- Reference
- Syn.Alg.Scand. xii (1817)
- Conservation Code
- Not threatened
- Naturalised Status
- Native to Western Australia
- Name Status
- Current
Scientific Description
Habit and structure. Thallus pale to medium brown, occasionally drying green, erect, to 50 cm tall, attached by a narrow rhizoidal holdfast, composed of a single percurrent primary axis (150–) 175–400 (–700) µm diam. proximally, giving rise to 1 order of indeterminate laterals, each characterised by many close-set and patent determinate branchlets. All branches irregularly alternate, radially arranged, flaccid and terete throughout. Indeterminate lateral branches long and filiform, (60–) 80–240 (–275) µm diam., densely beset with fertile determinate branchlets, (4–) 7–20 (–34) branchlets per centimetre. All branches terminated by short tufts of trichothallic assimilatory filaments 3–5 (–8) mm long; filaments fine, each with a meristem 5–9 cells above its base, the distal cells (60–) 90–130 (–170) µm long, (12–) 14–20 (–22) µm diam. [L:B 4–10 (–12.5)]. Medullary cells cylindrical, (130–) 160–290 (–400) µm long, 20–40 (–48) µm diam., with thickened and hyaline cell walls. Cortex smooth, a single layer of cuboidal to rectilinear cells 16–36 (–52) µm long and (8–) 12–16 (–20) µm diam. [L:B 1–3 (–6)], arranged in regular liner columns. Sori ovoid to clavate, 0.35–1.60 (–2.00) mm long, 0.15–0.40 mm diam. [L:B 3–7 (–10)], borne on a sterile stalk 0.2–0.8 (–1.0) mm long, developing on determinate branchlets 0.65–1.60 (–2.50) mm long and 50–100 (–300) µm diam. and spaced 0.35–2.60 (–4.80) mm apart. Paranemata densely aggregated, 3–5 (–6) cells and 75–110 (–120) µm long, mostly simple but occasionally branched, terminated by an inflated subspherical to obpyriform cell. Unilocular sporangia sessile, (14–) 20–40 (–48) µm long, 6–12 µm diam. [L:B 1.6–4.5 (–6)], borne in lateral clusters on lower cells of paranemata.
Distribution. Virtually cosmopolitan from cold-temperate to tropical waters
Habitat. Subtidally on rock or shell fragments surrounded by unconsolidated sand or mud.
[After Yee, Millar & Huisman, Algae of Australia: Mar. Benthic Algae of North-western Australia, 1. Green and Brown Algae 242 (2015)]