ROSACE A E. 5O5 



n. Potentilla leucocarpa Rydb. DIFFUSE CINQUEFOIL. (I. F. f. 1924.) 

 Decumbent or ascending, annual, usually diffusely branched, 4-8 dm. high, softly 

 villous-pubescent, or glabrate. Leaves all but the uppermost petioled, 3-foliolate; 

 leaflets oblong, cuneate, thin, flaccid, pubescent, deeply serrate, 2-4 cm. long; 

 flowers loosely cymose, 3-4 mm. broad; calyx-lobes ovate, acute, exceeding the 

 obovate petals; stamens about 10; style slightly thickened below. In damp soil, 

 111. to Minn., N. Mex., Gal. and Wash. May-Sept. 



Potentilla rivilis Nutt., a western species which may reach our limits, is distin- 

 guished from this by its usually pinnately 5-foliolate lower leaves, viscid pubescence, 

 stricter erect habit, and more numerous stamens. It has been collected at the stockyards 

 of Chicago. 



12 Potentilla paradoxa Nutt. BUSHY CINQUEFOIL. (I. F. f. 1925.) 

 Softly pubescent, annual or biennial, rather stout, bushy, 3-8 dm. high. Leaves 

 all but the uppermost petioled, pinnately 7-ii-foliolate; leaflets obovate or oval, 

 obtuse, I5--25 mm. long, sparingly pubescent, crenate, the upper ones commonly 

 confluent or decurrent on the rachis; flowers terminal, loosely cymose, leafy - 

 bracted, 7 mm. broad; petals obovate, cuneate, about equalling the ovate calyx - 

 lol>es; stamens about 2O; style terminal, thickened below. Shores and river banks, 

 N. V. and Out. to Ore. and N. Mex. Also in Mex. and Mantchuria. June-Sept. 



13. Potentilla Nicolletii (S. Wats.) Sheldon. NICOLLET'S CINQUEFOIL. 

 (I. F. f. 1926.) Similar to P. paradoxa, but more spreading and more branched; 

 lower leaves only pinnate, with few leaflets; upper leaves 3-foliolate; teeth of the 

 leaflets acute; inflorescence elongated, falsely racemose; stamens 10-15. N. Dak., 

 Iowa and Mo. 



14. Potentilla Hippiana Lehm. WOOLLY CINQUEFOIL. (I. F. f. 1927.) 

 Perennial, 3-5 dm. high, densely floccose as well as silky. Lower and basal leaves 

 petioled, pinnately 5-ii-foliolate; leaflets oblanceolate or oblong, obtuse, 2-5 cm. 

 long, deeply toothed, very white beneath, the lower ones smaller than the upper; 

 flowers loosely cymose, 7-10 mm. broad; petals obovate, retuse, a little exceeding 

 the lanceolate acute calyx-lobes; stamens about 20. Dry soil, Minn, and Assin. to 

 Br. Col., Neb. and N. Mex. June- Aug. 



15. Potentilla effusa Dougl. BRANCHED CINQUEFOIL. (I. F. f. 1928.) 

 Closely related to P. Hippiana. Plant 2-4 dm high, diffusely branched above ; 

 leaves sometimes interruptedly pinnate, tomentose-canescent, but not silky; leaf- 

 lets 5-11, cuneate-oblong, obtuse; flowers 6-8 mm. broad, loosely cymose; bract- 

 lets shorter than the lanceolate acute calyx-lobes; petals obovate, emarginate, ex- 

 ceeding the calyx-lobes; stamens about 20. Prairies, Minn, (according tOjUpham) 

 to Mont, and Colo. Summer. 



1 6. Potentilla bipinnatifida Dougl. CUT-LEAVED CINQUEFOIL. Stems 

 erect or ascending, simple, white silky-villous, 3-5 dm. high. Basal leaves pin- 

 nately 7-9-foliolate; stem-leaves subsessile and often subdigitate; leaflets approxi- 

 mate, obovate in outline, pectinately divided into linear obtuse segments, silvery 

 white; flowers densely cymose; sepals ovate, longer than the lanceolate bractlets 

 and about equalling the obovate-cuneate, truncate petals. Prairies, Hudson Bay 

 to Sask., Alb. and Colo. [P. Pennsylvanica bipinnatifida T. & G.] 



17. Potentilla atrovirens Rydb. DARK-GREEN CINQUEFOIL. Stem stout, 

 2-3 dm. high, branched, with erect branches, dark green, densely pilose. Leaves 

 similar to those of P. Pennsylvanica, but dark green, densely pilose and strongly 

 veined; cyme many-flowered, narrow, with erect branches ; bractlets and sepals 

 ovate, subequal, exceeding the cuneate-obovate bright yellow petals. Prairies, 

 Minn., S. Dak. and Wyo. 



1 8. Potentilla Pennsylvanica L. PRAIRIE CINQUEFOIL. (I. F. f. 1929.) 

 Stem 4-8 dm. high, tomentose. Leaves pinnately 5-1 5-foliolate, grayish-tomentose 

 beneath, glabrous above ; leaflets oblong or oblanceolate, cleft halfway to the mid- 

 rib into oblong lobes, margins scarcely revolute ; cymes dense; petals yellow, 

 obovate, truncate or slightly emarginate, about equalling the ovate triangular 

 acute sepals and the lanceolate bractlets ; style thickened below. On prairies, 

 Hudson Bay to the Canadian Rocky Mountains, south to N. Mex. Summer. 



Potentilla Pennsylvania strigbsa Pursh. Stem usually lower ; pubescent with long 

 villous hairs: leaflets with deep narrow divisions, margins revolute. Manitoba and the 

 N. W. Terr, to Kans. and N. Mex. Also in Siberia. 



