Halymenia malaysiana P.L.Tan, P.E.Lim, Showe M.Lin & Phang

Scientific Description

Habit and structure. Thallus erect, foliose, pale pink to red, generally mottled, to 15 cm tall. Blade mostly entire, but sometimes irregular in outline, with a smooth surface and entire to minutely dentate margins; stipe absent. Structure with a filamentous medulla; most filaments anticlinally orientated and 2–5 µm diam.; ganglionic cells also present. Cortex with an inner layer of stellate cells, subtending an outer cortex 2 or 3 cells thick; outermost cells 9–11 µm long and 4–7 µm diam., occasionally pointed; surface cells more elongate when associated with tetrasporangia.

Reproduction. Cystocarps immersed, with a somewhat ellipsoidal gonimolobe c. 100 µm tall and 60 µm broad. Tetrasporangia scattered, borne on cells subtending surface cells, ellipsoidal, 20–25 µm long, 15–18 µm diam., cruciately or decussately divided. Other reproductive structures not observed.

Distribution. In north-western Australia known from Broome, Long Reef and Cassini Island, also Malaysia, the Philippines and Indonesia.

Habitat. Epilithic in the intertidal and subtidal.

[After J.M. Huisman & O. De Clerck in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 288–290 (2018)]