Trolliusaustrosibiricus (Ranunculaceae), a new species from South Siberia

Abstract Trolliusaustrosibiricus Erst & Luferov, sp. nov., a new species from Russian South Siberia is described and illustrated. This new species is endemic to Western and Central Siberia. Morphologically, it is close to the East Asian species T.chinensis and T.macropetalus. However, it differs from the aforementioned species due to the morphology of the rhizomes, aerial shoots, sepals and petals. This species is also distinguished from T.asiaticus, which is widespread in Russia (Western and Eastern Siberia), Mongolia, China, north-eastern Kazakhstan and in the northeast of the European part of Russia, in having a smaller number of sepals, longer persistent styles and petals longer than sepals. In addition, an identification key for all Russian species is given and all species have been discussed.


Introduction
Trollius L. (Ranunculaceae) is distributed in temperate to arctic regions of the Northern Hemisphere and has two centres of diversity in SW China and the area ranging from Siberia, the Pamirs and Kashmir (Doroczewska 1974). The genus is characterised by conspicuous orange-or yellow-coloured flowers, similarly coloured petals, subscapose habit and ternate or deeply 3-lobed leaves (Kadota 1987). Trollius is distinguished by an unusual floral structure with petals divided into blade, pit (nectarostigma) and claw (Wang et al. 2010). Length ratio of nectaries to stamens has been considered to be one of the most important morphological characters for species delimitation (Schipczinsky 1937, Siplivinsky 1972, Kadota 1987, Tamura 1995, Luferov et al. 2018. Species belonging to the T. sect. Longipetala Dorosz. are characterised by linear, flat, thin petals, which are longer than the sepals or nearly equal to them. All representatives belonging to this group, except T. asiaticus, are common to the Far East part of Asia. All Siberian species are characterised by petals shorter or equal to sepals. When carrying out a revision of the genus for Russia, we focused on specimens whose petals are much longer than the sepals. Further revision of the herbarium material allowed us to describe a new species of Trollius from South Siberia.

Methods
The revision of herbarium material was undertaken in the herbaria LE, MHA, ALTB, NS and NSK (Thiers 2017). The drawings of Trollius austrosibiricus are based on the images of the type specimens (NS-0013097). The photographs in the field were taken by a Nikon D90 camera. The morphological characters were measured using AxioVision 4.8. The flowering and fruiting periods and habitats are given as cited on the collector's labels. The IUCN Red List Categories and Criteria (IUCN 2016) were applied to assess the conservation status. All revised localities of Trollius austrosibiricus mentioned in the paper are shown on a map ( Fig. 1)   Diagnosis. Trollius austrosibiricus is morphologically close to T. chinensis Bunge and T. macropetalus (Regel) Fr.Schmidt. It differs from these species in simple rhizomes, shorter aerial shoots, smaller flowers and shorter persistent styles. The new species is distinguished from T. asiaticus L. by a smaller number of sepals, longer persistent styles and petals longer than sepals.
This new species is distinguished from T. asiaticus L. by a smaller number of sepals, longer persistent styles and petals longer than sepals (Table 1). Trollius asiaticus grows mainly in extra-tropical Asia (Western and Eastern Siberia, Mongolia, northeast Kazakhstan and China), as well as in the northeast of European Russia (Schipczinsky 1937, Siplivinsky 1972, Doroczewska 1974, Borodina-Grabovskaya 2001, Friesen 2003. Phenology. Flowering from April-early May; fruiting in May. Distribution. Trollius austrosibiricus is endemic to mountainous areas of the southern part of Western and Central Siberia. Russia: Tuva Republic, Kemerovo district, Krasnoyarsk territory, Khakassia (Figure 1).
Habitat and ecology. Trollius austrosibiricus grows in subalpine and forest zones, in moist valleys at 350-2400 m elevation. It occurs in forest glades and fringes, in mixed-grass and mixed-grass-cereal dry and swampy meadows, along the banks of rivers, streams and small ponds with fresh water.
Etymology. The specific epithet of the new species is derived from the type locality, South Siberia, Russia.
Preliminary conservation assessment. No appropriate data on abundance and/ or distribution of the taxon are available. It can be included in the Not Evaluated (NE) category of IUCN Red List Categories (IUCN 2016) as it lacks adequate information Style length, mm 1.5-3 3-4 3.5-5 0.5-1(2)

Persistent style shape
Almost erect at the base, above: bent arc-like inwards Bent outwards at the base, above: bent slightly arc-like towards the centre of the flower Bent outwards at the base, above: bent slightly arc-like towards the centre of the flower Bent sharply arc-like towards the centre of the flower to make a direct or indirect assessment of its risk of extinction based on its distribution and/or population status.

Discussion
According to our data, 16 species of Trollius occur in Russia. The "Flora of the USSR" includes 11 species of Trollius, one of which is not found in Russia: T. dschungaricus Regel is confined to the east of Central Asia and China (Schipczinsky 1937 It should be noted that many morphological characters used to distinguish between species and groups of species are not fully developed, do not cover the entire morphological diversity of the genus Trollius and are very variable (many hybridogenic taxa have not yet been described, many species ecomorphs are not yet known). For proper identification, classification and understanding of groups in the genus Trollius, complex studies are needed, including micro-and macro-morphological, molecular phylogenetic, cytogenetic etc. This paper presents the results of taxonomic studies that enabled development of the key to identification of the Trollius species, based on the novel morphological and rhythmological features: for example, indication of the falling (in T. chartosepalus) and non-falling sepals (in other species), shape, the size of sepals, petals, persistent styles, their size ratio, the colour of the flower elements, leaflets and stigmas. According the most recent data, the key for Trollius identification (from Russia) is provided by us.