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The ecotone of ecological communities is usually rich in species and complex in floristic components, which is regarded as a key zone. Budanla Mountain is located in the transition zone of semi-humid to semi-arid ecological environment in Tibet. Because of its special natural geographical environment, it has rich mountain plant diversity. However, the composition and floristic characteristics of seed plants in this important ecological transition area are still not well understood. In order to clarify the floristic composition and vertical distribution pattern of seed plants on the south slope of Budanla Mountain, the floristic characteristics of seed plants on the south slope of this mountain were systematically studied through field plant community quadrat investigation, laboratory specimen identification and related literature review in this paper, the richness pattern of advantage genera and geographical composition along the altitude gradient was also explored. The results were as follows:(1)There were approximately 316 species of seed plants belonging to 45 families and 156 genera in the south slope of Budanla Mountain, in which there were the most abundant single species and small genera of seed plants, the temperate distribution type was dominant at the genus and species level.(2)In the vertical distribution gradient of geographical elements, the temperate distribution type had a peak value at 4 000 m, including 53 genera, and showed a downward trend with the increase of altitude.(3)The nature of floristic geographical elements and the vertical distribution of species richness in this area might be mainly affected by the local semi-humid climate, local environmental factors and topography. The results of this study can provide important basic data for the study of plant diversity protection and resource utilization in this region. [ABSTRACT FROM AUTHOR]

Large‐scale patterns of biodiversity and formation have garnered increasing attention in biogeography and macroecology. The Qinghai‐Tibet Plateau (QTP) is an ideal area for exploring these issues. However, the QTP consists of multiple geographic subunits, which are understudied. The Kunlun Mountains is a geographical subunit situated in the northern edge of the QTP, in northwest China. The diversity pattern, community phylogenetic structures, and biogeographical roles of the current flora of the Kunlun Mountains were analyzed by collecting and integrating plant distribution, regional geological evolution, and phylogeography. A total of 1911 species, 397 genera, and 75 families present on the Kunlun Mountains, of which 29.8% of the seed plants were endemic to China. The mean divergence time (MDT) of the Kunlun Mountains flora was in the early Miocene (19.40 Ma). Analysis of plant diversity and MDT indicated that the eastern regions of the Kunlun Mountains were the center of species richness, endemic taxa, and ancient taxa. Geographical origins analysis showed that the Kunlun Mountains flora was diverse and that numerous clades were from East Asia and Tethyan. Analysis of geographical origins and geological history together highlighted that the extant biodiversity on the Kunlun Mountains appeared through species recolonization after climatic fluctuations and glaciations during the Quaternary. The nearest taxon index speculated that habitat filtering was the most important driving force for biodiversity patterns. These results suggest that the biogeographical roles of the Kunlun Mountains are corridor and sink, and the corresponding key processes are species extinction and immigration. The Kunlun Mountains also form a barrier, representing a boundary among multiple floras, and convert the Qinghai‐Tibet Plateau into a relatively closed geographical unit. [ABSTRACT FROM AUTHOR]