Sargassum flavicans (Mert.) C.Agardh

Scientific Description

Habit and structure. Thallus pale brown, delicate, to 35 cm tall, with a discoid-crustose holdfast 5–8 mm wide giving rise to 1–3 terete primary axes covered in short branch scars 1–2 mm diam. Primary branches subterete to flattened when pressed, smooth or striated, with occasional cryptostomata, 0.8–1.5 mm diam. Primary laterals alternate, lanceolate, serrulate, occasionally divided, 22–45 mm long, 2–6 mm wide; apices obtuse or acute; base cuneate, subsymmetrical; cryptostomata small. Secondary branches alternate, compressed, smooth, 0.3–1.0 mm diam. Secondary laterals alternate, lanceolate, serrulate, occasionally bifid, 5–42 mm long, 1.5–8.0 mm wide; apices obtuse or acute with darker tips when immature. Vesicles smooth, spherical, 1.5–3.5 mm diam., occasionally with a spiny winged margin or mucro; stalk terete or flattened and leaf-like. Receptacles in tight cymose clusters associated with leaves and vesicles, smooth, globose, 0.25–0.50 mm long, 0.10–0.15 mm wide; all specimens immature.

Distribution. Known from several localities in the Indian and western Pacific Oceans. In Australia also reported as drift from the N.T.

Habitat. Epilithic in the subtidal.

[After Dixon & Huisman, Algae of Australia: Mar. Benthic Algae of North-western Australia, 1. Green and Brown Algae 270 (2015)]