Colpomenia sinuosa

Thallus solitary or gregarious, hollow, spherical, hemispherical, becoming lobed or irregularly expanded to 10-30 cm diam., light- or golden-brown to greenish-brown. Membrane 300-500 mm thick. Cortex consists of 1(-2) layers of small cuboidal or polygonal pigmented cells, 3.5-7.5 mm diam. Medullar colorless cells (of 5-7 layers) irregular in shape, rounded polygonal, to 180 mm, gradually decreasing in size towards the cortical layer. Fine, colorless hairs in tufts, scattered on the surface of the thalli. Plurilocular gametangia cylindrical to club-shaped, 4-7.5 mm diam., 18-35 mm long, occur in dense superficial sori, (100-400 mm diam.), scattered over the surface of the thallus. Paraphyses obovate, to 11 mm diam., 50 mm long. Growing on hard substrate, epiphytic, intertidal.

Cosmopolitan, from Antarctic to tropical latitudes.