A var.thibeticadiffert foliis 4–6.5 mm latis, spicis staminatis 1.5–2 mm latis, utriculis longioribus 9–12 mm longis.

China. Hunan: Dongan, Shunhuangshan Forestry Park, Butterfly Valley, by stream under forest, alt. 680 m, 21 May 2017, H. Wang 1434 (holotype: ZM; isotypes: ZJFC, ZM).

Rhizomes short or elongate, woody, stiff, with many brown fibrous roots. Culms lateral, loosely caespitose, 20–55 cm tall, obtusely trigonous, smooth, glabrous. Leaves basal, slightly shorter to longer than culms; blades flat, 4–6.5 mm wide, coriaceous, apex acuminate, lower surfaces and margin slightly scabrous. Bracts shortly leaf-like, shorter than spikes, sheathed; sheaths 1.5–2.5 cm long. Spikes 3 or 4 in a racemose; terminal spike staminate, narrowly linear-cylindrical, 3.5–8 cm long, 1.5–2 mm wide, base with 4–8 cm long peduncles; lateral spikes androgynous, staminate part longer than pistillate part, cylindrical, 4–9 cm long, 7–10 mm wide, 8–20-flowered (pistillate), with peduncles exserted from sheaths. Staminate glumes lanceolate or lanceolate-oblong, pale yellow-green, 7–7.5 mm long, apex acuminate, with pale brown 1-veined costa. Pistillate glumes narrowly ovate, pale green-brown or brown, 8.5–11 mm long, apex acuminate, with green or brown-green 3-veined costa. Utricles yellow-brown or brown, rhombic-ovoid, obtusely trigonous, 9–12 mm long, slightly longer than pistillate glumes, nearly erect or obliquely patent, distinctly thinly veined, sparsely puberulent on upper part, apex abruptly contracted into a 4.5–6 mm long beak, orifice 2-lobed with long teeth, margin barbate. Nutlets tightly enveloped, brown, rhombic-ovoid, trigonous, 3–4 mm long, base with a ca. 0.5 mm long curved stipe, apex abruptly contracted into a coiled short beak, with 3 angles constricted at middle and sides concave above and below; style base slightly thickened; stigmas 3.

The variety epithet ‘angustifolia’ refers to the narrower leaves (4–6.5 mm wide) than the typical variety (6–17 mm wide).

Flowering and fruiting is from mid-April to late May.

China. Hunan: Dongan, Shunhuangshan Forestry Park, Butterfly Valley, by stream under forest, alt. 680 m, 21 May 2017, H. Wang 1433 (ZJFC, ZM); the same locality, alt. 730 m, 19 Apr 2018, W.J. Chen 2394 (HTC, ZM), 2395 (ZJFC, ZM), 2396 (ZJFC, ZM). Suining, Huangsang Natural Reserve, Quyougu, under forest, alt. 755 m, 26 Apr 2014, J.J. Zhou & Z.P. Song 1404223 (CSFI); the same locality, Banchong, under forest, alt. 906 m, 2 May 2014, J.J. Zhou & Z.P. Song 1405022 (CSFI).

Least Concern (LC). The new variety is known from four localities in southern Hunan Province, but two of them are seriously disturbed by local people (IUCN 2019).

The new variety differs from the typical variety in having the leaves narrower, 4–6.5 mm in width, terminal staminate spikes 1.5–2 mm in width and utricles longer, 9–12 mm long. It differs from Carexthibaticavar.pauciflora in having lateral spikes with densely 8–20 pistillate flowers and utricles longer, 9–12 mm long.