Phyllostachys hirtivagina G. H. Lai var. glabrivagina G. H. Lai & J. J. Yue, 2022

Lai, Guang-Hui & Yue, Jin-Jun, 2022, New taxa of the genus Phyllostachys (Poaceae: Bambusoideae) from east China, Phytotaxa 576 (2), pp. 193-202 : 196-199

Phyllostachys hirtivagina G. H. Lai var. glabrivagina G. H. Lai & J. J. Yue , var. nov. (Figs. 3,4)

Type: CHINA. Zhejiang Province: Longyou County, Donghua Town, near Gongping Road , growing on a hill, elevation 73 m, 29°00’27.34’’N, 119°11’47.24’’E, 12 April 2015, G. H. Lai 15021 (holotype, AAUF!; isotypes, herbarium of Guangde Forestry Institute!) .

Diagnosis: — Phyllostachys hirtivagina var. glabrivagina is different from P. hirtivagina var. hirtivagina in having abaxially glabrous culm leaf sheaths and narrowly falcate culm leaf auricles. This new variety is somewhat silimar to P. microphylla Lai (2013a: 7) in the narrowly falcate culm leaf sheath auricles, but differs in having circular and non-ribbed internodes in the branchless part of culm, unmarked culm leaf sheath without milky-white stripes, and larger foliage leaf blades. A detailed comparison among these three taxa is provided in Table 2 .

Description:— Rhizomes monopodial, internodes with a few air canals in transverse section. Culms 1.2–2.6 m tall and 1–1.6 cm in diameter, straight and apically recurved, young ones dark green tinged purple, glabrous, pruinose; old ones green or yellow-green; nodes moderately prominent, supranodal ridge more prominent than sheath scar; internodes 18–26 cm long; intranodes 3–4 mm long; branches 2 at each node, subhorizontal in the lower nodes. Culm leaves shorter than internodes, sheaths thickly papery, green or dark yellow-green, purple-red or purplish toward margins of the upper part when fresh, without spots or stripes, pruinose, with obvious veins, abaxially and basally glabrous, margins white ciliate; auricles well developed, initially purple-red, later becoming pale purple-red tinged with green, narrowly falcate, margin fringed with crinkly setae initially tinged with purple later withered; ligules ca. 2 mm tall, initially green tinged with purple, apex slightly arcuate, margin erose and sparsely white ciliolate; blades narrowly triangular or lanceolate, green and tinged with purple toward base and apex, usually flat, sometimes weakly wavy, erect or slightly decumbent. Foliage leaves 2–4 per ultimate branchlet; sheath initially green tinged with purple, hispidulous toward apex; auricles not developed; oral setae 2–5, nearly straightly extended, slightly curved, sometimes absent; inner ligules weakly exserted, 1–1.5 mm long, pale purple-red, apex truncate and erose; blades linear-lanceolate, 6– 11× 0.9–1.6 cm, adaxially green or yellow-green, abaxially greenish or pale yellow-green and white puberulent toward base, finely serrulate on two sides, lateral nerves 4- or 5-paired, transverse veins obscure. Inflorescence unknown.

Distribution and habitat:— The new variety was only found from Donghua Town, Longyou County, Zhejiang Province, China. It occurs on a hill covering an area of about 0.8 ha. at elevations of 71–83 m, and also grows sporadically in the surrounding wilderness.

Local use: —Its shoots are edible.

Phenology: —Shoot developed in early April.

Etymology:— The varietal epithet “ glabrivagina ” refers to the glabrous culm leaf sheath of the new variety, which is different from the hairy one of the nominate variety.

Chinese name:—Ḯäḝṱẖ (pinyin: guâng tuò zào ké zhú).

Conservation status:— The new variety is only found in its type locality within a minimal distribution range (less than 55 km 2) with several populations. Its largest population has been seriously damaged by human activities in recent years, and the others were also harmed by the continuous drought in the summer of 2022. According to the IUCN Red List Categories and Criteria (vers. 3.1 2nd ed.), it is therefore assigned a preliminary status of “Endangered” ( EN B2 abc). Due to its current narrow geographical distribution and poor growth status, it is urgent to take strict measures to protect this variety .