Four new species of Oreocharis (Gesneriaceae) in Yunnan province, China

Abstract Four new species of Oreocharis (Gesneriaceae) are described and illustrated. These new species grow in pairs in montane forests in Yunnan province, China. One pair grows in Wenshan county, Southeast Yunnan, viz. Oreocharis eriocarpa W.H. Chen & Y.M. Shui and O. wenshanensis W.H. Chen & Y.M. Shui and another pair grows in Yongde county, Southwest Yunnan, viz. O. fulva W.H. Chen & Y.M. Shui and O. lacerata W.H. Chen & Y.M. Shui. Their morphological and geographical relationship with similar species is discussed and the IUCN endangered status is provided, based on the available data.


Introduction
In China, Southeast Yunnan and Southwest Yunnan are rich in species diversity of the genus Oreocharis s.l. (Gesneriaceae) (Fig. 1, Wang 2005, Möller et al. 2011).   (Li and Wang 2005, Möller et al. 2011, Tan et al. 2013, Rossini and Freitas 2014, Tan et al. 2015. Amongst them, O. concava var. angustifolia, O. flabellata, O. begoniifolia, O. rhytidophylla, O. tsaii and O. yunnanensis are endemic to SW Yunnan. Amongst the two species without morphology of flowers in the protologue (Li 1983), O. rhytidophylla has been supplemented  and O. flabellata has still not been confirmed up to now.  (Li and Wang 2005, Möller et al. 2011, Chen et al. 2012, 2017, Cai et al. 2015. Nevertheless, the recent exploration reveals that there are an additional four new species needing to be described in the genus from Yongde county of Lincang District in SW Yunnan and Wenshan county of Wenshan Zhuang and Miao Autonomous Prefecture in SE Yunnan (Figs 2, 3). The new findings complement the species richness of the genus in the above regions in China ( Fig. 1; Wang et al. 1990, Wang et al. 1998onwards, Li and Wang 2005, Liu and Peng 2010, Shui and Chen 2010. The four new species have been recently confirmed, based on the morphological evidence instead of molecular data in the expanded genus. Firstly, the recent combined analysis of ITS and trnL-F revealed the possible rapid radiation and low resolution of the phylogenetic trees (Möller et al. 2011, Chen et al. 2014, implying that the molecular data from few molecular makers just provide affinity between similar endemic species rather than whether or not they are conspecific. Therefore, more molecular makers, transcriptome or genome data will need to be adopted to resolve the above question. Secondly, based on the recent phylogenetic study, the genus seems to be divided into two groups, which are dominated respectively by diandrous or tetrandrous flowers with purple flowers, south-eastern China distribution and usually less than 1600 m elevation and by tetrandrous flowers with yellow flowers, south-western China and usually more than 2000 m elevation (Möller et al. 2011, Chen et al. 2014, Zhang et al. 2018. Thus, the four new species which we proposed should be a member of the second group because of the tetrandrous, yellow-flowered and more than 2000 m elevation. Thirdly, amongst the second group, we consulted the actual specimens and on-line images in the important herbaria in China (KUN, PE) and worldwide (BM, E, K, P) and confirmed the potential similarity of the new species we proposed. Furthermore, due to the high endemism in the genus, we paid more attention to the species growing in the same regions and designed an identification key to differentiate the new species and the other species of the two species groups, respectively from SW Yunnan and SE Yunnan, China. Finally, we provided both the tables showing the differences between the new species and the most similar species, as well as colour figures showing their detailed and actual morphology besides their illustration. The above new discovery depended on the long-term field exploration from the local forestry staff. In general, most of the species in Oreocharis are prone to grow on the north-facing shady slope nearby the summit, especially in SW China (Li and Wang 2005) and so it is difficult to find them in the field except in inaccessible localities. For example, as for Orocharis wenshanensis W.H.Chen & Y.M.Shui in the core region of Wenshan Laojunshan National Nature Reserve, the staff (DMH in authorship) of the Natural Reserve had searched for it for several years since 2008 and found it in 2013 even if the preliminary record was from the previous intergraded surveys (Shui et al. 2008). Another example is from the staff member (YLL) of the forestry department of Yongde county. He also went to the core regions of Yongde Daxueshan National Nature Reserve to search for it in 2013 even if the information on record was from the previous intergraded surveys in 2003 (Liu and Peng 