Laurencia okamurae

Thallus fleshy to cartilaginous, bushy, 10-20 cm high, with several erect axes densely tufted below with coalesced basal branches, purplish-red to greenish color. Main axes to 2 mm diam. at basal portion, percurrent and bearing alternate, opposite or sometimes subverticillate branches from three sides with paniculate outline. Branching repeatedly pinnate. Ultimate branchlets, cylindrical, clavate becoming shorter toward the top. Apices roundish or truncate. In transverse section, cortical layer composed of roundish to near quadrate cells, ~32×35 mm, followed by roundish to angular becoming larger to the medulla. Lenticular thickenings present in cell walls of the medulla. Sporangia tetrahedrally divided, ~100 mm in diam., located near the apices of terminal branchlets (converted into stichidia), Cystocarps ovoid, to 820 μm diam., lateral on branchlets. Growing on rocks in lower intertidal and upper subtidal.

Europe, China, Taiwan, Japan, Korea, Philippines, Pacific Islands.