Filaments branched, forming dark green, slippery bushy tufts, up to 6 cm long; prostrate system consisting of irregularly branched filaments attached by rhizoids; erect system with main axes alternately divided, secondary branches mostly opposite or whorled developed from barrel-shaped axial cells and ending in a blunt or a hyaline seta; cells of main axes 10-18 µm wide, 12-30 µm long, 0.5 to 3 times longer than wide, often a series of several barrel-shaped cells alternating with more cylindrical cells; cells of secondary branches 6-10 µm wide, about equal in length and breadth, thin-walled; chloroplast parietal with 1 to several pyrenoids.