海南穴子蕨 hai nan xue zi jue

Polypodium barathrophyllum Baker, J. Bot. 29: 107. 1891.

Stipe very short or fronds subsessile, up to 1 cm, moderately covered with hairs; hairs simple, solitary, dark reddish brown, up to 0.8 mm. Lamina linear-elliptic, 12-35 × 1.6-3 cm, gradually narrowing toward both ends, pinnately divided to wing 2-3 mm wide along rachis; pinnae inclined or widely ascending, oblong-lanceolate to oblong-triangular, entire, sometimes slightly undulate, acute or bluntly obtuse at apex, basal ones gradually shortened to form a broad wavy wing almost to base; middle pinnae largest, up to 15 × 5 mm; rachis prominent on abaxial side, slightly prominent to grooved on adaxial side, medium brown or darker; costae indistinct; veins hidden, but visible with transmitted light, simple; hairs simple, solitary, seldom tufted, seldom forked, dark reddish brown, sparse to frequent on margin and abaxial surface, occasional to sparse or absent on adaxial surface. Sori up to 8 pairs per pinna, orbicular to oval, medial or slightly closer to margin, sunk in cavities without prominent edges, rim of cavity without hairs.

Dense evergreen forests; 1000-1500 m. Hainan [Borneo, Cambodia, Indonesia, Malaysia, Philippines, Thailand, Vietnam].

Specimens in Chinese herbaria identified as Prosaptia khasyana (Hooker) C. Christensen & Tardieu are P. barathrophylla or P. intermedia. Prosaptia khasyana does not occur in China.