Aim We investigated the historical biogeography and diversification of Gentiana L. (Gentianaceae). Our study depicts the origin and dispersal routes of this alpine genus, and the role of the uplift of the Qinghai–Tibet Plateau (QTP) and past climate changes as triggers for its diversification. Location Tibeto‐Himalayan region and world‐wide mountain habitats. Methods Our sampling represents more than 50% of the extant Gentiana species, including all sections across their entire geographical ranges. We investigated the evolutionary history of Gentiana using phylogenetic reconstructions (maximum likelihood and Bayesian inference) of ITS, atpB–rbcL and trnL–trnF sequences, as well as molecular dating with beast. We tested two approaches of ancestral area reconstructions (DEC, DIVA) in BioGeoBEARS and investigated diversification rates using BAMM. Results The common ancestor of Gentiana and subtribe Gentianinae lived in the QTP region at around 34 (25–45) million years ago (Ma), and 40 (29–52) Ma respectively. From the surroundings of the QTP, Gentiana lineages dispersed to eastern China, Taiwan, Europe, North and South America, Australia and New Guinea, from mid‐Miocene onward (c. 15 Ma–present), with only one older dispersal event to Europe (c. 37–21 Ma). Diversification rates gradually increased over time, and two switches of diversification rates were identified in Gentianinae (c. 7 Ma, simultaneously in the Pneumonanthe/Cruciata lineage and in Tripterospermum). Main conclusions Gentiana existed in the QTP region throughout most of its uplift history following the India‐Asia collision. This region acted as the primary source area for dispersals to many areas of the world. Because steady increase in diversification rates coincides with the extension of the QTP, we argue that the museum theory rather than the explosive radiation theory prevails for gentians in this region, although rare shifts of diversification rates are associated with niche shifts across the alpine/subalpine ecotone.

Gentiana is a sub-cosmopolitan temperate genus among the most species-rich in Gentianaceae. Although molecular data (produced via Sanger sequencing) allowed the resolution of phylogenetic relationships between Gentiana and other genera in subtribe Gentianinae, the validity of sections within the genus remains largely untested. In this study, we evaluated the monophyly of all 14 sections attributed to Gentiana, using 294 unlinked anchored loci, the nuclear ribosomal DNA (rDNA) cistron as well as plastid genomes, all produced by anchored hybrid enrichment. We reconstructed phylogenetic relationships by conducting maximum likelihood and Bayesian analyses. These analyses represent a significant improvement over previous taxonomic studies using molecular tools. Our results partly correspond to traditional taxonomic treatments, with several sections being well supported as monophyletic, including Gentiana sect. Calathianae, sect. Ciminalis, sect. Cruciata, sect. Frigida, sect. Gentiana and sect. Pneumonanthe. In contrast, G. sect. Isomeria, sect. Microsperma and sect. Monopodiae were found to be polyphyletic, whereas sect. Dolichocarpa and sect. Fimbricorona were nested within sect. Chondrophyllae. We here provide new taxonomic treatments for these sections, mostly based upon the traditional delineation of their series, which were recovered as monophyletic. In our new treatment, Gentiana encompasses 13 sections. A new determination key to the sections of Gentiana is provided.

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Summary Marsolais, J. V., Pringle, J. S. & White, B. N.: Assessment of random amplified polymorphic DNA (RAPD) as genetic markers for determining the origin of interspecific lilac hybrids. – Taxon 42: 531–537. 1993. – ISSN 0040‐0262. RAPD markers were used to assess the relationship among species, cultivars and hybrids of lilacs. Thirteen random primers were used to examine 87–130 bands per cultivar or hybrid. The percent band sharing among Syringa xchinensis ‘Alba’, S. xchinensis ‘Saugeana’, S. xchinensis ‘Red Rothomagensis’ and S. xpersica, was surprisingly high (98.3 % to 99.6 %), supporting the theory that S. xpersica has the same species parentage as the three S. xchinensis hybrids, but also indicating that all four are of different clonal origin since they do not share 100 % of their bands. The percent band sharing among the hybrids and their putative parental species, S. vulgaris L. (3 selections) and S. protolaciniata P. S. Green & M. C. Chang (2 selections), were also determined. On average the first shared 48.9 % of their bands with the hybrids, and the second shared 50.7 %, thus strongly supporting the postulated parentage. Most bands found in the hybrids were shared with at least one of the selections, but 11 bands were found exclusively in all four hybrids. They might either represent genetic characteristics specific to these hybrids or might indicate that the exact parental selection combination has not yet been studied. The two studied selections of S. protolaciniata shared only 90,7 % of their bands, thus confirming that they are of different provenances. It is felt that RAPD markers will be very useful for assessing the origin of cultivars and hybrids of many plant species.

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