2–3 mm tall, with straight or slightly curved apices. Occasional adventitious branches present, these slightly thinner at the junction with the bearing branch; nodal cortication near apices and in lesser branches 70–90 µm in diameter, in mature axes to 150 µm in diameter and occasionally extending to cover the axial cells. Structure of nodes with 6 or 7 periaxial cells, forming paired acropetal and basipetal cells, these dividing further and eventually covering the periaxial cells. Mature nodal bands cupulate, with 6–10 cells layer, but these not regularly aligned; gland cells occasionally present. Acropetal margin of nodal bands with a ragged edge, whereas the basipetal edge is smooth.
Reproduction. Tetrasporangia arising acropetally in whorls of 6 or 7 on successive distal nodes of erect axes, 35–45 µm long, 30–35 µm in diameter, cruciately divided, with involucral filaments covering the majority of the sporangium, the entire structure forming a stichidium-like head. Other reproduction not observed.
Distribution. Widespread in the tropical waters of the Indian and Pacific Oceans and the Caribbean; previously known from eastern Australia but newly recorded for W. Aust. In north-western Australia known from Scott Reef and the Maret Is., but probably often overlooked.