杜氏粉背蕨 du shi fen bei jue

Cheilanthes duthiei Baker, Ann. Bot. (Oxford) 5: 210. 1891; Leptolepidium duthiei (Baker) X. C. Zhang & G. M. Zhang.

Rhizomes erect, short; scales concolorous, dark brown, broadly lanceolate. Fronds clustered. Stipe dark brown to black, 2.5-9 cm, grooved, scaly, at least a few scales extending to rachis; scales concolorous, dark brown to reddish brown, broadly lanceolate at stipe base, grading abruptly to narrowly ovate above base. Lamina oblong-deltoid to ovate-deltoid or subpentagonal, 5-7 × 3-5 cm, pinnate-bipinnatifid to pinnate-tripinnatifid, thinly herbaceous to membranous when dry, non-farinose abaxially but with short, brown to dark brown, capitate glands along costae, costules, and veins, glabrous adaxially; pinnae 4 or 5 pairs, distinct along rachis, basal pair of pinnae oblong-deltoid, ca. 1.5 × 1 cm, bipinnatifid to tripinnatifid; pinnules 3 or 4 pairs, proximal basiscopic ones largest, pinnatifid to pinnate; second and upper pairs of pinnae same shape as basal one, but slightly shorter and narrower. Veins pinnate, relatively conspicuous. Sori consisting of 2-4 sporangia, confluent at maturity. False indusia interrupted, margins irregularly crenate or dentate.

Rock crevices; 3500-4400 m. SW Sichuan, Xizang [Bhutan, India, Nepal].

Aleuritopteris duthiei is a relatively small-fronded species, readily distinguished from other species of the genus by its lamina not farinose or villous; the grooved stipes and rachises; and the distinctive, dense, short, brown to dark brown capitate glands on costae, costules, and veins abaxially. It is apparently a rare species, occasionally collected at high elevations in the Himalayan region.