Gloiopeltis tenax

Thallus cartilaginous, slippery, bushy, erect, 3.5-12(-20) cm high, 0.8 mm thick, commonly gregarious, dark reddishpurple, to almost black when exposed to air. Branching irregularly dichotomous. Branches cylindrical at base and compressed above, 1.5-2.5(-4) mm broad, attenuate towards apices. In transverse section, medulla consists of axial cell and filaments, ~9-11 mm diam., of uniseriate cells, (1.8-2.5×10 mm); cortex ~250 mm thick, composed of inner cortex of loosely arranged small oval to roundish cells, 6-7.5×7.5-10.5 mm and outer cortex of firmly compacted elongated cells, 2.7-4×6-10 mm. Terasporangia roundish, ovoid to oval, cruciately divided, 22-29×32-50 mm, scattered mostly in the inner cortex. Cystocarps hemispherical, prominent, 190-300(-400) mm diam. Growing on lower intertidal rocks, in semi-sheltered and open areas.

Russia (Kamchatka), China, Taiwan, Japan, Korea, Vietnam, Philippines, Indonesia.