Betaphycus gelatinus

Thallus decumbent, large, fleshy, coarse, leathery, forming entangled hemispherical masses to 20 cm in diam., yellowish-green to dark-purple color. Branching irregularly dichotomous or pinnate. Axes compressed, 3-5 mm broad, 1-2 mm thick, accreted or free, gradually tapering to the tops, with spinous outgrowths (or tubercles) on ventral surface and marginal sides of thallus (dorsal side usually smooth), which are simple or like knobs or cylindrical protrusions, 2-3 mm long. In transverse section, medulla composed of numerous rhizoidal cells; inner cortex of many rows of large (round, ovoid or polygonal cells) and outer cortex consists of 2-3 rows of small densely packed cells. Cystocarps develop on tops of tubercles on the ventral surface. Attachment by hapters originating from underneath of thallus. Growing in the intertidal to upper subtidal zones, of shores exposed to strong wave action.

Tropics and subtropics of Indian and Pacific Oceans.