New insights into the phylogeny and taxonomy of Chinese species of Gagea (Liliaceae)-speciation through hybridization

A new region of speciation for the genus Gagea (Liliaceae) was investigated (Bogda-Shan and Urumqi; northwestern Xinjiang, China). Two species were recorded as new for the region (G. rufidula, G. davlianidzeae); three species are described as new to science (G. angelae, G. jensii and G. huochengensis). The description of G. nigra is emendated. Sequence data (cpDNA: trnL-trnF IGS+psbA-trnH IGS, nrDNA: ITS), including representatives of all Gagea sections, were used to compare the new species with closely related taxa. A nuclear single copy gene region (pCOS At103) was analysed for representatives of the Sects. Minimae and Gagea. Network analysis of cpDNA and nDNA indicates hybridization and recent speciation in Xinjiang. ITS and pCOS At103 sequences reveal gene flow between G. davlianidzeae and G. nigra. A cpDNA haplotype network constructed from representatives of Sect. Gagea was highly informative phylogenetically. Gagea angelae and G. huochengensis, sharing gene flow, are related closely to a basal clade represented by G. ancestralis, G. xiphoidea and G. capusii, which may include the putative progenitor of all other taxa of the large Eurasian Sect. Gagea. Whereas speciation in Sect. Minimae seems to be driven mainly by hybridization, speciation in the Sect. Gagea may be influenced by both hybridization and geographical separation. We confirm the monophyly of Sects. Bulbiferae and Minimae.