Two new species of Oreocharis (Gesneriaceae) from karst regions in Yunnan and notes on O. tetraptera and O. brachypoda from China

Abstract Two new species of Gesneriaceae, Oreocharis aimodisca and O. longipedicellata, from the limestone area of Yunnan Province, China, are described and illustrated. Their morphological relationship with similar species is discussed and colour photographs, detailed descriptions, distribution and habitat, as well as the IUCN endangered status are provided. We also discuss the accuracy of the scientific names of the described species O. tetrapterus from Guangxi, China in 2019 and O. brachypodus from Guizhou, China, in 2015, and put forward corrections related to name form.


Introduction
At least 30 new taxa of Oreocharis Benth. (Gesneriaceae) have been described and officially published (e.g., Cai et al. 2017Cai et al. , 2019Do et al. 2017;Chen et al. 2018;Guo et al. 2018;Möller et al. 2018;Pan et al. 2019;Yang et al. 2019) after the generic redefinition based on new evidence following the development of molecular phylogenetics in 2011 (Möller et al. 2011) and several later adjustments of the species (Middleton et al. 2013;Chen et al. 2014;Möller et al. 2014;Möller 2015). Oreocharis s.l. hitherto comprises more than 140 taxa, mainly distributed in South and Southwest China (Wen et al. 2014) and a few species extending into North Vietnam (nine species), Myanmar (two species), Bhutan (one species), India (one species), Japan (one species) and Thailand (one species) (Xuyen et al. 2016;Do et al. 2017;Möller et al. 2017Möller et al. , 2018Chen et al. 2018). Li and Li (2015) and Pan et al. (2019) each described new species of Oreocharis. One of the taxa with four corolla lobes is from Guangxi, China, which they named O. tetrapterus F.Wen, B.Pan & T.V.Do . The other has sessile or shorter petiole leaves and four stamens with anthers coherent in pairs from Guizhou, China, which was named as O. brachypodus J.M. Li & Z.M. Li (Li and Li 2015). These scientific names are improperly formed because the Latin forms 'tetrapterous' and 'brachypodus' are masculine and the Latin word of this genus, 'Oreocharis', is feminine. We revise the Latin name to 'tetraptera' and 'brachypoda' here and provide appropriate notes.
In 2018, during field investigations in the limestone area in Southeast Yunnan, China, an unknown species of Gesneriaceae without flowers was collected, then was introduced to, and cultivated in, Guilin Botanical Garden (GBG). We first observed flowering plants which were cultivated in GBG in August 2019. Thereafter, in September 2019, another unknown species of Gesneriaceae with flowers was collected from Shizong County, eastern Yunnan. We confirmed that they are both members of Oreocharis, based on the characteristics of leaves in a basal rosette, four separated fertile stamens and capsules dehiscing predominantly on one side. After a careful examination of the related specimens and taxonomic publications of Oreocharis from the adjacent regions (Wang et al. 1990(Wang et al. , 1998Li and Wang 2005), we concluded that these two species are both new to science. Here, Oreocharis aimodisca and O. longipedicellata are described and illustrated and their morphological characters are compared to closely-related species.

