A new species of the genus Potentilla L. (Rosaceae) from the Tehran province (Iran)

Potentilla alborzensis Faghir & Attar, sp. nov. (Rosaceae) is collected from steppe Mountains of Tang-e Washi, in the middle of Alborz Mountains for the first time. The new species is related to section Aureae (Rydb.) Juz. for its palmate radical leaves, having straight hairs and glandular trichomes; corymbiform inflorescence; hairy and glandular sepals; clavate and papillose style, shorter than or as long as matured ovary. Detailed micro- and macromorphological descriptions of the newly collected species, as well as photographs and distribution map are provided. In addition, comparison of diagnostic traits with allied species especially P. crantzii (Crantz) Beck ex Fritsch, P. adenophylla Boiss. & Hohenack., P. gelida C. A. Mey., P. geranioides Willd. and identification key are presented.