MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 43 



nate leaflets, has been collected by C. V. Piper on sandy banks of Snake River, at Al- 

 mota, Washington, in 1897. 



16. Potentilla leucocarpa Rydberg. 



PotentiUa millegrana Eng. ; Lehm. Ind. Sem. Hort. Bot. Hamb. 1849: 11, 1849. 

 Not Dougl. 



Lehm. Stirp. Pug. 9 : 22 ; Rev. Pot. 202; Walp. Ann. 2: 517. 



Wats. King's Rep. 5: 85; Porter, U. S. Geol. Surv. 1871: 481; Greene, Fl. 

 Fran. 1 : 65; Man. Bay Reg. 115; Rydb. Bull. Torr. Bot. Club, 23: 260; FI. Neb. 

 21: 17. 



PotentiUa rivalis var. millegrana Wats. Proc. Am. Acad. 8 : 553. 1873. 



Brewer and Wats. Bot. Cal. 1: 178; Porter & Coulter, Syn. Fl. Colo. 36, 1874; Coult. 

 Man. Rocky Mts. 84, 1885; Wats, and Coult. in Gray, Man. Ed. 6: 159. 



Macoun,.Cat. Can. PI. 136 and 516. 



Potentilla Nicolletii Sheld. Bull. Geol. and Nat. Hist. Surv. Minn. 7: 16 (in part). 

 1894. Not P. supina var. Nicolletii Wats. 1873. 



Potentilla leucocarpa Rydberg, in Britton & Brown, 111. Fl. 2 : 212. 1897. 



Illustrations: Britton & Brown, 111. FI. 2: /. 10.24.. Plate 8,f. 1; dissection of 

 flower,/. 2; pistil,/. 3; stamen,/. 4.; fruiting hypanthium and calyx, /'. 5. 



Stem slender and branched throughout, 4-8 cm. high, divaricate, softly pubescent, 

 sometimes nearly glabrous. Stipules lanceolate or oval, generally subentire, acute, 3-10 

 mm. long. Leaves ternate, finely pubescent, generally somewhat pale and thin, the lower 

 petioles 3-8 cm. long. Leaflets oblong-cuneate, deeply serrate. Cyme much branched, 

 leafy, but the leaves much reduced, spreading. Flowers 3-4 mm. in diameter on slender 

 pedicels. Hypanthium soft-pubescent, in fruit about 5 mm. in diameter. Bractlets and 

 sepals oblong-ovate, acute, about the same length, but the former a little narrower. Petals 

 oblong-cuneate, shorter than the sepals, light yellow. Stamens generally 10, with didy- 

 mous anthers. Pistils numerous ; st)de terminal, fusiform. Achenes smooth, light 

 colored, small. 



This, as well as P. pentandra, has been regarded as a variety of the preceding. I 

 think it is better, however, to consider them species. In P. leucocarpa all the leaves are, 

 as a rule, ternate. The plant is much branched, with divergent branches and in the 

 typical form spreading. This habit and the smaller, nearly white achenes separate it 

 from forms of P. rivalis with ternate leaves. The plant is generally also more glabrate. 

 It has a wide range, but is not a common plant. It extends from Illinois to New Mexico, 

 California and Washington. 



