Northern Prairie Wildlife Research Center
Every county in North Dakota probably has a population of tall cinquefoil. The plant ranges across southern Canada, the northeastern states, and southwest to Colorado and Oklahoma.
Tall cinquefoil is a densely hairy perennial from thick roots. Plants stand up to 4 feet tall, but average specimens are less than half that height. The highly-toothed leaves are cleft into 7 to 11 leaflets. Most of the leaves are basal, but one or two form on the stem. Several clusters of 2 to 6, white-petalled flowers about 1/2 inch wide form at the tip of the stem and just below it. Fruits are tiny brown achenes.
Look for tall cinquefoil on lightly or moderately grazed native prairie. The leaves and roots of many Potentillas are used in teas and medicines, but none of the references available to me mention the species discussed here. This is true for many of our prairie plants whose ethnobotanical history was lost or never recorded.
The cinquefoils (meaning "five-leaved") are members of the rose family (Rosaceae). Rose is an ancient Latin name. The family contains about 3000 species, and includes dozens of horticulturally and agriculturally important plants such as mountain-ash, spiraea, pear, apple, cherry, and strawberry. The generic name Potentilla is a diminutive of potens, "powerful," originally applied to silverweed (P. anserina), from its once reputed medicinal powers. The specific epithet arguta means "acute" in botanical Latin, concerning the teeth of the leaflets. Tall cinquefoil was described for science by the German botanist Frederick Pursh in his classic Flora Americae Septentrionale of 1814. Pursh was first to publish upon the many new plants brought back from the wilderness by Lewis and Clark.