Chaetomorpha linum

Thallus filamentous, stiff, gregarious, shining bright green to dark green. Filaments unbranched, coarse, twisted, loosely tangled, 10-40 cm long. In the lower part cells cylindrical, with slight constrictions at joints, 100-130(-350) mm diam., (0.5)-1-3 diameters long, cell wall thick, 13-20(-35) mm. Above cells cylindrical, slightly swollen, 300-500(-900) mm diam., (0.5)-1-2(-3) diameters long, constricted at cell joints, cell wall thin. Basal cell (60)-100-240 mm in diam., 300-900 mm long, ending into lobed haptera. Growing on rocky, sandy-muddy bottom with stones and shells, epiphytically on larger algae, in the middle intertidal to subtidal, forming floating and free lying intertwined masses in calm shallow pools.

Arctic to temperate waters in south hemisphere. Common in countries of the Asia-Pacific Region (Russia, Japan, China, Korea, Vietnam, Thailand, Indonesia, Philippines, Singapore, Australia and New Zealand, Pacific Islands).