Nicolai M. Nürk

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The páramos, high-elevation Andean grasslands ranging from ca. 2800 m to the snow line, harbor one of the fastest evolving biomes worldwide since their appearance in the northern Andes 3-5 million years (Ma) ago. Hypericum (St. John's wort), with over 65% of its Neotropical species, has a center of diversity in these high Mountain ecosystems. Using nuclear(More)
Phylogenetic hypotheses for the large cosmopolitan genus Hypericum (St. John's wort) have previously been based on morphology, and molecular studies have thus far included only a few species. In this study, we used 360 sequences of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (nrDNA) for 206 species representing Hypericum (incl.(More)
The genus Hypericum L. (St. John's wort, Hypericaceae) includes more than 450 species that occur in temperature or tropical mountain regions of the world. Monographic work on the genus has resulted in the recognition and description of 36 taxonomic sections, delineated by specific combinations of morphological characteristics and biogeographic distribution.(More)
Our aim is to understand the evolution of species-rich plant groups that shifted from tropical into cold/temperate biomes. It is well known that climate affects evolutionary processes, such as how fast species diversify, species range shifts, and species distributions. Many plant lineages may have gone extinct in the Northern Hemisphere due to Late Eocene(More)
The genus Urtica L. is subcosmopolitan, found on all continents (except Antarctica) and most extratropical islands and ranges from Alaska to Patagonia, Spitzbergen to the Cape and Camtschatka to the subantarctic islands. However, throughout its geographical range morphologically nearly indistinguishable species are found alongside morphologically quite(More)
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