Chondrus giganteus

Thallus cartilaginous, fleshy-membranaceous thick-leathery, bushy, in tufts, 10–50 cm high, dark purplish-red to greenish-yellow color. Blades flat linear-lanceolate, ~6 cm broad, with cuneate extended base, simple or repeatedly dichotomously or subdichotomouly branched with simple or furcate apices. Margins entire or with oblong or linear-sigmoid, compressed at the base prolifications. In cross section, Tetrasporangia rounded, cruciately divided, develop in tetrasporangial sori scattered over the thallus (visible as dark-red spots). Cystocarps large, ocellatus, roundish to subelliptical, slightly prominent from both sides of the thallus, 1–3 mm across. Attachment by small discoid holdfast. Growing on rocks in the lower intertidal and subtidal zones.

Europe (France), Asia (Japan, Korea).