Polypodium undulatum Willdenow, Sp. Pl., ed. 4, 5: 155. 1810.

Plants terrestrial or epilithic; rhizome long creeping, growth monopodial, 4-5 mm in diam., not white waxy; roots restricted to ventral side, branched and hairy throughout their length; scales dark brown at middle, apex and margin red-brown, spreading, narrowly ovate-lanceolate, ca. 6 × 1 mm, base rounded, margin ciliate, apex acuminate. Fronds erect, scattered or in tufts; stipe and phyllopodia together 10-15(-20) cm, stramineous, phyllopodia to 2-12 cm; lamina brown when dry, lanceolate or broadly lanceolate, 15-25 × 2-4.5 cm, thickly papery, abaxially with long hairs, adaxially glabrous, base cuneate, rarely more gradually narrowed, to broadly cuneate or rounded, apex acuminate, margin slightly undulate and glabrous; costa raised on both sides, narrowly grooved adaxially; veins simple or forked at base, rarely forked medially. Sori to 2-5 mm from costa; indusia pubescent.

Sunny slopes; below 1000 m. Yunnan [India, Laos, Myanmar, Thailand, Vietnam].