Oxytropis jamsranii (Fabaceae, Papilionoideae, Astragaleae), a new species of section Xerobia from Mongolia

The genus <i>Oxytropis</i> L. (Fabaceae) comprises over 600 accepted species, ranking amongst the largest in the family. Nearly 100 <i>Oxytropis</i> taxa have been reported from Mongolia, spanning five subgenera and 20 sections in Mongolia. In this study, a new species, <i>Oxytropis jamsranii</i> Munkht. & Baasanm., from the Ikh Bogd Mountains in Mongolia, is described and illustrated. Based on morphological characteristics, it belongs to the section Xerobia. Although similar to <i>O. leptophylla</i> and <i>O. sobolevskajae</i> within the section, <i>O. jamsranii</i> is clearly distinguished by its indumentum, raceme structure, leaflet number and shape and corolla colour. The first occurrence of <i>O. sobolevskajae</i> - previously known only from the Republic of Tuva of Russia - in the flora of Mongolia is also reported here. Taxonomic nomenclature, morphological descriptions, distribution maps and field photographs for the new species and its two close relatives are provided.