Carex xueyingiana H. J. Yang & Han Xu, 2017

Yang, Haijun, Xu, Han, Deng, Yunfei & Li, Yide, 2017, Carex xueyingiana (Cyperaceae), a new species from Hainan Island, China, Phytotaxa 308 (2), pp. 239-248 : 246

Carex xueyingiana H. J. Yang & Han Xu , sp. nov. ( Figs. 3 , 4 ) ǞḂAEạ

Diagnosis: —The new species is similar to C. chlorocephalula , but it differs from it by 1-leaves much longer than culms vs equaling these, densely long-pubescent on both sides vs hispidulous; 2-involucral bracts sheath-like, 5–6 mm long vs leaf-like and 8–10 cm long; 3- inflorescence with 1–2 dense spikes vs 2–3 laxer spikes; 4-spikes 7–10 mm long vs 10 –15 mm; and 5-perigynium apex beakless vs shortly beaked.

Type: — CHINA. Hainan: Ledong County, Jianfengling Nature Reserve , 920 m, 18°46’56.0”N, 108°59’42.7”E, 13 April 2012, Han Xu JFL001525 (holotype, IBSC; isotype, CANT) .

Perennial herb, 20–30 cm tall; rhizomes long. Culms loosely tufted, 6–12 cm tall, 0.3–0.8 mm thick, lateral, ascending to erect, trigonous, with up to three closed sheaths at base. Leaves basal, significantly longer than culms, 25–40 cm long, 4–6 mm wide, papery, flat, comprising a linear blade and an short sheath, densely long pubescent on both sides. Some fibrous sheaths persistent at the base of shoots. Inflorescence racemose, comprising 1–2 spikes. Bracts sheath-like, sometimes with a very short setaceous blade, 5–6 mm long, much shorter than inflorescence, adaxially glabrous, abaxially pubescent. Spikes 1–2, androgynous, 7–10 × 2–2.5 mm, oblong, the male part shorter or equaling the female part, both densely flowered; male part cylindric, 3–5 × 1–1.5 mm; female part obovate-lanceolate, 4–5 × 2–2.5 mm. Staminate scales broadly ovate, 2–2.3 × 1.2–1.6 mm, pale yellowish green, glabrous, blunt at apex. Stamens 3, 1 mm long; the anther remarkably longer than the filament. Pistillate scales 3.5–3.8 × 3–3.2 mm including awn, triangular-ovate, green, abaxially pubescent, 3-veined, the middle-nerve extending at apex into a 1mm long awn. Style hairy, thickened at base, stigmas 2 or 3. Perigynium 2.3–2.5 × 1.2–1.5 mm, broadly elliptic, compressed-trigonous, membranous, shorter than the pistillate scales, beakless, the orifice obliquely truncate. Ovary 0.7–0.8 × 0.3–0.4 mm, elliptic, glabrous, ripe achenes not known.

Distribution and habitat:—The species has been found so far in Jianfengling National Nature Reserve on Hainan Island, China. It grows in tropical monsoon rainforest at an elevation of about 920 m. Accompanying species include trees of Cryptocarya chinensis ( Lauraceae ), Alseodaphne hainanensis ( Lauraceae ), Lithocarpus fenzelianus ( Fagaceae ), Prismatomeris tetrandra ( Rubiaceae ), Livistona saribus (Palmae) ( Zeng et al. 1995) . In recent years, several new species have been found from Jianfengling Natural Reserve ( Xu et al. 2011, Xu et al. 2012, Yang et al. 2015a). The finding of C. xueyingiana remarks the need of additional taxonomic studies for a better understanding of the diversity of Hainan Island.

Phenology:—It flowers in the period from middle spring to early summer between March and May.

Etymology:—The species is named in honor of Professor Xueying Zhuang (1961–2016), botanist at South China Agricultural University. She contributed greatly to the botanical research in South China.

Conservation status:—Since 1993, logging has been prohibited and the habitats have been protected within the nature reserve. Base on the current field survey, only one population with about ten individuals was found. Taking into account the ability to reproduce of Carex , more populations may be found in the future. Therefore, the new species can be assigned as Vulnerable (VU DD) according to IUCN Red List criteria ( IUCN, 2010), indicating a population data deficient when there is inadequate information to make a direct, or indirect, assessment of its risk of extinction based on its distribution and/or population status.

Figures

FIGURE 3. Carex xueyingiana. A. Habit of a living flowering plant; B. Inflorescence with two androgynous spikes; C. Female flower inside perigynium; D. Male flower and scale.

FIGURE 4. Carex xueyingiana. A. Flowering plant; B. Female part of spike; C. Pistillate scale, abaxial view; D. Pistillate scale, adaxial view; E. Leave, adaxial surface; F–G. Leave, abaxial surface; H. Male flower; I. Involucral bract; J. Pistil; K. Perigynium with pistil inside; L. Apex of perigynium.