易变铁角蕨 yi bian tie jiao jue

Type: China. Yunnan: shaded rocks in forest of "San-tcha-ho," above "Mo-so-yn," 17 May 1887, Delavay s.n, sheet 1, plant 7 (lectotype, designated here, P!).

Plants 3-8 cm tall. Rhizome erect, short, scaly; scales dark brown to black, narrowly triangular, margins fimbriate. Fronds caespitose; stipe green, thin, threadlike, 0.5-1.5(-2.5) cm, subglabrous, adaxially shallowly sulcate; lamina narrowly triangular to linear, 2-6 × 0.7-1.2 cm, base slightly or not reduced, bipinnate, apex acute or truncate, usually flagelliform with terminal small bud; pinnae 6-13 pairs, alternate or subopposite, shortly stalked and only occasionally with a gemma in upper axil, ovate, 4-6 × 3-4 mm, pinnate; pinnules 1 or 2 pairs, usually simple, elliptic, 2-3 × 1-2 mm, base cuneate, margin entire, apex acute; pinnae near apex less divided. Veins simple, 1 per pinnule or segment, not reaching margin. Fronds thinly herbaceous, green to grayish green when dry; rachis green, subglabrous, adaxially sulcate. Sori 1 per segment or pinnule, subelliptic, 0.5-1 mm; indusia grayish green, subelliptic, membranous, entire, opening toward costa, persistent. Sporangia with 32 spores, perispore lophate (alate), average exospore length 44-48 µm.

In deep crevices of shaded (limestone) rocks; 2500-3500 m. Guizhou, Sichuan, Yunnan [Bhutan, Nepal].

Asplenium fugax is easily overlooked as it is a small species hidden in moss cushions under boulders. Plants are often identified or reported as A. capillipes (e.g., Itô in H. Hara, Fl. E. Himalaya, 486-489. 1966; Nakaike, Bull. Natl. Sci. Mus., Tokyo, B, 12: 37-54. 1986), but that taxon never has a flagelliform apex. Christ (Bull. Soc. Bot. France 52(Mém. 1): 1-69. 1905) cited two syntypes: one collection by Delavay and another by Farges, both kept in Paris (P). Delavay’s gathering is a mixture mounted on three separate sheets numbered 1, 2, and 3. Most plants fit Christ’s description and belong to A. fugax, but there is also a Woodsia specimen on sheet 2. Plant "7" on sheet 1 (bearing Delavay’s original label) is well pressed, the most fertile and best developed, and it is selected here as lectotype. The other syntype (Sichuan [Chongqing], Tchen-kéou-tin, 2000 m, August, Farges 657 [P!]) belongs to A. capillipes.