Species nova est affinis C. diplodo Nelmes, a qua spicis terminalibus androgynis, squamis pistillatis ovatis, apice breviter et scabrose aristatis, utriculis glabris, nucibus apice erostris facile differt.

China. Sichuan: Kangding, Zhonggucun, Wachang, 30°15'16.72"N, 101°52'47.75"E, in grass along stream, alt. 3061 m, 1 Aug 2019, X.F. Jin, Y.F. Lu & X.H. Xiong 4518 (holotype: ZM; isotypes: ZJFC, ZM)

Rhizomes creeping, woody, stiff, with many brown fibrous roots. Culms central, loosely caespitose, 25–60 cm tall, acutely trigonous, smooth, glabrous, with single bract-like leaf near base. Leaves basal, far shorter than culms; blades less than 12 cm long, flat, 2.5–5.5 mm wide, coriaceous, apex acuminate, margin slightly scabrous. Lower bracts shortly leaf-like, longer than spikes, upper ones setaceous, shorter than spikes, all bracts sheathed; sheaths 0.5–2.5 cm long. Spikes 4 or 5 in a racemose, terminal spike androgynous, clavate-cylindrical, 1.5–3 cm long, 2–2.5 mm wide, base with 1–6 pistillate flowers and a 1–2.5 cm long peduncle, lateral spikes pistillate, sometimes with 3–6 staminate flowers at apex, cylindrical, 1–2.5 cm long, 5–5.5 mm wide, 8–24-flowered, lower 1 or 2 peduncles exserted from sheaths, upper ones enclosed. Staminate glumes obovate, yellow-brown, 4.5–5 mm long, apex acute, with yellow 1-veined costa excurrent into a mucro. Pistillate glumes ovate, yellow-brown, margin whitish hyaline, 4–4.3 mm long, apex acute or obtuse, with yellow 1-veined costa excurrent into a 0.5–1 mm scabrous awn. Utricles yellow-brown, ovoid, obtusely trigonous, 5–6 mm long, obliquely patent, abaxially thinly 11–14-veined, adaxially thinly 8- or 9-veined, glabrous, apex gradually contracted into a 2–2.5 mm long beak, orifice 2-lobed with short teeth, margin barbate or smooth. Nutlets tightly enveloped, yellow-brown, broadly ovoid, trigonous, 2.3–2.5 mm long, base with a stipe ca. 0.3 mm long; style base slightly thickened; stigmas 3.

The specific epithet ‘liangiana’ is in honour of Prof. Song-Yun Liang, who is a Chinese researcher on the taxonomy of Cyperaceae and Liliaceae.

Flowering and fruiting is from late June to early August.

China. Sichuan: Kangding, Zhonggucun, Wachang, 30°15'16.72"N, 101°52'47.75"E, in grass along stream, alt. 3061 m, 1 Aug 2019, X.F. Jin, Y.F. Lu & X.H. Xiong 4512 (ZJFC, ZM); the same locality, in grass, alt. 3370 m, 29 Jul 1963, W Sichuan Exped. (K.C. Kuan & W.T. Wang) 505 (PE). Gansu: Zhouqu, Wuping Dist., Shatan Forestry Farm, in wetland, alt. 2300 m, 26 Jun 1964, P.C. Kuo 5115 (WUK).

Vulnerable, VU B2aC1 (IUCN 2019). This new species is known from two localities, Kangding of Sichuan Province and Zhouqu of Gansu Province, the area of occupancy is less than 10000 km² and the estimated individuals are less than 5000 individuals in the two populations.

It is a remarkable species in sect. Rhomboidales with the terminal spikes androgynous and the nutlets not beaked at the apex. It is somewhat similar to Carexdiplodon in the shape of the utricles and nutlets, but the new species has culms that are loosely tufted with elongate rhizomes and the nutlets neither concave nor excavated on the faces, which differentiates it from the majority of species in sect. Rhomboidales (Jin and Zheng 2013; Jin et al. 2014). Further phylogenetic study is needed to establish its relationships.