256 ROSACEAE (rose EAMILY) 



Vn. RUBRICAULES. — Low caespitose perennials; leaves S-7- 

 foliolate; styles filiform. 



Calyx bractlets elliptic, obtiise 27. P. saxUnontaiuu 



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



VUI. MtJLTIJUGAE. — Low caespitose perennials; leaves pinnately 

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

 Stems from tne crown of 'a taproot. 



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



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



Stems ftoxa a multicipital woody caudex. 



Leaflets many, cleft to the base into hnear divisions. 

 Whitish, siiky-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 or less tomen- 

 tose;- style filiform^ . 

 Leaves rWhite-tomentbse, 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. FI. N. A. 1: 437. 1840. At first 

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

 roliolate, 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-foholate; the upper trifoUolate and reduced 

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

 larger than the lateral leaflets; 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 swelhng on the inner side. P. supina in part. — !^tem 

 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 trifoUolate, 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. rivtdis miUe- 

 grana. — From Illinois to California. 



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

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

 trifoUolate; leaflets cuneate-flabelTiform, incisely lobed or with broad mucronu- 

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

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

 carpels whitish. (P. kUeriflora Rydb. 1. c. 44.)— ^From Canada to Mexico and 

 California. 



6. Potentilla monspeUensis L. Sp. PL 499. 1753. Stems stout, erect or 

 spreading, leafy, branched above, hirsute: leaves digitately 3-foUolate, 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 



