Oreocharis polyneura , a new species of Gesneriaceae from southern Yunnan, China

Oreocharis polyneura , a new species from southern Yunnan, China, is described and illustrated. It is mor-phologically similar to O. rhytidophylla by having more obvious lateral veins forming a crosslinked network on the adaxial surface of leaf blades, but can be distinguished by having more lateral veins (12–15 pairs vs. 7–9 pairs) of leaf blades, shorter corolla tubes (the length ratio of corolla tube to corolla lobes = 1.2–2.9 vs. 3.4–6) and shorter pistils (6–8 mm long vs. 27–30 mm long). In addition, a detailed morphological description, a photographic illustration, the distribution and phenology of the new species are presented.


Introduction
In recent years, the genus Oreocharis Benth. has been a hotspot for the research of the family Gesneriaceae. The newly circumscribed genus Oreocharis is recently enlarged by incorporating ten other genera (Ancylostemon Craib, Bournea Oliv., Dayaoshania W.T.Wang, Deinocheilos W.T.Wang, Isometrum Craib, Opithandra B.L.Burtt, Paraisometrum W.T.Wang, Thamnocharis W.T.Wang, Tremacron Craib, Briggsia Craib s.str.) with high floral diversity (Möller et al. 2011;Weber et al. 2013), although Bournea was later reinstated as an independent genus (Chen et al. 2020a). Hitherto, Oreocharis s.l. contains ca. 150 taxa mainly distributed in southern and southwestern China (Wen et al. 2021), with a few of them (ca. 15 species) expanding to Bhutan, India, Japan, Myanmar, Thailand, and northern and central Vietnam (Möller et al. 2016(Möller et al. , 2017(Möller et al. , 2018Cai et al. 2020a;Le et al. 2022). In China, southern Yunnan is rich in species diversity of the genus, with about 38 species recorded in this area (Li and Wang 2004;Möller et al. 2011;Chen et al. 2012Chen et al. , 2013Chen et al. , 2020bTan et al. 2013Tan et al. , 2015Rossini and Freitas 2014;Cai et al. 2015. In 2021, during the expedition of the plant resources of tropical Yunnan in China, we collected an interesting plant of Gesneriaceae from Lancang county at anthesis (Figs 1, 2). Judging from the vegetative habit and floral characteristics, we considered it a member of Oreocharis. Upon careful comparisons of diagnostic morphological and anatomical features from the closely related species from China and adjacent regions, we determined that the plant is new to science and thus describe it herein. Its morphological characters are compared with the closely related species Oreocharis rhytidophylla C.Y. Wu ex H.W. Li (Li 1983;Zhang et al. 2019) (Fig. 3).

Materials and methods
Vouchers of the new species were collected from Lancang County, Yunnan Province, China. Photographs and phenology data were obtained during field expeditions. Morphological examinations and measurements of the new species were conducted on both living plants in the wild and herbarium specimens. All morphological characters are described according to the terminology presented by Wang et al. (1990Wang et al. ( , 1998. The preliminary conservation assessment for the new species was evaluated according to the guidelines of the IUCN Red List Categories and Criteria (IUCN 2019). Diagnosis. Oreocharis polyneura is similar to O. rhytidophylla in having more obvious lateral veins forming crosslinked network on the adaxial surface of leaf blades, but can be distinguished by having more lateral veins (12-15 pairs vs. 7-9 pairs) of leaf blades, shorter corolla tubes (the length ratio of corolla tube to corolla lobes = 1.2-2.9 vs. 3.4-6) and shorter pistils (6-8 mm long vs. 27-30 mm long).
Phenology. Flowering from July to October; fruiting from September to November.
Habitat and distribution. Endemic to Zhutang town, Lancang county, Puer city, Yunnan Province, China (Fig. 4). It grows on rocks or cliffs under evergreen broadleaved forests in ravines at elevations of 1900-2200 m.
Conservation status. Oreocharis polyneura is currently known only from its type locality. Based on our present knowledge and available data, its conservation status is assessed as "Data Deficient" (DD; IUCN 2019).     Stamen two pairs cohered at the anther tips, adnate to corolla tube 4-6 mm from base adaxial stamens cohered in pair, abaxial stamens free, adnate to corolla tube 8-9 mm from base Pistil 6.0-8.0 mm long; ovary 5.0-6.5 mm long 27-30 mm long; ovary 17-18 mm long Vernacular name. The Chinese name of the new species is "Duō Mài Mǎ Líng Jù Tái" (多脉马铃苣苔). The first two words, Duō Mài mean the numerous veins of the leaf blades, and the rest four words mean the genus Oreocharis in mandarin.
Notes. Morphologically, Oreocharis polyneura is most similar to O. rhytidophylla in its leaves and inflorescences but is readily distinguishable by an array of characters (see Table 1).