Fig. 1

Cushion willow distribution pattern and locations of population samples. a Female individual with flowers. b Male individual with flowers. c Low elevation Cushion willow population located on open river bank at an elevation of 2950 m above sea level. d High elevation Cushion willow population on a scree slope at an elevation of 4000 m. e Sample locations of the 14 Cushion willow populations in HDM and nearby area of the eastern Himalaya. Pie charts at sampling locations indicate the distribution of genetic groups identified by a Structure analysis of the population. f Scheme of sky island distribution pattern