###### Abstract
However, the species diversification and their biogeographical patterns in this region need to be further understood by explicitly analyzing the effects of those complicated events, including tectonic movements induced by the Indo-Eurasian collision [36], the emergence of Asian monsoons [37; 38], and climatic oscillation induced by glacial cycles [39]. _Clematis_ sect. _Tubulose_ presents an opportunity to study species diversification and formation of distribution in response to geology and climate change in the SJFR. The genus _Clematis_ L is one of the few cosmopolitan genera in the family Ranunculaceae, with about 300 wild species, most of which are diploid vine species [40; 41]. The genus has undergone rapid species radiations over the last five million years during the Plio-Pleistocene epoch, according to previous molecular studies [42; 43]. Sect. _Tubulose_ is a distinct group in _Clematis_ endemic to East Asia. It is characterized by its erect herbaceous or sub-shrub habit, termate leaves, and bell-shaped (sepals erect) flowers (often blue) with hairy anthers. Morphologically, this _Clematis_ group was traditionally considered to be closely related to other groups with bell-shaped flowers and hairy anthers in the genus, such as sect. _Campanella_[40]. The latest _Clematis_ classification [41] argued that sect. _Tubulose_ may be more closely related to sect. _Clematis_ (sepals spreading with glabrous anthers) rather than to sect. _Campanella_. According to the new taxonomic revision [44], sect. _Tubulose_ was divided into two subsections, subsect. _Pinnata_ ([PERSON]) [PERSON] and subsect. _Tubulose_ (Decne.) [PERSON]. Subsect. _Pinnata_ includes two controversial taxa, _C. takedana_ and _C. pinnata_, which were known or had been tested to be the hybrids between sect. _Clematis_ and sect. _Tubulose_[45; 46]. For this reason, this study discusses the evolutionary issue of sect. _Tubulose_ by excluding those two hybrid taxa. Species of sect. _Tubulose_ occur solely in East Asia [40; 44]. With the exclusion of _C. takedana_ and _C. pinnata_ (_C. tartarinovii_ as its synonymy) [47], seven species and two varieties were included in the sect. _Tubulose_[44], which were widely distributed in mainland China (mainly in northern and eastern provinces), Taiwan island, the Korean Peninsula, and the Japan archipelago (Figure 1). Three taxa, _C. heracleifolia_, _C. tubulosa_, and _C. tubulosa_ var. _ichangensis_, occur in mainland China. The former two taxa are distributed in northern China and often occur together, whereas _C. tubulosa_ var. _ichangensis_ is distributed relatively in the south range of the sect. _Tubulosa_ in Hubei, Henan, Hunan, Shaanxi, Shanxi, and Anhui Provinces, with some rare populations occurring in Guizhou and Zhejiang Provinces (Figure 1). The other six taxa are distributed in the Korean Peninsula and the insular system of East Asia, all of which are narrow endemics. Among them, one (_C. urticifolia_) is in the Korean Peninsula, three (_C. stans_, _C. stans_ var. _austrojaponensis_, and _C. speciosa_) are in the Japanese archipelago, and two (_C. psilandra_ and _C. tsugetorum_) are in Taiwan island. The historical origin of this East Asian section and the formation of its distribution patterns are interesting issues worthy of further investigation. In this study, we hypothesize that the species diversification and the range formation of sect. _Tubulosae_ were triggered by topographical events and climate changes during the Plio-Pleistocene epoch, as suggested by previously published molecular dating analysis of the genus [43], and the island species of this section evolved allopatrically due to the intermittent land bridges in the East China Sea during the Quaternary ice ages. A robust phylogeny is a prerequisite for understanding the origin and evolution of a certain plant taxon.