Mazoyerella australis (Harv.) Huisman & Womersley

Scientific Description

Habit and structure. Thallus medium to dark red, erect, 5–9 cm high, ecorticate, subdichotomous and often flabellate. Attachment by short descending rhizoids from basal cells; epiphytic or possibly epilithic. Structure. Apical cells 20–80 µm in diameter and L/D 2–10, increasing to 120–150 µm in diameter and L/D 3–6 in the central thallus and 200–600(–800) µm in diameter and L/D 4–10 near the thallus base. Cells multinucleate; rhodoplasts discoid to elongate, ribbon like in larger cells.

Reproduction. Propagules arising on subapical cells, when mature with a stalk cell 40–70 µm long and 35–60 µm in diameter, subtending an ovoid propagule 70–120 µm in diameter and 180–270 µm long, with the parent cell developing a lateral branch so that the propagule appears auxiliary. Propagules with 20–50 nuclei and numerous small vacuoles, stalk cell with 4–5 nuclei. Gametophytes known only in culture. Female axes of 2 cells and a larger hypogenous cell. Subapical cell with 2 periaxial cells, one (the supporting cell) bearing a 4-celled carpogonial branch and a terminal sterile cell. Post-fertilization stages unknown. Spermatangial heads ovoid, sessile, 90–100 µm in diameter, with 5–6 axial cells bearing whorls of cells and ultimate spermatangia. Polysporangia subspherical to slightly ovoid, situated in branch axils, 90–120 µm in diameter, with 8 spores.

Distribution.Rottnest I., W. Aust., to Westernport Bay, Vic.

[After Womersley, Mar. Benthic Fl. Southern Australia IIIC: 302–305 (1998)]