4. Prosaptia intermedia (Ching) Tagawa, J. Jap. Bot. 25: 115. 1950.
中间穴子蕨 zhong jian xue zi jue
Polypodium urceolare Hayata var. intermedium Ching, Bull. Dept. Biol. Sun Yatsen Univ. 6: 32. 1933; Prosaptia urceolaris (Hayata) Copeland var. intermedia (Ching) Ching.
Stipe very short, ca. 0.2 cm, with hairs dense, simple, solitary, medium to dark reddish brown, very short, ca. 0.1 mm. Lamina deeply pinnately divided to wing 0.5-1.3 mm wide along rachis, narrowly elliptic, 11-18 × 1.5-2.1 cm, base long attenuate, apex bluntly acute to acute; pinnae ascending; middle pinnae largest, narrowly triangular-oblong to narrowly oblong, 7-14 × 2-3 mm, sessile to slightly surcurrent above, decurrent below at base, entire or slightly crenulate in soral area, bluntly acute to acute at apex; rachis concolorous with lamina; costae slightly prominent and concolorous with lamina on both surfaces; veins hidden, simple; hairs simple and 1-3-forked, solitary, medium reddish brown, sparse to scattered on abaxial side of rachis, dense on adaxial side, occasional to sparse on margin and abaxial side of costae, sparse to scattered on adaxial side of costae, scattered to frequent abaxially on lamina in soral area, sometimes only on rim of soral cavities. Sori ± circular to broadly elliptic, deeply sunken in cavities in lamina with rim 0.2-0.6 mm high, higher on side nearest costa, slightly prominent on adaxial surface, 2-5 in a medial row on each side of costa.
On moss-covered tree trunks in dense mountain forests; 700-1800 m. Guangdong, Guangxi, Hainan, Yunnan [Vietnam].