Dictyota humifusa

Appearance

Thallus: prostrate, delicate, creeping, densely interwoven, to 0.5-2.0 cm high, light brown, often with bril­liant blue iridescence; branching irregular to somewhat dichotomous. Blades stubby, strap-shaped, (1-)3-5 mm wide, 75-125 µm thick, 30-60 medullary cells wide; apices broad, rounded. Medulla one cell thick: cells square to rectangular, 40-80 µm thick, arranged in somewhat regular rows. Surface cells rectangular, 10-30 µm thick, in parallel rows. Surface hairs tufted, scattered, seldom present. Rhizoids from lower surface, seldom marginal. Sporangia scattered, with four or eight spores.

Distribution

Predominantly found in tropical and sub-tropical seas.

Habitat

Common: tightly adhering to any firm substrate, creeping over surfaces, in shallow protected habitats; to 40 m deep.