Allium species of section Rhizomatosa, early members of the Central Asian steppe vegetation. Allium species of section Rhizomatosa

The genus Allium is one of the largest genera in the family of Amaryllidaceae. It comprises over 1000 species and the number is still increasing. The new intergeneric classification system, based on molecular sequence data, subdivided the genus into 15 subgenera and more than seventy sections. For some sections, phylogenetic position of species within the sections remained unresolved. This is also the case of sections Caespitosoprason N.Friesen and Rhizomatosa Egorova. These two sections are confined to central Asia, where they inhabit steppe habitats. This study conducted phylogenetic analysis of most of the taxa of the sections Caespitosoprason and Rhizomatosa with the nuclear marker ITS and three different chloroplast markers (trnQ-rps16, trnL-trnF and rpl32-trnL spacers). Taxonomical remarks, identification key and distribution maps for all species of the section Rhizomatosa Egorova (including all species of section Caespitosoprason) are presented. A new discovered Allium bellulum in the Katun Valley (Altai, Russia) is compared cytological (flowcytometri and karyology) with the other two known localities from Tuva, Russia, and the Buchtarma Valley, Kazakhstan, and the disjunctive distribution is discussed. Divergence time estimates of the species of the section Rhizomatosa and his distribution are in good agreement with the origin and climate/landscape history of the central Asian steppe in Lower Miocene.