256 ROSACEAE (ROSE FAMILY) 



VII. RUBRICAULES. Low caespitose perennials; leaves 5-7- 

 foliolate; styles filiform. 



Calyx bractlets elliptic, obtuse 27. P. saximontana. 



Calyx bractlets linear-oblong, acute ...... 28. P. rubricaulis. 



VIII. MULTIJUGAE. Low caespitose perennials; leaves pinnately 

 9-27-folioiate; styles filiform; no tomentum. 



Stems from tae crown of a taproot. 



Prostrate-spreading; leaflets not cleft to the midrib . . 29. P. plattensis. 

 Erect; leaflets cleft to the midrib . . ' . . . . 30. P. pinnatisecta. 

 Stems from a multicipital woody caudex. 



Leaflets many, cleft to the base into linear divisions. 



Whitish, silky-strigose; petals elliptic, rounded at apex . 31. P. monidensis. 



Somewhat hirsute; petals obovate and truncate-retuse . 32. P. wyomingensis. 

 Leaflets few, oblong, incisely few-toothed. 



Green and glabrate on both sides 33. P. rupicola. 



Silky below, the teeth crenate 34. P. crinita. 



IX. LEUCOPHYLLAE. Stout perennials; leaves pinnately 7-13- 

 foliolate; leaflets silvery-silky and usually more orlesstomen- 

 tose; style filiform. 



Leaves white-tomentose, especially beneath. 



Tomentose on both sides; bractlets shorter than the sepals . 35. P. effusa. 



Silky above, tomentose-silky beneath; bractlets as long as the 



sepals ......... 36. P. Hippiana. 



Leaves silvery-silky, scarcely tomentose, greener above . . 37. P. ambigens. , 



1. Potentilla paradoxa Nutt. T. & G. Fl. N. A. 1: 437. 1840. At first 

 subsimple, later freely branched and more spreading: leaves pinnately 7-11- 

 foliolate, short-petioled, sparingly short-hirsute, becoming glabrate; leaflets 

 obovate-cuneate, with crenately rounded teeth; stipules ovate, acute, more or 

 less toothed and ciliate: sepals and petals subequal: achenes with a thick 

 corky swelling on the inner side. P. supina in part. Throughout our range 

 and across the continent to the northward. 



2. Potentilla Nicollettii (Wats.) Sheld. Bull. Nat. Hist. Surv. Minn. 9: 16. 

 1894. Stems slender, spreading or prostrate and freely branched: leaves thin- 

 hirsute; the lower pinnately few-foliolate; the upper trifoliolate and reduced 

 in size; leaflets obovate-cuneate, with acutish teeth; the terminal one much 

 larger than the lateral leafltets; stipules ovate, acute, entire or sinuate: flowers 

 falsely racemose, on slender pedicels in the axils of the uppermost leaves: 

 bracts and sepals subequal, mucronate, as long as the obovate-cuneate petals: 

 achenes with a corky swelling on the inner side. P. supina in part. Eastern 

 Wyoming to Minnesota. 



3. Potentilla rivalis Nutt. T. & G. Fl. N. A. 1: 437. 1840. Stems erect, 

 simple below, branched above, villous-hirsute : leaves all ternate or the lower 

 pinnately 5-foliolate, somewhat villous or glabrate; leaflets obovate, incisely 

 serrate; stipules broadly ovate, coarsely toothed: flowers short-pediceled, in 

 a leafy cyme with ascending branches: sepals exceeding the bracts and also 

 the small cuneate petals: stamens 10: achenes numerous, not gibbous. From 

 Canada to Mexico. 



4. Potentilla leucocarpa Rydb. (Monog. Pot.) Mem. Dept. Bot. Columbia 

 Univ. 2: 43. 1898. Stem freely and divaricately branched throughout: all 

 the leaves trifoliolate, finely pubescent, thin and pale; leaflets serrate, oblong- 

 cuneate; stipules lanceolate, subentire: flowers in broad spreading leafy- 

 bracteate cymes: bracts and sepals subequal, exceeding the small light yellow 

 petals: stamens 10: carpels numerous, whitish, and smooth. P. rivalis mille- 

 grana. From Illinois to California. 



5. Potentilla biennis Greene, Fl. Fran. 1: 65. 1891. Branched from the 

 base, erect, stoutish, 2-3 dm. high: leaves pubescent and granulo-glandular, 

 trifoliolate; leaflets cuneate-flabelliform, incisely lobed or with broad mucronu- 

 late teeth; stipules oblong-lanceolate, entire or lobed: flowers in dense cymes: 

 sepals longer than the bracts and the small obovate-cuneate petals: stamens 10: . 

 carpels whitish. (P. lateriflora Rydb. 1. c. 44.) From Canada to Mexico and v 

 California. 



6. Potentilla monspeliensis L. Sp. PI. 499. 1753. Stems stout, erect or 

 spreading, leafy, branched above, hirsute: leaves digitately 3-foliolate, more or 

 less hirsute; leaflets obovate, serrate with broad teeth; stipules broadly ovate, 

 more or less toothed: flowers on short pedicels in a dense leafy cyme: calyx 



