Haec species C. perakensi C.B. Clarke affinis est, sed squamis staminatis et pistillatis fulvis, utriculis 9–10 mm longis, glabris, rostris margine serrulatis, stylis basi glabris differt.

China. Guangxi: Huanjiang, Dongxing Town, Jiupengtun, by stream, alt. 1200 m, 22 May 1989, Beijing Exped 894059 (holotype: PE).

Rhizomes dark brown, woody, stiff, sometimes stoloniferous, with black-brown fibrous roots. Culms central, loosely caespitose, 40–80 cm tall, trigonous. Leaves basal and cauline; basal leaves longer than or almost equal to culms, blades 5–12 mm wide, coriaceous, apex acuminate, margin scabrous; cauline leaves 1 or 2, sometimes absent, slightly longer than inflorescence, blades 5–9 mm wide, coriaceous, apex acuminate, margin scabrous. Bracts leaf-like, longer than or slightly longer than inflorescence, 2.5–8 mm wide, with the lowest sheath to 2 cm long, upper sheaths shorter or sheath absent. Panicle compound, 15–28 cm long, 2 inflorescence branches in each bract sheath, rarely single; inflorescence branch 5–8.5 cm long, base pedunculate; bractlets scale-like, broadly ovate-round, yellow-brown, 4–5 mm long, ca. 4.5 mm wide, apex obtuse or mucronate, with yellow 1-veined costa. Spikes 13–46, sessile, 4–7 in a racemose; terminal spikes narrowly ovate or ovate-elliptic, 13–17 mm long, 6–7 mm wide, base with 3–6 pistillate flowers, staminate part 6–8 mm long; lateral spikes elliptic-lanceolate, 7–12 mm long, 2–3.5 mm wide, base with single pistillate flower, staminate part 5–8 mm long. Staminate glumes narrowly obovate or obovate-elliptic, yellow-brown, 6.5–7 mm long, apex acuminate or obtuse, with yellow 1-veined costa. Pistillate glumes broadly ovate, yellow-brown, 6.5–7 mm long, apex obtuse, with yellow 1-veined costa excurrent into a 0.5–1 mm long scabrous awn. Utricles pale brown, obovoid, compressed trigonous, 9–10 mm long, obliquely patent, glabrous, abaxially, and adaxially with 9 or 10 veins, respectively, apex gradually contracted into a 3–3.5 mm long erect beak, orifice obliquely truncate, margin barbate. Nutlets loosely enveloped, grey-brown, narrowly ovoid, trigonous, ca. 3.5 mm long, base with ca. 0.7 mm long stipe; style base curved, not thickened; stigmas 3.

The specific epithet ‘huanjiangensis’ refers to the type locality of this new species, Huanjiang County of Guangxi Zhuang Autonomous Region.

Flowering and fruiting is in early to late May.

China. Guangxi: Huanjiang, Jiuren Forestry Farm, on slope under forest, alt. 1450 m, 21 May 1989, Beijing Exped. 892928 (PE); the same locality, alt. 980 m, 21 May 1989, Beijing Exped. 893056 (PE); on slope under forest, alt. 1000 m, 25 May 1989, Beijing Exped. 895076 (PE); by stream, alt. 700 m, 25 May 1989, Beijing Exped. 895011 (PE); Rongshui, Xiangcaopeng, by stream, alt. 1000 m, 2 May 1989, Beijing Exped. 892115 (PE).

Least Concern (LC). The new species grows on slopes under the forests in Huangjiang and Rongshui Counties, where are seriously disturbed by local people (IUCN 2019).

Based on phylogenetic analyses, the large Decora clade includes most species in sections Decorae and Indicae (Roalson et al. 2021). Herein, we identified the former section as lacking utriculiform cladoprophylls, whereas they are present in section Indicae. This new species is similar to Carexperakensis, but differs in having both staminate and pistillate glumes yellow-brown, utricles longer (9–10 mm long), glabrous, with beak margins barbate and styles glabrous. In Carexperakensis, the glumes are pale yellow-brown, the utricles are 4.5–6 mm long, densely hispidulous and styles are sparsely barbate.