2010). Therefore, during the exploration of the genus, the local staff provided considerable contributions to the new discovery for science and to the conservation of the regional biodiversity. Description. Herb perennial and stemless, rhizomatous. Leaves basal; petiole 4-8 cm, densely brown villous; leaf blade ovate, thickly chartaceous, 4.0-5.2 × 3.0-3.5 cm, adaxially setulose and rugose, abaxially glabrous amongst veins, sparsely brown villous along veins, base cordate, apex acute, margin biserrate, lateral veins 5-6 on each side of midrib, indistinct adaxially and distinct abaxially. Inflorescences axillary; peduncle 9-13 cm, densely brown villous; bracts 2, leaf-like, broadly ovate, 7-10 × ca. 5 mm, adaxially glabrous and abaxially villous, margin serrate. Pedicel 1-2.5 cm, villous. Calyx ca. 6 mm, 5-sect from 1/3; segments equal, triangular, ca. 4 × 1.5-2 mm, margin entire below top, top crenate, adaxially glabrous, abaxially pubescent. Corolla yellow, 1.6-2.9 cm, outside strigose and inside glabrous; tube campanulate-cylindric, gradually slightly widening from middle of tube, 1.3-2 cm, 0.3-0.4 cm in diam., throat not constricted; limb 2-lipped; adaxial lip smaller, 3-5 mm, emarginate; abaxial lip larger, 3-lobed, lobes oblong, apex rounded, central lobe ovate, ca. 7 × 5 mm, lateral lobes rotund, ca. 5 × 5 mm. Stamens 4, coherent in 2 pairs, included, adaxial stamens 3-6 mm, adnate to corolla tube 7-13 mm from base, abaxial stamens 3-4 mm, adnate to corolla tube 13-16 mm from base; filaments tender, glabrous; anthers basifixed, oblong, 2-loculed, dehiscing longitudinally; staminode ca. 0.5 mm, adnate to corolla tube ca. 8 mm. Disc ring-like, 1-2 mm, 5-lobed shallowly. Pistil 0.9-1.8 cm, pubescent; ovary oblong, pubescent, 0.5-1.2 cm, 1-loculed; style glabrous, 0.4-0.6 cm; stigma 1, 2-lobed. Capsule straight, narrowly oblong, 3.4-4 cm × 0.8-0.9 cm, existing style ca. 0.7 cm. Seeds not seen. Etymology. The species is named after the pubescent fruits (Fig. 2F).
Distribution, habitat and phenology. This species is only distributed in Yongde, Yunnan Province and grows on the rocks in montane forests. Flowering is September-October and fruiting is September-November.
Etymology. The epithet "fulva" is named after the golden-brown villi on the plants.
Etymology. The species is named after the lacerate leaves. Conservation status. The new species has been observed only from the type locality. The preliminary observation revealed that there are 300 mature individuals and ca. 600 m 2 (20 m × 30 m) area nearby the summit in the core area of the nature reserve, almost never to be affected by the activity of the local people. According to the IUCN Red List Categories and Criteria, the new species is hereby assessed as "Vulnerable (VU)"(D). (IUCN 2012) Additional specimens examined (paratypes). CHINA. Yunnan province: Lincang district, Yongde county, Wumulong community, Ganhe village, Daliang Mt., 99°38'58"E, 24°08'56"N, on rocks in shrubs, elev. 2,902 m, flowers yellow, common, 11 August 2003, in flower, Zi S.S. 261 (KUN, PE); the same locality, elev. 2, 900 m, rare,16 September 2013, Li Yong-Liang YDDXS 1137.
Distribution, habitat and phenology. The new species only grows in the montane forest in Wenshan county, Yunnan Province of China. Flowering is July-September; and fruiting is October-January the following year.
Etymology. The species is named after the type locality of the new species. Conservation status. Currently, the new species has been observed only from the type locality. The more than two years observation revealed that there are ca. 50 mature individuals and ca. 300 m 2 (10 m × 30 m) area nearby the summit in the core area of the nature reserve, similarly to the above species (O. lacerata). According to the IUCN Red List Categories and Criteria, the new species is hereby assessed as "Critically Endangered (CR)" (D1+D2). (IUCN 2012)  Li and Wang (2005) possibly because of their similar locality in SE Yunnan. However, the latter species endemically grows in the limestone forests in Xichou county, the neighbouring county of Wenshan county, a very different habitat from Oreocharis wenshanensis. Furthermore, the new species we proposed can be easily distinguished from Oreocharis aurea Dunn var. cordato-ovata by its broadly ovate blade, smaller corolla without contracted throat and bilobed adaxial corolla lips (Li and Wang 2005). In fact, due to its 2700 m elevation, it is morphologically more similar to O. concava from NW Yunnan with 3100-3400 m elevation (Fig. 7, Table 4). After more than 20 years of observation, with the support of local staff of the Nature Reserve, we made a long-term observation from 1993 to 2018 and confirmed its taxonomic novelty.