Grateloupia imbricata

Thallus bushy, cartilaginous, leathery, 5-15 cm high, 220-400 mm thick, dark purple-red to orange-red color, palmately, irregularly dichotomously branched, branches widely-cuneate. In transverse section, cortex composed of outer 3-6 rows of oval to elongated densely compacted cells, 2.5-4×7.5-10 mm; inner cortex of 2-3 rows of roundish cells (5-10 mm diam.) loosely arranged; outer medulla of irregularly shaped cells, 15×20-22 mm; central medulla of loosely arranged long cellular filaments (5 mm diam.). Tetrasporangia oval, ovate, 20-23×46.2 μm, cruciately divided, scattered in outer cortex. Cystocarps spherical, to 400 μm diam., imbedded in medulla. Attachment by discoid holdfast. Growing on rocks in the lower intertidal zone.

Japan, Korea, China.