Floristic Diversity along an Altitudinal Gradient in Namgia Valley of Cold Desert in District Kinnaur, Himachal Pradesh

A study was carried out to know the floristic diversity along an altitudinal gradient with elevations varying from 3000m to 5000m above msl in Namgia valley falling in cold desert area of district Kinnaur, Himachal Pradesh during 2007. Total number of plant species was 142 belonging to 49 families and 105 genera. The dominant families were Asteraceae, Polygonaceae, Ranunculaceae and Rosaceae. The number of tree species at 3000-3500m elevation was 8 with the dominance of Populus nigra. The number of shrub species were 17, 8, 6 and 2 at the elevation of 3000-3500m, 3500-4000m, 4000-4500m and 4500-5000m respectively while number of herb species were 72, 62, 42 and 32 species at the same elevations. Juniperus communis taking shape of dominant shrub at 3500-4000m and 4000-4500m elevations. Ephedra gerardiana was dominant herb at 3000-3500m and 3500-4000m elevations. The distribution pattern of most of the plant species was contiguous in all altitudes. Index of diversity for herb species at different elevations ranges was 3.56, 3.25, 3.14 and 3.04. Out of 64 medicinal plant species recorded from the area, 13 species fall in the threatened category.