Lysimachia tianmaensis (Primulaceae), a new species from Anhui, China

Abstract A new species of Lysimachia (Primulaceae), Lysimachia tianmaensis K. Liu, S.B. Zhou & Ying Wang sp. nov., is described and illustrated from Jinzhai County, Anhui, China. It is endemic to Dabieshan Mountain, China. The new species has yellow flowers and belongs to the subgenus Lysimachia section Nummularia series Grammicae. It is very easily distinguishable from other related species by having alternate leaves with brown patches beneath and an auriculated leaf base.


Introduction
Lysimachia Linnaeus is one of the largest genera of Primulaceae s. l. and it comprises about 200 species, mainly distributed in the temperate and subtropical parts of the northern hemisphere, as well as in some tropical mountain regions (Chen and Hu 1979, Hu and Kelso 1996, Marr and Bohm 1997, Hao et al. 2004, Julius et al. 2016). On the whole, it is almost cosmopolitan, but the greatest concentration of the species occurs in China (with ca. 140 species; Chen et al. 1989, Hu andKelso 1996). Some new species in Lysimachia are still being found (Peng and Hu 1999, Shao et al. 2004, Shao et al. 2006, Yan and Hao 2012, Liu et al. 2014a, 2014b, Estes et al. 2015, Zhou et al. 2015, Baskose et al. 2016, Julius et al. 2016.
In 2007, during the course of checking specimens in the herbaria of Anhui Normal University, a specimen of Lysimachia caught the authors' attention. This plant was collected by Shen in 1983 from Jinzhai County, Anhui Province and was not identified. This plant has alternate leaves and an obvious broadly-winged petiole with an auriculate base. It should thus represent an undescribed species, as this character combination is not known from any other species. In 2008-2009, the authors made several botanical expeditions to Tianma Nature Reserve, in Jinzhai County, Anhui Province. Many populations of this plant were found bearing flowers or fruits there. In this paper, this plant and related species were comparatively studied.

Materials and methods
Vouchers of Lysimachia tianmaensis were collected from Tianma National Nature Reserve of Anhui. Gross morphology and phenology data were obtained during the field expedition. Descriptions were collected from living plants. Diagnosis. Lysimachia tianmaensis is similar to Lysimachia grammica Hance in the alternate leaves, but differs by having a larger blade with brown patches beneath, an auriculate leaf base and subcapitate inflorescences.

Distribution and habitat.
Lysimachia tianmaensis is endemic to Dabieshan Mt., China (including Jinzhai County, Yingshan County etc.), growing at margins of mountain woodlands, roadsides or under broad-leaved forests at altitudes of 600-1200 m.
Etymology. The epithet "tianmaensis" is derived from the type locality, Tianma National Nature Reserve, Jinzhai Xian, Anhui Province, China. Vernacular name. China: tian ma guo lu huang. Phenology. Flowering April-June, fruiting June-August. Conservation status. A large number of populations of Lysimachia tianmaensis were found during the extensive investigation in Tianma National Nature Reserve. This species is also distributed in other areas in Dabieshan Mt. as well as Tianma National Nature Reserve. This species often grows under broad-leaved forests above 600 m. This species is fairly common there and therefore proposed as Least Concern following the IUCN Red List Criteria (IUCN 2016).

Discussion
Lysimachia tianmaensis is quite distinct from all other species in subgenus Lysimachia. Its morphological affinity is with L. grammica, L. remota Petitmengin and L. pseudohenryi Pampanini, but it can be easily distinguished by some characters (Table 1). L. remota, a member of subgenus Lysimachia, section Nummularia, series Deltoideae, is characterised by opposite leaves with sparsely transparent glandular punctate. L. pseudohenryi has opposite leaves and terminal racemes, often nearly capitate, belonging to  Chen and Hu (1979). Series Grammicae is a well-defined group, so far consisting of only one species. L. grammica is a widely distributed species with its distribution centre in Anhui, Henan, Hubei, Jiangsu, Jiangxi, S Shaanxi and Zhengjiang and the new species is endemic to Dabieshan Mt. However, the new endemic species rarely, if ever, co-occurs with the widespread L. grammica in intermixed populations because of the distinct altitudes for each natural habitat (L. tianmaensis: 600-1200 m; L. grammica 0-600 m, rarely to 800 m). The new species has a larger lamina with brown patches beneath than that of L. grammica with blank glandular striates. Moreover, the leaves of the new species are characterised with an obvious auriculate base. Based on these characters, L. tianmaensis can be very readily distinguished from L. grammica.