Carex yankouensis X. L. Yu, A. Liu & J. J. Zhou 2025, sp. nov.

Carex yankouensis X. L. Yu, A. Liu & J. J. Zhou sp. nov. Figs 1, 2, 3 Diagnosis. This new species is similar to C. brevicuspis C. B. Clarke, but differs from it in having shorter culms (10–15 cm vs 20–55 cm) and spikes (1–1.5 cm vs 3.7–7 cm), leaves much wider (15–20 – 35 mm vs 5–10 mm) and lighter colored (pale green or yellow-green vs dark green), nutlet beak oblique (vs straight or slightly curved), and style base slightly thickened (vs conspicuously thickened) (Referring to Fig. 5, Table 1). Type. China • Guangdong: Qingyuan City, Yingde County, Jiulong Town, Yankou, in dry limestone, elevation ca. 100–200 m, 4 April 2022, Ang Liu LAYD 01 (Holotype CSFI!, isotype HIB!, CSH! & ZJFC!) (Referring to Fig. 4). Description. Perennial herbs. Rhizome short, stout. Culms 10–15 cm tall, blunt trigonous, smooth, base clothed with brown fibrous sheaths. Leaves up to 30 cm long and 15–20 (- 35) mm wide, longer than culms, blades papery, soft, broadly linear, pale green or yellow-green, flat, margin entire, apex acuminate or tailed, distinctly transverse veins between the leaf veins. Bracts leaflike, much shorter than inflorescence, sheathing. Spikes 4–5, distant, the proximal spike usually nearly basal and far from the distal ones; terminal spike staminate, 1–3 (- 4) cm, linear, with a peduncle ca. 3 cm; lateral spikes mostly pistillate, sometimes with several male flowers at apex, 1–1.5 × 0.6–0.8 cm, narrowly cylindric, densely flowered, the proximal-most one with a peduncle 3–5 cm, smooth. Glumes ca. 3 × 1 mm, staminate and pistillate ones similar in morphology, linear-lanceolate, pale, edges transparent, green 3 - veined costa ending at apex, the tip rounded. Utricles ca. 5 × 2 mm (including beak), longer than or nearly equaling glumes, obliquely patent, the body ovoid or obovoid, pale green, the walls herbaceous, the surface sparsely pubescent, many veined, contracted at both ends, the apex abruptly contracted into a ca. 3 mm long beak, orifice 2 - lobed with sharp teeth. Nutlets ca. 2 × 1.5 mm, black-purple, ovate, trigonous, with 3 angles constricted at middle, faces concave at base, the epidermic cells forming an ornamentation of irregular polygons, base curved stipitate, apex abruptly contracted into an oblique beak, beak ca. 1 mm, slightly annulate at orifice; style base slightly thickened; stigmas 3. Phenology. Flowers observed from November to December, fruits from March to April. Etymology. The epithet of this new species is derived from the type locality. ‘ Yankou’ is the locality name, which means the entrance of a karst cave in Chinese. Distribution and habitat. This new species is currently only found in the limestone landform areas of Jiulong Town, and usually grows on the walls of limestone. Additional specimens examined (Paratypes). China • Guangdong: Qingyuan City, Yingde County, Jiulong Town, Hui long Park, in dry limestone, elevation ca. 120 m, 9 November 2023, Ang Liu LAYD 06 (CSFI!). Conservation status. At present, we have only found two populations with a total of about 200 individuals in the limestone areas of Jiulong Town. However, there are vast limestone landforms near the type location, and there may be distribution of this new species in these areas. Of course, we need a broader and deeper investigation to confirm that. According to the IUCN red list criteria (IUCN 2024), the conservation status of the new species should be better categorized as ‘ Data Deficient (DD) ’.