Two new species of Potentilla (Rosaceae) from the Intermountain Region of western U.S.A.

Two new species ofPotentilla from the Intermountain West (U.S.A.) are described and illustrated here for the first time.Potentilla cottamii is known only from the higher quartzite slopes of the Pilot Range and the Raft River Mountains of western Box Elder Co., Utah and adjacent Elko Co., Nevada in the Great Basin. It most closely resemblesP. hyparctica, P. robbinsiana, andP. frigida, which may be its closest living relatives.Potentilla angelliae is known only from one collection from a subalpine meadow on Boulder Mountain of the Aquarius Plateau in southern Utah. It most closely resemblesP. crinita, P. subjuga, andP. bicrenata, the first of which is considered to be its closest relative.