Gelidocalamus xunwuensis W.G.Zhang & G.Y.Yang, 2017

Zhang, Wen-Gen, Ji, Xue-Nan, Liu, Yu-Guang, Li, Wei-Jian & Yang, Guang-Yao, 2017, Gelidocalamus xunwuensis (Poaceae, Bambusoideae), a new species from southeastern Jiangxi, China, PhytoKeys 85, pp. 59-67 : 62-65

Gelidocalamus xunwuensis W.G.Zhang & G.Y.Yang sp. nov. Figs 3 , 4

Diagnosis.

Similar to G. stellatus Wen (1982: 22) in the habit and branch, but differs by culms sparsely hairy (early period) with granuliferous warts (adult or later period), each node with a ring of fulvous appressed trichomes below, culm leaf sheath densely hispidulous with a blade broadly lanceolate and 3-5-paired oral setae, branch sheath glabrous, foliage leaves broadly lanceolate to narrowly oblong, and new shoots late October.

Type.

CHINA. Jiangxi Province: Xunwu County, 24°54'1.59"N, 115°28'2.78"E, elev. ca. 540 m, 7 Nov. 2015, W.G. Zhang et al. 1107 (holotype: JXAU!) (Fig. 3A ) .

Description.

Rhizomes leptomorph. Culms up to 2.5 m tall, ca. 2.0-5.6 mm in diam., erect, apically slightly nodding; internodes rough strigose with granuliferous warts, 12-20 cm long, wall 0.5-1.5 mm thick; each node with a ring of fulvous appressed hairs below and above sheath scar; nodal line upheaving markedly above 3-5 unequal buds, supranodal ridge present and prominent. Branching intravaginal from 4th node up, ca. 4-9 branches each node; branches equal or subequal, ca. 8-32 cm long, 1-2 mm in diam. Culm leaf sheaths tardily deciduous, 7-10 cm, abaxially carmine and densely hispidulous when young, then grey-white when old, ribbed-striate, pubescent with stiffly dark-brown hairs, apex slightly oblique and truncate; auricles absent or weak; oral setae curved, ca. 2-5 mm, 3-5-paired; ligule truncate, ca. 1 mm, scabrous, very shortly finely fimbriate; blade deciduous, narrowly triangular or linear-lanceolate, 10-15 × 0.9-1.2 mm, erect or recurved, apex acuminate, base blunt or truncate, ca. 1/3-1/2 as wide as sheath apex, margins scabrous. Ultimate branches usually with 1 foliage leaf; branch sheath glabrous; ligule truncate, ca. 1 mm, scabrous; auricles absent or weak; oral setae erect or curved; leaf blade narrowly oblong, ca. 15-20 × 2.3-3.0 cm, abaxially pubescent near base, apically acuminate, basally cuneate and symmetrical, margins serrulate and slightly revolute near base.

Etymology.

The species epithet xunwuensis refers to the locality of the type specimen: Xunwu County, Jiangxi, China.

Phenology.

New shoots late October; flowering unknown.

Distribution and habitat.

Gelidocalamus xunwuensis occurs under evergreen broad-leaved forests, along ravine, and roadsides at elev. ca. 400-600 m. It grows together with Castanopsis kawakamii Hay., Dicranopteris pedata (Houtt.) Nakaike, Gnetum parvifolium (Warb.) C. Y. Cheng & Chun, Eurya chinensis R. Br., Semiliquidambar cathayensis H. T. Chang, and Ormosia semicastrata Hance. Gelidocalamus xunwuensis is currently known from only one small populations (less than 100 culms) in the southern China.

Leaf micromorphology.

Stomatal apparatuses, ca. 22 (20-24) × 12 (10-14) µm, are embossed outwards and covered by platelet-like wax. Short papillae occur on the abaxial leaf epidermis and appear randomly around the stomata (ca. 6-10 short papillae). Microhairs are composed of two cells with the apical cell withered, mostly distributed on the intercostal regions of abaxial epidermis. Silica bodies are saddle-shaped on the veins and can be clearly identified (Fig. 2A ).

Conservation status.

As a running bamboo, the new species is difficult to count each individual. Using the World Conservation Union Red List Categories and Criteria ( IUCN 2012), G. xunwuensis should be treated as a data deficient species with less than 100 culms in the type locality.

Figures

Figure 2. SEM images of the abaxial leaf epidermis. A Xunwu plants (Xunwu, Jiangxi, China) B Gelidocalamus stellatus (Jinggang Mountain, Jiangxi, China). C Gelidocalamus tessellatus (Libo, Guizhou, China) D Gelidocalamus dongdingensis (Longyan, Fujian, China).

Figure 3. Gelidocalamus xunwuensis and Gelidocalamus stellatus. A G. xunwuensis, China, Jiangxi, Xunwu County, Guizhumao, W. G. Zhang et al. 1107 (holotype, JXAU!), with culm leaf sheath stiffly hairy and foliage leaf broadly lanceolate to narrowly oblong B G. stellatus, China, Jiangxi, Jinggangshan, Xiazhuang, W. G. Zhang & W. J. Li 1606 (JXAU!), with culm leaf sheath glabrous and foliage leaf lanceolate to narrowly lanceolate.

Figure 4. Gelidocalamus xunwuensis. A habitat plants B new shoot C-L detailed characters, show branch and branch sheath (C-D), transection of culm and pith-cavity (E), culm and its leaf sheath (F-J), buds (K) and foliage leaf (L). Scale bar: 5 cm (A-D, F, L), 5 mm (E, G-K).