Gelidocalamus albozonatus W.G.Zhang, S.R.Yi & Y.L.Li, 2023

Li, Yong-Long, Guo, Rong, Zhang, Hong-Jing, Yi, Si-Rong, Yang, Guang-Yao & Zhang, Wen-Gen, 2023, Gelidocalamus albozonatus (Poaceae, Bambusoideae), a new species from the southeast of Chongqing, China, and analysis of the morphological diversity in the core group of Gelidocalamus, PhytoKeys 236, pp. 17-27 : 17

Gelidocalamus albozonatus W.G.Zhang, S.R.Yi & Y.L.Li sp. nov.

Figs 1 , 2

Type.

China, Chongqing, Pengshui County, Luduhu Village , under the forest, 29°18′55.38″N, 108°13′42.14″E, elev. ca. 268 m, 6 Mar. 2019, S.R. Yi et al. CQPS01 (holotype: JXAU!) .

Diagnosis.

G. albozonatus is similar to G. tessellatus , but differed by having a ring of white (vs. brownish) tomenta below each culm node, culm sheath base densely purple setulose (vs. yellowish pubescence) and foliage leaf blades mesophyll (vs. notophyll).

Description.

Rhizomes leptomorph. Culms up to 5.5 m tall, ca. 6-15 mm in diam., erect, apically slightly nodding; internodes glabrous, 11-54 cm long, wall 1.5-3 mm thick; a ring of white tomenta below each node. Branching intravaginal, arising from the 6th node above ground, ca. 5-10 branches per node; branches equal or subequal, ca. 25-55 cm long, 2-4 mm in diam. Culm leaf sheaths tardily deciduous, 15-25 cm long, abaxially sparsely wine-red or purple hispidulous when young, purple patches densely distributed between transverse veins, sheath base densely purple setulose, ca. 1-3 mm long, margins with wine-red cilia, ca. 1-2 mm long; auricles absent or tiny; oral setae erect or slightly curved, 2-4 pairs, ca. 3-8 mm long; ligule less than 1 mm or absent; blade deciduous, linear or linear-lanceolate, 2-4.5 × 1.7-2.6 mm, erect or recurved, apex acuminate, base constricted with densely short setae, 1/3-1/2 as wide as sheath apex. Ultimate branches usually with one foliage leaf; branch sheath fragile; ligule absent or weak; auricles absent or tiny; blade broadly lanceolate to narrowly oblong, usually 19-42 × 4-7 cm, secondary veins 7-9 pairs, basally cuneate and asymmetrical, abaxially hairless, margins serrulate.

Distribution and habitat.

G. albozonatus occurs under evergreen broad-leaved forests, along the ravine to the east of Luduhu Village, at elev. ca. 200-600 m. It grows together with Cupressus funebris Endl. ( Cupressaceae ), Bambusa emeiensis L. C. Chia & H. L. Fung ( Poaceae ), and Nymphanthus calcicola S. R. Yi & Gang Yao, 2022 ( Phyllanthaceae ), and so on. So far, G. albozonatus is only known from one small population (lessthan 1000 m2) in the Pengshui County of Chongqing, China.

Chinese vernacular name.

péng-shuǐ-duǎn-zhī-zhú (彭水短枝竹).

Phenology.

New shoots Sep-Nov, Inflorescence unknown.

Etymology.

The specific epithet indicates the ring of white tomenta below the node.

Leaf micromorphology.

Stomatal apparatuses are embossed outwards and smooth without appendages, ca. 27 (25-30) × 13 (11-14) µm. The short papillaes are scattered on the leaf vein and stomatal zone. The exposed stomatal apparatus is surrounded by 8-10 short papillae, but not covered with wax. There are two types of trichomes (i.e., microhairs and prickles) on the abaxial leaf epidermis, but both are sparsely distributed on the abaxial leaf epidermis. The saddle-shaped silica bodies are clearly distributed on the veins. Microhairs are composed of two cells with the apical cell withered, and only occur on the intercostal regions of the abaxial leaf epidermis.

Conservation status.

Based on the field investigations in Pengshui County and adjacent regions (e.g., Shizhu, Qianjiang and Youyang). As the type locality is a mountain with steep terrain, only a population is found on the hillside on both sides of a valley. Therefore, before carrying out further investigations, this species should be assessed as "Data Deficient" (DD), according to the IUCN standards (IUCN 2022).

Figures

Figure 1. Gelidocalamus albozonatus sp. nov. A habitat B individual C rhizome D branches E culm node of new shoots F transection of culm and pith-cavity G dry new shoot H-L culms and culm leaves M foliage leaf blade. Scale bars: 1 m (A); 10 cm (B); 1 cm (C-E, G-L); 5 mm (F); 5 cm (M).

Figure 2. Illustration of Gelidocalamus albozonatus A culm and culm sheath B new shoot C details of culm sheath D culm leaf E oral setae details of culm leaf F-G branches and foliage leaves H details of foliage leaf sheath. Drawn by Rong Guo.