月芽铁线蕨 yue ya tie xian jue

Adiantum delavayi Christ; A. edentulum Christ; A. edentulum f. muticum (Ching) Y. X. Lin; A. edentulum f. refractum (Christ) Y. X. Lin; A. muticum Ching; A. subemarginatum Christ, p.p.; A. veneris Linnaeus var. sinuatum Christ.

Plants epilithic, 15-30(-50) cm tall. Rhizomes erect or ascending, short, scales dense, brown, lanceolate, margins entire. Fronds clustered; stipe castaneous-black, glossy, 5-17 cm, base covered with same scales as rhizome, distally smooth; lamina usually 2- or 3-pinnate, ovate or ovate-lanceolate in outline, 10-15 × 4.5-12 cm, base cuneate, apex acute; pinnae 4-6 each side, all parts obliquely ascending, stalked; rachises and stalks similar to stipe, zigzag, smooth; basal pair of pinnae largest, 1- or 2-pinnate, narrowly ovate or narrowly triangular-ovate in outline, 2.5-12 × 2-3 cm; pinnae from second pair upward all similar but progressively smaller; pinnules 4 or 5 pairs per pinna, alternate; stalk 0.5-4 mm, slender as silk; blade asymmetrical, flabellate, 5-15 × 8-14 mm, papery, abaxially gray-green, both surfaces glabrous, base shortly cuneate, bilateral sides entire, upper margin undulate-rounded, 1-4-lobate or semilobate (divided to middle), sterile pinnules entire or slightly undulate, fertile segments shallowly 2- or 4-lobed, terminal pinnules similar but slightly larger. Veins multidichotomously forked, reaching margins, visible on both surfaces. Sori 2-4(or 5) per pinnule, on lobe apices of upper margin; false indusia brown, narrowly reniform or orbicular-reniform, membranous, upper margins flat and straight or depressed, entire, persistent. Perispore reticulate.

● On rocks in forests, wet rocks covered with bryophytes in ditches, shaded wet cliffs, ditch sides of mixed forests; 1000-3600 m. Guizhou, Hubei, Hunan, Shaanxi, Sichuan, Xizang, Yunnan, Zhejiang.

Adiantum refractum is very similar to the Himalayan species A. wattii Baker and perhaps should be included within that species.