SALVIA SUBVIOLACEA, A NEW SPECIES FROM THE HIMALAYAS–HENGDUAN MOUNTAINS, CHINA

Salvia subviolacea Y.K.Wei & Pendry, a new species from China, is described. Salvia subviolacea belongs to Salvia subg. Glutinaria (Raf.) G.X.Hu, C.L.Xiang & B.T.Drew, sect. Eurysphace E.Peter, and is distinguished from morphologically similar species by differences in its habit, leaves, inflorescences and flowers. It has a disjunct distribution in Sichuan and Xizang, and its IUCN Red List conservation assessment is Endangered. The Xizang population is under extreme threat and rapid conservation measures need to be taken.


Introduction
The Hengduan Mountains are the easternmost extension of the Himalayas and are located in the Sichuan, Xizang and Yunnan Provinces of China. More than half of China's 83 species of Salvia L. are found in these provinces, and 23 species are endemic to the Hengduan Mountains (Wei et al., 2015). The diversity of this region has still not been fully explored, and further investigations are much needed (Li & Hedge, 1994;Wei et al., 2015), because new species of Salvia are still likely to be found there (Wang et al., 2016). In this paper, we describe a new species of Salvia from Sichuan and Xizang and present a key to related species. Future papers will describe and document the ongoing research programme.
In 2011 and 2014, we collected a Salvia in Sichuan and Xizang that showed similarities to Salvia dolichantha E.Peter, S. hians Royle ex Benth., S. przewalskii Maxim. and S. wardii E.Peter but proved to be different from all these species. Further investigations in the field and comparison with herbarium specimens and living plants of these species have confirmed that our collections represent a new species, which is described and illustrated below.
Two subsequent surveys of the Xizang population in 2019 and 2020 found evidence of serious disturbance at the collecting locality, and no living plants could be located. It is evident that immediate measures need to be taken to protect this species.
Ecology. Forest margins and understorey, roadsides. It is apparently well adapted to various habitats. Flower colour is apparently influenced by environment, with a deeper colour in drier, sunnier locations.
Phenology. Flowering June to July, fruiting July to August.
Distribution. Salvia subviolacea is endemic to China and is currently known only from the type locality at Yanyuan, Sichuan Province, and Linzhi, Xizang Province.
Conservation status. Salvia subviolacea has been observed at only two sites, which are  about 360 km apart, among 403 localities surveyed for Salvia across Sichuan (83), Xizang (49) and Yunnan (271). Whereas the Sichuan population appears for now to be relatively steady, with between 250 and 2500 mature individuals, the Xizang population is under extreme threat. In 2019 this location was revisited but no living plants were found. The conservation assessment is therefore EN B2ac(iii) or C2b (IUCN Standards and Petitions Subcommittee, 2017).
Etymology. The epithet refers to the pale violet colour of the corolla. Similarities and differences between these species are summarised in the Table, and their comparative morphology is shown in Figure 2.
Living material was collected but the plants have not survived at Shanghai Chenshan Botanical Garden. We will attempt to set up ex situ collections at the Kunming Institute of Botany, Yunnan. Wu & Li (1977) placed the Chinese species of Salvia in three subgenera (i.e. subg. Allagospadonopsis, subg. Salvia and subg. Sclarea) based on stamen structure and whether their lower arms are fertile and united. However, this classification has some obvious discrepancies, such as Salvia nipponica Miq. being placed in subg. Salvia despite its sterile lower arms, which place it in subg. Sclarea. Similarly, Salvia substolonifera E.Peter was incorrectly placed in subg. Allagospadonopisis when it actually belongs to subg. Salvia because of its fertile lower arms. A comprehensive re-examination of the Chinese Salvia was clearly much needed, with a particular emphasis on flowers from living plants. Hu et al. (2018) established a new subgenus, Glutinaria (Raf.) G.X.Hu, C.L.Xiang & B.T.Drew, based on molecular evidence, and treated eight major subclades within it as sections. Section Eurysphace, with 45 species, is the largest of these sections and the vast majority of its species have a Sino-Himalayan distribution and are found at high elevations. These species were divided into two subsections: subsect. Annuae and subsect. Perennes. Subsection Annuae comprises three annual or biennial species (Salvia roborowskii Maxim., S. tricuspis Franch. and S. umbratica Hance), and subsect. Perennes includes 42 species (Hu et al., 2018).

Discussion
The species of subsect. Perennes can be divided into two groups -short connective and long connective -based on the relative ratio of connective to filament. In the shortconnective group, the connective is obviously shorter than the filament, whereas in the long-connective group the connective equals or is longer than the filament. Within the shortconnective group, there is a clear distinction between the species with smaller corollas (never exceeding 3 cm; mean, 2.5 cm) and of small stature (height less than 30 cm) and larger plants with corollas that exceed 3 cm (mean, almost 4 cm).