Scinaia okamurae

Thallus bushy, forming hemispherical clumps, to 10 cm high, pinkish to dark purplish-red. Branching regular repeatedly (~8–12 times) dichotomous. Branches composed of soft cylindrical isodiametric segments, without constrictions at joints, 1–2 mm diam., slightly tapering to apices in the uppermost segments. The uppermost segments bifurcate with pointed apices. In transverse section, surface cells unpigmented, near to oval; subsurface cells 1(–2) rows of near to oval, densely pigmented cells and cells of slender rhizoidal filaments; medulla composed of long colorless thick-walled dichotomously branched filaments. Attachment by small discoid holdfast. Growing on hard substratum in the lower intertidal to upper subtidal zone of sheltered coasts.

Pacific coast of Japan, west coast of Kushu Island; Korea.