Gelidium pacificum

Thallus bushy, robust, cartilaginous, caespitose, grayish-green to dark purple-red, 10-20(-35) cm high, pyramidal in outline. The main axes flattened throughout, linear, 1.5-2.5(-3) mm wide, branching to four orders in opposite or alternate manner. The main branches flexuosus and narrower than the main axes. Ultimate branchlets clavate, often at right angle. Branches and branchlets distichous, directed upward. At the base branches slightly incurved, with rounded sinuses. In transverse section, cortex composed of 2-3 rows of rounded cells; a medulla composed of large colorless cells surrounded by dense rhizoidal filaments. Tetrasporangia develop in rounded sori, 25-30×33-37 mm. Cystocarps develop in branchlets below apices. Attachment by fibrous discoid holdfast composed of creeping axes with peglike rhizoids. Growing on rocky substratum, in the low intertidal and upper subtidal zones.

China, Taiwan, Japan, Korea, Russia (the Sea of Japan).