Rhodymenia intricata

Thallus flat, flabellate, 2-5(-8) cm high purplish-red color. Branching dichotomous, irregularly dichotomous (3-8 times), in one plane. Branches strap-shaped, 2-4(-6) mm broad with rounded apices. Margins entire, smooth. Cortex of 2 rows of small roundish to oval cells, 3-4×4-8 mm; medulla composed of 3-5 rows of larger irregularly roundish to angular cells, 20-48×60-76 mm (largest inwardly, central cells to 70×200 mm). Tetrasporangia cruciately divided, 13-16 mm diam., on both sides of upper branches. Cystocarps hemispherical, ~700 mm diam. Attachment by disc-like holdfast to hard substrate.

In temperate, subtropical and tropical latitudes of Pacific Ocean.