Material and methods
Extensive fieldwork has been undertaken in the east and southeast of Yunnan, China, in recent years. Samples of the two new species were respectively collected from the fields of Shizong County and living plants cultivated in Guilin Botanical Garden (GBG) which initially introduced from Malipo County, Yunnan, China. All available specimens of Oreocharis s.l., stored in herbaria (E, HITBC, IBK, HN, K, KUN, P, PE and VMN), Chinese Virtual Herbarium (http://www.cvh.ac.cn/) in China and Global Plants on JSTOR (https://plants.jstor.org/) were examined. We studied all morphological characters with dissecting microscopes and described the morphological characters by using the terminology presented by Wang et al. (1990Wang et al. ( , 1998. The photographs and the specimens were taken in the field and GBG by the first and correspondence authors. All specimens seen are indicated by '!'. Notes. The gender of the genus name, Oreocharis, is feminine, but the suffix of the scientific name, "-us," is typically masculine. For Oreocharis tetrapterus , the correct orthography of the name of the new species is O. tetraptera, is written by using an inaccurate gender, namely "tetrapterus", in the citation of the type of the new species (p. 85), in the discussion of the Etymology (p. 86) and in the notes of the illustration (pp. 86, 87 and 88). In the other new taxon, Oreocharis brachypodus (Li and Li 2015), the correct orthography of the epithet "brachypoda" should be used to replace "brachypodus". The inaccurately-used name gender appeared in the citation of the type of the new species (p. 296) and in the notes of the illustration (pp. 297 and 298). Thus, here we correct and revise two new species' names as Oreocharis tetraptera and O. brachypoda. Weber in the appearance and colour of its flowers, but differs from the latter two species in its leaf blade oval to ovate, base cordate or auriculate, margin crenate, peduncle densely brown villous and pubescent, corolla outside densely pubescent and four separated fertile stamens, pistil densely pubescent and disc blood red.
Phenology. Flowering from August to September; fruiting from September to December.
Distribution and habitat. Oreocharis aimodisca is currently known from two adjacent populations at the type locality, Shizong County, East Yunnan, China. The new species commonly growing with other plants in shady and wet places on the middle part of mountain slopes under primary evergreen broad-leaf forest and shrubbery on karstic limestone at an elevation of over 2000 m. Etymology. The original specific epithet 'aimodisca' derives from the Greek 'αίμα' meaning blood red and 'δίσκος' meaning discus. Vernacular name. The Chinese name of the new species is "Diān Dōng Mǎ Líng Jù Tái" (滇东马铃苣苔). The first two words, "Diān Dōng," mean east of Yunnan, the next four words, "Mǎ Líng Jù Tái," mean Oreocharis in Mandarin.
Conservation status. Based on our field investigations, the new species is currently only known from the type locality with two contiguous subpopulations, in total ca. one thousand mature individuals were present within 5000 m 2 (AOO). Since no special surveys were carried out for delimiting its distribution and information about threats is not very clear, this species was provisionally considered to be Critically Endangered [CR B2(a)] in terms of the IUCN Red List Categories and Criteria (IUCN 2019).

Taxonomic affinities.
Oreocharis aimodisca is morphologically similar to O. longifolia and O. muscicola in the corolla yellow and coarsely tubular; however, it is different from the latter two species by the shape of the leaf blade, indumentum characters of the peduncle, pedicel, calyx, corolla and pistil and separated stamens. The comparison of morphological characters on related species is provided in Table 1. Diagnosis. Oreocharis longipedicellata morphologically resembles O. panzhouensis Lei Cai, Y.Guo & F.Wen in its ovate leaf blade, yellow flower, four separated fertile stamens, oblong anthers and bilobed, flabellate stigma, but can be easily distinguished from this species in the peduncle 20-28 cm long, bract lanceolate to elliptic, margin denticulate, the calyx 5-lobed to the base, stamens adnate to corolla 3-4 mm from base and the pistil 1.5-2 cm long.
Etymology. The specific epithet 'longipedicellata' refers to the relatively-long peduncle of the new species. This species has almost the longest pedicels in the genus Oreocharis. Vernacular name. The Chinese name of the new species is "Cháng Gěng Mǎ Líng Jù Tái" (长梗马铃苣苔). The first two words, "Cháng Gěng," mean the long peduncle. The next four words mean Oreocharis in mandarin.
Conservation status. The new species could be endangered, but more data is needed to evaluate as the field distribution information is not sufficiently detailed.
Taxonomic affinities. Oreocharis longipedicellata most resembles recently published O. panzhouensis in the yellow flower, four separated stamens, calyx 5-lobed to the middle and stigma bilobed, flabellate. Nevertheless, it differs from the latter species in several other characteristics (see Table 2).