﻿Silenevanchingshanensis (Caryophyllaceae) a new species from Southwest China

﻿Abstract Silenevanchingshanensis (Caryophyllaceae), a new species from Fanjingshan Mountain in Guizhou (southwest China) is described and illustrated. It is morphologically similar to S.morrisonmontana and S.hupehensis, from which it can be easily distinguished by having pubescent stems usually 10–15 cm long, linear-oblanceolate leaves 3–6 cm × 3–6 mm, often 2–5-flowered cymes, pink or violet petals and narrowly ovoid capsules.


Introduction
Silene L. (Sileneae DC., Caryophylloideae Arnott, Caryophyllaceae Juss.) is the largest genus of the carnation family, comprising 700 to 870 species (Mabberley 2017;Jafari et al. 2020), mostly occurring in temperate regions and subtropical mountains of the Northern Hemisphere (Zhou et al. 2001;Oxelman et al. 2011). The centre of its species diversity is observed in Western Asia and the Mediterranean area, but areas of Central Asia are also highly diverse (see, for example, Jafari et al. 2020). Taxonomically, Silene represents a notoriously difficult genus, having a high species-richness, widespread distribution, broad morphological variations and the complex genetic background. Its generic delimitation has been controversial (Oxelman and Lidén 1995;Jafari et al. 2020) with some authors lumping many members into the genus (e.g. Greuter 1995;Desfeux and Lejeune 1996;Jafari et al. 2020), whereas others support separation of Agrostemma, Atocion, Eudianthe, Heliosperma, Petrocoptis and Viscaria (e.g. Oxelman and Lidén 1995;Oxelman et al. 1997Oxelman et al. , 2001Popp and Oxelman 2004;Frajman et al. 2009a, b;Greenberg and Donoghue 2011). In addition to taxonomic research, the genus Silene is also difficult from the nomenclatural point as highlighted, for example, by Iamonico (2018Iamonico ( , 2021. Concerning China, the first comprehensive revision of the genus Silene was carried out by Tang (1996) who recognised 131 species (including two subspecies and 17 varieties). In the most recent treatment by Zhou et al. (2001), 110 species were accepted, of which 67 are endemic. Silene taxa can be found throughout the country, mostly being found in the north-western and south-western provinces, with more than 60 species in the Hengduan Mountains (Zhou 1983;Wu 1993;Zhuang 1995;Tang 1996;Wu et al. 2003).
As part of the taxonomic revision of Silene in the Sino-Himalayan Region for the Flora of Pan-Himalayas, an undescribed species was found and is proposed here.

Materials and methods
The new species was studied both in the field and at herbaria. The collections housed at CDBI, KUN, PE, PYU, XTBG and YUKU (acronyms according to Thiers 2022), as well as digital images available at JSTOR Global Plants (http://plants.jstor.org/) and at the Chinese Virtual Herbarium (http://www.cvh.ac.cn/), were examined. Pertinent taxonomic literature (e.g. Xiao and Xie 1982;Zhuang 1995;Tang 1996;Zhou et al. 2001) were extensively consulted. Morphological studies were carried out on dried material under a stereomicroscope (Olympus SZX2, Tokyo, Japan) and measurements were made using a ruler and a metric vernier caliper. Diagnosis. Silene vanchingshanensis is similar to S. morrisonmontana, from which it differs by its shape and size of leaves (linear-oblanceolate, 3-6 cm × 3-6 mm vs. linear, 2-7 cm × 2-3 mm), cymes (often 2-5-flowered vs. usually solitary) and colour of petals (pink or violet vs. white).
Phenology. Flowering and fruiting times from July to September. Etymology. The specific epithet vanchingshanensis is derived from the type locality "Vanchingshan", a variant name for Fanjingshan Mountain.
Distribution and habitat. Silene vanchingshanensis is currently known only from locus classicus (Fanjingshan Mountain), a famous scenic resort in Guizhou, southwest China. The species grows on cliffs or rock crevices of the mountain summit at elevations of 2,100-2,500 m.
Taxonomic notes. The name Silene vanchingshanensis was first proposed by the Chinese botanist Zhengyi Wu in 1988 on the label of a KUN specimen (C. P. Jian et al. 32080). However, no name was formally published.