Evolutionary assembly of flowering plants into sky islands

Alpine floras (plants in the vegetation belts above climatic treelines) experience cold climates, particularly temperate mountains during winter, but they are generally species-rich. Yet, biogeographers have not determined whether these represent evolutionarily independent convergent assemblages drawn from their regional floras, or originated particular clades pre-adapted to harsh conditions. Here, we analyse evolutionary relationships of angiosperm (flowering plant) species 63 alpine worldwide (~7,000 species) comparison with (~94,000 and entire global flora. We find that each represents an assemblage more closely related than respective floras. The degree phylogenetic clustering tropical exceeds mountains. However, relation flora, phylogenetically subsets colonized areas interglacial periods. conclude include a few dominant families evolved tolerance low temperature, niche conservatism explains clustering, compared pools. By analysing worldwide, authors