Botanist John Thomas Howell transferred Tweedy's mousetail to Potentilla tweedyi in 1945,[4] however this change was not widely accepted for many years.

It has finely-dissected, pinnate basal leaves which often lie somewhat flat, appearing to radiate from the central root crown.

The reddish or purplish stems are glandular and usually finely hairy above, each with 1 to 3 small leaves and topped with a cluster of several flowers.

[8] Potentilla tweedyi is endemic to the Pacific Northwest in the United States, growing in central and northeastern Washington, northern Idaho, and northwestern-most Montana (Mineral County).

[11] Per Axel Rydberg gave the species epithet tweedyi in honor of Frank Tweedy, who made the first collection, in the Yakima area of Washington Territory in 1883.