Dictyota coriacea

Thallus flabellate, coarse, coriaceous, creeping and erect, 6-25(-40) cm high, light brown, olive when young and dark brown in older plants. Branching dichotomous, subdichotomous, with narrow axils. Branches strapshaped with entire margins, rounded apices, 0.5–1.3 cm wide, 300-500 mm thick. Cortex composed of 1-2(-3) small, heavily pigmented cells. Medulla composed of one layer of longitudinally elongated rectangular cells becoming two-layers near the margins. Reproductive organs (tetrahedrally divided monosporangia, antheridial and oogonial sori) develop on both surfaces of the thalli except for the margins. Attachment by short stupose holdfast composed of multicellular filamentous rhizoids. Growing in clusters on rocks, in the lower intertidal to subtidal zones exposed to moderate wave action.

North and Central America, Asia (China, Japan, Korea).