Colpomenia peregrina

Thallus spherical, sack-like, bladderlike, hollow, thin-coriaceous, smooth, light golden-brown or olive, up to 10 cm in diam., with age becoming wrinkled, lumpy, often with subsided walls. In transverse section, the membrane consists of 1-2 layers of small cortical cells (15–18×18–30 mm) and 3-4 layers of inner large roundish thin-walled cells, to 175 μm in diam. Fine colorless hairs (in clusters) are developed from subcortical cells. Paraphyses abundant, to 40 μm long, and to 15 μm diam. Attachment by small base. Growing in low intertidal, intertidal pools and subtidal, on rocky, stony and sandy-muddy bottom with stones or often on larger algae (Sargassum pallidum, Stephanocystis crassipes), in sheltered, semi-sheltered and open shores. It occurs single or in groups, forming a solid dense clusters.

Europe, Mediterranean, North and Central America, Africa, Asia (Japan, Korea, Russia), Australia and New Zealnad, Pacific Islands.