This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Potentilla Robbinsiana Oakes; T. & G. Fl. N. A. 1: 441. 1840.
Potentilla minima A. Gray, Man. 122. 1848.
P. frigida A. Gray, Man. Ed. 5, 154. 1867. Not Vill. 1789.
Depressed, 1/2'-2' high, tufted from a thick woody base, villous-pubescent. Stipules ovate, obtusish, loosely villous; basal leaves petioled, 3-foliolate, those of the flowering stem sessile, small and 3-lobed; leaflets obovate, villous on both sides, and especially so beneath, 2"-4" long, deeply 3-7-dentate above, cuneate or narrowed at the base, obtuse at the apex; flowers solitary, terminal, slender-petioled, yellow, about 3" broad; sepals and bractlets nearly equal, obtuse, slightly shorter than the obcordate petals; stamens about 20; style filiform; achenes glabrous.
P. effusa Dougl.; Lehm. Nov. Stirp. Pug. 2: 8. 1830.
Plant perennial, 6'-18' high, diffusely branched above. Leaves pinnate, tomentose-canescent, but not silky; leaflets 5-11, or those of the upper leaves only 1-3, oblong, obtuse at the apex, commonly cuneate at the base, incised-dentate, 1/2'-1 1/2' long; flowers yellow, 3"-5" broad, loosely cymose, yellow; bractlets much shorter than the lanceolate acuminate calyx-lobes; petals obovate, emarginate, exceeding the calyx-lobes; stamens about 20; achenes glabrous.
Prairies, western Minnesota to Saskatchewan, Alberta, Nebraska and New Mexico. Summer.
P. Hippiana Lehm. Nov. Stirp. Pug. 2: 7. 1830. Potentilla leucophylla Torr. Ann. N. Y. Lyc. 2: 197. 1825. Not Pall. 1773.
Erect or ascending, perennial, branched above, rather stout, 1°-2 1/2° high, densely floccose as well as silky. Stipules lanceolate, acuminate, entire; lower and basal leaves petioled, pinnately 5-11-foliolate; leaflets oblanceolate or oblong, obtuse, narrowed or cuneate at the base, 6"-18" long, incisely dentate, very white beneath, the lower ones smaller than the upper, and no smaller ones interspersed; flowers terminal, yellow, loosely cymose, 3"-6" broad; petals obovate, retuse, a little exceeding the lanceolate acute calyx-lobes and slightly narrower bractlets; stamens about 20; style filiform; achenes glabrous.
Dry soil, northwestern Minnesota and Assiniboia to British Columbia, south to New Mexico and Arizona. June-Aug.