Padina boryana

Thallus blade-like, flabellate, often split into lobes in the upper portion, with entire margins, (3)-5-10 cm high, to 8 cm broad, yellowish-brown. Lightly calcified on the upper surface only. In cross section, blade composed of 3 layers of rectangular, thick-walled cells, 100-110 μm thick at the basal portion. Mid and apical portions composed of 2 layers of rectangular thin-walled cells (85-90 μm and 60-70 μm thick, respectively). Hairs develop in concentric bands on the upper surface of the thallus at intervals of 1.0-3.5 mm. Tetrasporangial sori in bands alternate with hair bands. Tetrasporangia to 120 mm diam. Antheridia (25×31 mm) in patches develop on the ventral surface of the thallus. Attachment by disc-like stupose holdfast. Prostrate rhizomes are often produced from the stipe (consisting of 4 cell layers). Rhizomes compressed, about 1 mm broad. Growing on mid intertidal to upper subtidal rocks and dead corals of shores with moderate wave action.

Tropics and subtropics of Atlantic, Indian and Pacific Oceans. Common in countries of the Asia-Pacific Region: Japan, China, Vietnam, Thailand, Indonesia, Philippines, Australia and New Zealand, Pacific Islands.