- Reference
- Austral.J.Bot. 293-295, fig18K-N (1968)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus with prostrate axes bearing numerous erect lateral branches up to 4 mm long, with opposite, decussate, whorl-branchlets (pinnae) from each axial cell, curving upwards towards the branch apex. Attachment by rhizoids from the basal cells of pinnae with digitate haptera; epiphytic on geniculate coralline algae. Structure. Apical cells 4–5 µm in diameter and L/D 0.7–1.2, surrounded by young whorl-branchlets and enlarging to 60–90 µm (including a thick sheath) in diameter and L/D 0.7–2 in mature axial cells. Pinnae 200–450(–580) µm and 10–15 cells long, basal rachis cells 25–32 µm in diameter and L/D 1–1.5, tapering to terminal cells 6–9 µm in diameter and L/D 1–1.5, each of the lower 2(1–3) cells with opposite pinnules and upper cells with alternate pinnules, pinnules 10–22 µm in diameter, cells L/D 1–1.5(–2), tapering to their apices, usually with 1–3 simple branches in the plane of the pinnae; gland cells occur on short 2–3-celled branches on the sides of pinnules. Lateral branches arise at irregular intervals on the short basal cells of pinnae. Cells uninucleate; rhodoplasts discoid to elongate, ribbon like in larger cells.
Reproduction. Carpogonial branches occur in series of 4–8 on the basal cells of pinnae near branch apices which then cease elongation. Slight fusions only occur between the axial cell, supporting cell and other lower gonimoblast cells, and a terminal group 100–250 µm across of ovoid carposporangia 15–30 µm in diameter develops, followed by lateral groups.Spermatangia unknown. Tetrasporangia unknown in the type.
Distribution. Known from the type locality (Middle R., Kangaroo Island, S. Aust.) and Shark Bay, W. Aust.
Habitat. Epiphytic on geniculate coralline algae.
[After Womersley, Mar. Benthic Fl. Southern Australia IIIC: 112 (1998)]