Ceramium japonicum

Thallus bushy, tufted, coarse-filamentous, soft-cartilaginous, deep pinkish-red to purple color. Branching pinnate or on all sides, irregularly dichotomous, alternate, unilateral or opposite. The main axis and branches of the first order covered with short adventitious branches. Branches cylindrical, consisting barrel-shaped cells, 1–1.4 mm diam. at lower portion and ~ 600 mm above tapering to the base and apices. Branch apices straight, often forked unevenly and acute. Thalli with continuous dense cortex. Sporangia 46–60 μm diam. developing in cortical layer (mainly at cell joints). Cystocarps to 400×500 μm. Carpospores 25–40×38–70 μm. Attachment by tuft of rhizoids isuing from creeping axes. Growing on rocky, stony, muddy-sandy bottom with pebbles, shells, and epiphytic on larger algae in the intertidal and upper subtidal zones, in sheltered and semi-sheltered areas.

 Common in countries of the Asia-Pacific Region (China, Korea, Japan, Far East Russia).