Onosma nuristanica (Boraginaceae), a new species from Afghanistan

The new species Onosma nuristanica is described and illustrated here on the basis of specimens collected from Parun in Nuristan and Chapa Dareh in Kunar, one of the eastern provinces of Afghanistan. An extensive review of the literature and a comparative study with specimens from several herbaria led to the determine of this new species. Our results represent significant divergence between studied specimens in terms of the most important morphological features, i.e., flower color, pedicel length, bract length filaments length, cauline shape and form.  In this article, a detailed description of the new species and a diagnostic key for Onosma species thriving in Afghanistan are provided and the new species is compared morphologically with its closely related species. In addition, a distribution map is provided for the new species and its close relatives in the area.