Padina gymnospora

Thallus flabellate, with broadly rounded lobes, sometimes split into narrower fanshaped blades with inrolled outer margins. 4-8(-22) cm high, 5-9(-20) cm broad, Lightly calcified usually on the upper side, yellowish-brown, olive-brown. Вlades at growing marginal (inrolled) portion composed of 2 cell layers, 50-60 μm thick, below becoming 3 cell layers through the thallus (75-110 μm thick), 4 cell thick near the stipe and stipe composed of up to 9 cell layers. Hairs develop in concentric bands on both sides of the thallus. Tetrasporangial sori develop median between the alternate (dorsal and ventral) hair bands. Tetrasporangia oval, cruciately divided, to 15×35 mm. Attachment by single stypose holdfast.Growing on low intertidal to upper subtidal rocks and dead corals in sheltered and moderately exposed to wave action shores.

Worldwide, in tropical and subtropical waters of Atlantic, Indian and Pacific Oceans. Common in countries of the Asia-Pacific Region: Japan, China, Vietnam, Indonesia, Philippines, Australia and New Zealand.