both sides; stipules broadly ovate and acuminate, 1-2 cm. long, deeply toothed; 

 cyme very dense and leafy, usually soon flat-topped; flowers with short hirsute 

 pedicels, less than 5 mm. in diameter; hypanthium sparingly hirsute and finely 

 pubescent, in age about 5 mm. in diameter; bractlets oblong, acute, about 3 mm. 

 long or nearly as long as the ovate acute sepals but much narrower; petals pale- 

 yellow, obovate, scarcely half as long as sepals; stamens seldom more than 5; 

 pistils numerous; styles terminal, short-fusiform, glandular below; achenes smooth, 

 brownish. 



In wet soil on edge of lakes and ponds, sandy bottomlands and moist prairies 

 in n.-cen. Okla. (Kay Co.), May-Aug.; Minn, and Alta. s. to Ark. and Okla. 



5. Potentilla biennis Greene. 



Annual or biennial with a slender taproot and usually a simple branched caudex, 

 pubescent with a mixture of fine slender spreading to somewhat appressed or 

 tomentose hairs and thicker multicellular glandular hairs; stems mostly single, 

 ascending to erect, 1-6 dm. tall, the usually numerous branches strongly ascending 

 and terminating in leafy-bracteate many flowered rather open cymes; leaves mostly 

 cauline, reduced upward, with well-developed oblong-lanceolate usually entire 

 stipules and 3 to 5 rotund-obovate to oblanceolate coarsely crenate-serrate leaflets 

 1-4 cm. long; calyx glandular-puberulent and often appressed-hirsute, shallowly 

 cupshaped, 5-8 mm. broad at anthesis, considerably accrescent in fruit; sepals 

 erect, ovate-triangular, much longer than the hypanthium; petals yellow, cuneate- 

 obovate, about half as long as the sepals; stamens usually either 10 or 15; pistils 

 numerous, the style basally thickened and terminal; achenes yellow, about 0.8 mm. 

 long, smooth. 



Waste places, along roadsides, and especially in sandy soil along streams, ponds, 

 lakes and in wet meadows, in Ariz. (Coconino Co.), May-Aug.; Sask. to B. C, 

 s. to. n. Ariz, and Baja Calif. 



6. Potentilla rivalis Nutt. Brook cinquefoil. Fig. 494. 



Annual or biennial, rather slender, freely branched, ascending to erect, to 5 dm. 

 high, softly villous, with paniculate-cymose very leafy flowering summit and 

 branches; lower leaves pinnate, with 2 or 3 closely approximate pairs of leaflets or 

 a single pair with the terminal leaflet 3-parted; cauline leaves with 3 or 5 leaflets; 

 leaflets cuneate-obovate to -oblong, 2-5 cm. long, usually blunt, strongly toothed; 

 flowers 4-8 mm. broad; mature calyx 5-8 mm. high, pilose; petals tiny, cuneate; 

 stamens 5 to 20; achenes smooth. 



In wet situations about lakes and ponds, along streams, in swamps and ditches 

 in the Tex. Panhandle, N. M. (Colfax, Grant, San Miguel and Santa Fe cos.) and 

 Ariz. (Coconino, Yavapai and Pinal cos.), May-July; from Man. to B. C, s. to 

 Mo., Kan., Tex., Mex. and Calif. 



7. Potentilla paradoxa Nutt. Fig. 494. 



Annual, biennial or shortlived perennial, superficially resembling P. rivalis, 

 somewhat villous, to about 4 dm. high; stems diffusely branched, decumbent or 

 ascending, slender or stout, leafy; leaves all pinnate, oblong to oblong-obovate; 

 leaflets in 2 to 5 distinct pairs, oblong to cuneate-obovate, sparsely crenate-dentate, 

 to about 3 cm. long, usually much smaller; cyme open-paniculate, leafy; flowers 

 yellow, on erect stalks, 5-7 mm. wide, the segments and bractlets subequal; stamens 

 about 20; achenes longitudinally ribbed, with a prominent corky protuberance 

 along the ventral suture. 



Moist or wet soil on river banks and lake margins in the Tex. Panhandle and 

 N. M. (Dona Ana, Mora, Santa Fe and Taos cos.), May-July; from Ont. to B. C, 

 s. to La., Tex. and N. M. 



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