Padina arborescens

Thalli coriaceous, 15–20 cm high. Blades fan-shaped, 10-30 cm diam., entire or shallowly split at margins, senescent thalli split into several lobes. Outer margins inrolled. The base of the thalli stypose covered with brown hairs. In cross section, blades to 100 mm thick (of 2–3 cell layers) at margin and to 380 mm thick (10–12 cell layers) at base. Surface hairs in concentric lines. All reproductive structures develop on the upper surface of thalli: tetrasporangia oval, densely grouped in sori; oogonia obovate, in ellipsoidal sori covered with indusium; anteridia oblong, in swollen roundish sori. Attachment by stypose holdfast. Growing on middle intertidal to subtidal rocks.

China, Hong Kong, Korea, Japan, Taiwan.