Woolly Cinquefoil

Potentilla argyrea Rydberg, sp. nov
Perennial, with a tap-root and short caudex ; stems erect or nearly so, white-tomentose and silky; basal leaves pinnate, with 7-9 leaflets, 6-12 cm. long; petioles 3-6 cm. long, white-tomentose ; leaflets oblanceolate or oblong-obovate, 1-3 cm. long, white-tomentose on both sides, coarsely crenate with ovate teeth ; stem-leaves similar but smaller and the leaflets more crowded ; inflorescence dense and contracted ; stipules ovate, acuminate, entire, about 1 cm. long ; hypanthium white silky-villous, in fruit 6 mm. broad ; bractlets lanceolate, almost equaling the sepals in length ; sepals ovate, acute, 4-5 mm. long ; petals obcordate, 5 mm. long; stamens about 20; pistils many; styles filiform.
Type collected at Moose Jaw, Assiniboia [Saskatchewan], in 1896, John Macoun 14441 (herb. N. Y. Bot. Gard.).
Distribution : Plains of Saskatchewan and North Dakota.