Grateloupia acuminata

Thallus blade-like, soft-cartilaginous, narrowly lanceolate to linear, simple, forked or incised into several blades at the top, 20-40(-60) cm long, 0.8-1.6(-6) cm wide, dark purple-red, proliferous at margins (sometimes from the surface). Blade with narrowly cuneate base and small holdfast. Proliferations narrowly lanceolate or linear to very narrow, alternately-pinnate, 0.2 to 1.2 cm long. Inner structure composed of cortex and medulla: cortical filaments consist of 5–8 cells of outer (to 5.5×11 μm) and inner cortical cells (15–25 μm in diam.). Medulla composed of colorless filaments (to 8.5 μm width) and stellate cells. Carposporangia to ~20×35 μm. Tetrasporangia cruciately divided to ~23×48 μm. Growing in the low intertidal and upper subtidal (1-2 м), on rocky, boulders and stony bottom in open coastal areas.

Countries of the Asia-Pacific Region: China, Korea, Japan, Russia (Peter the Great Bay, the Sea of Japan, Sakhalin Island, Moneron Island), Indonesia, Philippines.