C. nigerrima Nelmes in Kew Bull.: 200. 1939; C. atrata L. subsp. pullata (Boott) Kük. in Engler, Pflanzenr. IV.20, 38: 400. 1909; C. atrata L. var. pullata Boott, l.c. 3: 114. 1862.

Caespitose perennial, 40-60 cm. Rhizome short, horizontal. Stem sharply trigonous, smooth or slightly scabrous above, papillose. Leaves shorter than stem; sheaths 40-100 mm, reddish brown, strongly nerved, glossy, scarious side brown-spotted, margin concave; ligule to 0.7 mm, white with brownish spots, arch higher than wide; blades 2.5-3.5 mm wide, flat, keeled, margins revolute, both sides papillose, margins and keel scabrous. Inflorescence of 3-4(-5) spikes. Bracts equalling or overtopping inflorescence, with sheath to 5 mm. Terminal spikes to 24 mm, club-shaped, gynecandrous; other spikes 15-22 x 5-6 mm, ellipsoid or cylindrical, female or gynecandrous, peduncle to 45 mm; female glumes 3.9-4.3 x 1.5-2 mm, ovate, acute, dark reddish brown, papillose; utricles 4-4.2 x c. 1.9 mm, elongate ellipsoid, yellowish or golden-brown, with reddish brown spots, glossy, papillose, beak 0.1-0.2 mm, cylindrical, truncate, dark reddish brown. Stigmas 3. Nut c. 2.3 x 1.3 mm, including 0.4 mm persistent style base and a 0.1 mm stipe, widely obovoid, trigonous, light brown, reticulate with papilla in each areole.

Fl. Per.: July–August.

Syntypes: India, Gurwhal, 13-14000 ft., Duthie 4499; Sikkim, 11-15000 ft, J.D.Hooker s.n. (K).

High mountain meadows, 2800-5000 m; Distribution: From N Pakistan to Sikkim and Central China.

Description above is based primarily on the type specimen of C. nigerrima. C. duthiei is also closely related to C. perfusca V. Krecz., differing in having acute, papillose female glumes as long as or longer than utricles, without scarious margins. The constancy of these characters could not be verified as I have seen very little material. However, it should be noted that C. perfusca has been variously treated in relation to C. atrata L. (Kukkonen in Rech.f., l.c. 277. 1998).