台湾穴子蕨 tai wan xue zi jue

Polypodium urceolare Hayata, Icon. Pl. Formosan. 5: 324. 1915.

Stipe 1-2 cm, with hairs scattered, simple, medium to dark reddish brown, up to 1.5 mm. Lamina linear-elliptic, 5-25 × 0.8-2.5 cm, gradually attenuate toward base, pinnately divided to wing 1-2 mm wide along rachis, apex acute to acuminate; pinnae approximate, subspreading, narrowly oblong, slightly dilated at base, entire in sterile pinnae, crenate-undulate toward apex on margin in fertile ones, obtuse or rounded at apex, sometimes rounded-truncate; middle pinnae largest, 6-15 × 2-3 mm; lower several pairs of pinnae gradually shortened, remote, abbreviate, deltoid or rounded; rachis slightly prominent on both sides, medium brown or darker; costa indistinct; veins quite hidden, simple, invisible even with transmitted light; hairs simple, solitary or rarely tufted, or rarely 1-forked, medium to dark reddish brown, scattered on both sides of rachis, sparse on margin and abaxial surface of lamina, occasional on adaxial surface. Sori deeply sunken in submarginal urceolate cavities opening obliquely outward, 2-5 on each side of pinna, rim of cavity prominent at least on basal side, with hairs along rim (sometimes lost in old fronds).

On moss-covered tree trunks in dense mountain forests, also on moss-covered rocks; 600-2200 m. Taiwan [Philippines].