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. 
Potentilla millegrana Eng.; Lehm. Ind. Sem. Hort. Bot. Hamb. 1849: 11, 1849. 
Not Dougl. 
Lehm. Stirp. Pug. 9: 22; Rev. Pot. 202; Walp. Amn. 2-517, 
Wats. King’s Rep. 5: 85; Porter, U. 5. Geol. Surv. 1871: 481; Greene, FI. 
Fran. 1: 65; Man. Bay Reg. 115; Rydb. Bull. Torr. Bot. Club, 23: 260; PL. Neb: 
2 AT 
Potentilla rivalis var. millegrana Wats. Proc. Am. Acad. 8: 5bos USTs: 
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. Pl. 136 and 516. 
Potentilla Nicolletii Sheld. Bull. Geol. and Nat. Hist. Surv. Minn. 7: 16 (in part). 
1894. Not P. supina var. Nicolletii Wats. 1875. 
Potentilla leucocarpa Rydberg, in Britton & Brown, HL FL. 2: DAD SOM 
ILLustRAtions: Britton & Brown, Ill. Fl. 2: f 1924. Pare 8, f. 1; dissection of 
flower, f. 2; pistil, f. 3; stamen, f. 4; fruiting hypanthium and calyx, f. 5. 
Stem slender and branched throughout, 4-8 em. high, divaricate, softly pubescent, 
sometimes nearly glabrous. Stipules lanceolate or oval, generally subentire, acute, 3-10 
mm. long. Leaves ternate, finely pubescent, venerally somewhat pale and thin, the lower 
petioles 3-8 em. 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; style 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. lewcocarpa all the leaves are, 
asarule, ternate. The plant is much branched, with divergent branches and in the 
typical form spreading. his 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. 
