- Reference
- Syll.Alg. 1415 (1903)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus red, delicate, with prostrate axes bearing erect laterals 5–25 mm high with dense apical tufts of decussate whorl-branchlets with mostly alternate distichous pinnules. Attachment by rhizoids from the small basal cells of whorl-branchlets, developing a branched digitate hapteron on the host; epiphytic. Structure. Apical cells 5–10 µm in diameter and L/D 1–2, enlarging below to 40–65 µm in diameter and L/D 2–4(–6), and to 90–180 µm in diameter and L/D (1.5–)2–4 in lower erect and prostrate axes; whorl-branchlets formed in decussate pairs, (500–) 600–1200(–1700) µm long, basal cells isodiametric, 15–35 µm in diameter, pinnules distichous and alternate [occasionally 1(–3) opposite pairs basally], unbranched or with simple branches; cells of rachis above basal cells 20–35 µm in diameter and L/D (2–)3–4, decreasing in the pinnules to 8–10 µm in diameter and L/D 3–8 several cells below the apices; gland cells scattered, sparse, borne on short 2(–3)-celled branches on the pinnules, 10–15 µm in diameter.Lateral branches arise irregularly from the basal cells of whorl-branchlets. Cells uninucleate; rhodoplasts ovoid, elongate in larger cells.
Reproduction. Gametophytes dioecious. Procarps successive below indeterminate apices, with the basal cells of whorl-branchlets acting as supporting cells and bearing 4-celled carpogonial branches. Post-fertilization union with the auxiliary cell occurs via a connecting cell and the auxiliary cell divides to form a foot cell and upper cell which produces a terminal gonimolobe 250–450 µm across of ovoid carposporangia 15–45 µm in diameter, occasionally with later gonimolobes laterally; the axial cell, supporting cell and foot cell usually fuse together, and the carposporophyte is surrounded by an involucre of filaments. Spermatangia occur on special short branches on lower cells of the pinnules, in heads 25–35 µm in diameter and L/D 1.5–2.5, with a central axis of 5–10 cells bearing whorls of 4–6 cells with terminal spermatangial. Tetrasporangia are usually borne on lower cells of the pinnules, ovoid, 35–75 µm in diameter, sessile, decussately or cruciately divided.
Distribution. Shark Bay, W. Aust., to Westernport Bay, Vic., and N Tas.
Habitat. This species grows on a variety of hosts.
[After Womersley, Mar. Benthic Fl. Southern Australia IIIC: 112–114 (1998)]