Lingua means a tongue or tonguelike.
Rhizome: long-creeping, wiry, 3 mm, with phylopodia, scales dense, red to yellow-brown, to 8 mm.
Frond: 30 cm high by 5 cm wide, evergreen, somewhat dimorphic, fertile fronds shorter, narrower, blade/stipe ratio: 1:1 more or less.
Stipe: straw-colored to brown, star-shaped hairs dense while young, falling soon; a few scales near the base, vascular bundles: .
Blade: simple, ovate, leathery, thick, glossy above, star-shaped hairs on both surfaces when young, becoming glabrous above early, below later.
Margins entire; veins appearing free above, but obscurely netted below, difficult to see even with a hand-lens.
Sori: round or oblong, ends of veins, becoming confluent, indusium: absent, sporangia: yellow to brown at maturity.
Habitat: on rocks or trees in low mountains.
Distribution: Japan, China, Vietnam.
Hardy to -20°C, USDA Zone 6, perhaps.
The felt comes from the stellate hairs/scales on the lower blade surface; in some forms this is sparse and deciduous. There are few simple, entire blades on this site.
Acrostichum lingua Thunb.
Polypodium lingua (Thunb.) Sw.
Niphobolus lingua (Thunb.) Spreng.
Polycampium lingua (Thunb.) C. Presl