29. Adiantum monochlamys D. C. Eaton, Proc. Amer. Acad. Arts. 4: 110. 1858.
单盖铁线蕨 dan gai tie xian jue
Adiantum monochlamys var. simozawai Masamune; A. veitchii Hance; A. venustum D. Don var. monochlamys (D. C. Eaton) Luerssen.
Plants ?terrestrial, 15-55 cm tall. Rhizomes long creeping, scales dense, castaneous-black, glossy, narrowly lanceolate, margins entire. Fronds close together or spaced; stipe castaneous-black or castaneous, glossy, 15-28 cm, base covered with same scales as rhizome, distally glabrous; lamina 2(or 3)-pinnate, narrowly ovate-triangular in outline, 15-30 × 3-10 cm, base broadly cuneate, apex acuminate and 1-pinnate; pinnae 6-8 each side, spreading obliquely upward, stalk 1-1.5 cm; rachises, costae, and stalks zigzag, same color as stipes, glabrous; basal pair of pinnae largest, 2-pinnate, triangular-ovate, 4-8 × 3-4.5 cm; secondary pinnae 2 or 3 pairs per pinna; pinnules 3-5 pairs per pinna, obliquely ascending; stalk castaneous, short, slender; blade obtriangular, 6-10 × 5-8 mm, progressively slightly smaller distally, herbaceous, abaxially grayish green, both surfaces glabrous, base cuneate, apex rounded-truncate; fertile pinnules deeply depressed at middle, both sides with sharp triangular teeth, bilateral margins straight and entire; terminal pinnules with longer stalks. Veins multidichotomously forked, reaching ends of teeth of pinnules, visible on both surfaces. Sori 1(or 2) per pinnule, in sinus of upper margin; false indusia dark red-brown, reniform, thinly papery, upper margin deeply sinuate, entire or slightly undulate, persistent. 2n = 116.
Forests on mountains, shaded rocks and cliffs in forests; 700-2500 m. Guizhou, Sichuan, Taiwan, Zhejiang [Japan, S Korea].
"Adiantum monochlamys var. plurisorum" (H. Léveillé, Bull. Acad. Int. Géogr. Bot. 20: 4. 1910) belongs here but is a nomen nudum and was not therefore validly published (Melbourne Code, Art. 38.1(a)).