Maximum Likelihood tree based on 12,502 SNP markers derived from DArT sequencing of 16 taxa, including 15 taxa of Ptilagrostis and an outgroup (Ptilagrostiella kingii). Numbers on branches are bootstrap values. Abbreviations: Ptilagrostis alpina – P. alp, P. arcuata – P. arc, P. bhutanica – P. bhut, P. chingii – P. chin, P. concinna – P. conc, P. contracta – P. cont, P. dichotoma var. dichotoma – P. dich, P. dichotoma var. roshevitsiana – P. ros, P. duthiei – P. dut, P. glabrifolia – P. gla, P. junatovii – P. jun, Ptilagrostiella kingii – Pt. kin, P. luquensis – P. luq, P. malyschevii – P. mal, P. mongholica – P. mon, P. yadongensis – P. yad. List of samples is given in Suppl. material 1.