﻿Oreocharisguangwushanensis, a new species of Gesneriaceae from Sichuan Province, China

﻿Abstract A new species of Oreocharis, O.guangwushanensis from the Sichuan Province of south-western China, is described and illustrated here. This new species has a pink corolla that is different from other species of Oreocharis in southwest China and, although it is morphologically similar to O.ronganensis and O.reticuliflora, it has significant differences in the colour and shape of the corolla, the apex of the corolla limb, shape and indumentum of the filaments and a shorter pistil. A detailed description, colour photographs, distribution and habitat, as well as the IUCN conservation status, are also provided.

In July 2020, three authors (ZLL, HJM, ZRY), found this plant in Guangwushan Provincial Nature Reserve during their plant diversity survey. They found this species growing on a large boulder by the roadside, but with only a small number of individuals. On the same day, they found plants of this species in flower at the bottom of a cliff. This population had more individuals than the population on the boulder, with many individuals in flower and fruit, from which they collected specimens. After further investigation, they found that there were only two populations in the Guangwushan Reserve. The author (HX) has seen this plant before, but mistakenly thought it was Oreocharis farreri (Craib) Mich.Möller & A.Weber, based on its vegetative habit because it was not in flower.
After consulting some Gesneriaceae monographs (Li and Wang 2004;Wei et al. 2010) and comparing the species with other described congeners (Wang et al. 1990(Wang et al. , 1998Chen et al. 2016;Wei et al. 2016;Do et al. 2017;Li et al. 2017;Yang et al. 2017;Guo et al. 2018;Möller et al. 2018;Pan et al. 2019;Yang et al. 2019;Cai and Dao 2020;Chen et al. 2020;Qin et al. 2020) and specimens of Gesneriaceae deposited at IBSC, IBK, KUN, PE, US and VMN, we referenced the older specimen information and articles from other species. Then we confirmed that it is a new species.

Materials and methods
The measurements and morphological characteristics of the new species were taken from the type specimens processed by the authors. We examined Oreocharis specimens in IBSC, IBK, KUN, PE, US and VMN, to find species that are morphologically similar. We confirmed it to be an undiscovered species. The type specimens of the new species were deposited in IBK and AHU and living individuals were cultivated at the Gesneriad Conservation Center of China. All morphological characters were studied under a dissecting microscope and were described using the terminology used by Wang et al. (1998).

Taxonomic treatment
Oreocharis guangwushanensis Z.L.Li & Xin Hong, sp.nov. urn:lsid:ipni.org:names:77300515-1 Fig. 1, Table 1 Diagnosis. Oreocharis guangwushanensis morphologically resembles O. ronganensis and O. reticuliflora. The new species is vegetatively similar to O. ronganensis, but it differs from the latter in that the adaxial lip is 2-lobed to or above the middle (vs. lobed to near base), ovary with white pubescence (vs. glabrous), anthers in pairs (vs. anthers free), shorter tube (9-14 mm vs. 20 mm), shorter pistil (5 mm vs.12-15 mm) and filaments strongly twisted and bent at the top (vs. linear, straight). The new species resembles O. reticuliflora in habit, flower tube and the shape of the calyx, but differs by its pink limbs (vs. limbs with a network of violet stripes), filaments strongly twisted and bent at the top (vs. linear, straight), anthers in pairs (vs. anthers free), ovary with white pubescence (vs. glandular-pubescence) and shorter pistil (5 mm vs. 10-12 mm).
Distribution and habitat. The new species has so far been found only in the type locality, Guangwushan Provincial Nature Reserve, Sichuan province, China. In the nature reserve, the average temperature is 16.2 °C, while the average annual precipitation has been calculated as ca. 1200 mm. The forest where O. guangwushanensis occurs is a monsoon evergreen broad-leaved forest.
Preliminary conservation assessment. Currently, the new species has been observed only from the type locality. After two years of careful investigation, only two small populations of O. guangwushanensis have been found. They are less than 200 m apart. In total, ca. 200 mature individuals were present within 4 km 2 (AOO). One population of no more than 40 individuals was growing at a higher altitude of 1124 m on a boulder near a road; the other population on a limestone wall at lower altitude 988 m by a river, close to the scenic area of the Guangwushan Provincial Nature Reserve which attracts many visitors. The locations of both populations are easily accessible and frequently passed by tourists, and thus, the number of individuals is likely to be detrimentally affected. The natural habitat could be disturbed or changed by human activities such as road expansion and other building construction. Following the IUCN Red List Categories and Criteria (IUCN 2019), the new species is provisionally assessed as Critically Endangered [CR B2ab(iii)].