108 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 
Yellowstone Nat. Park: F. Tweedy, No. 470; F. H. Burglehaus, 1893. 
Alberta: John Macoun, Nos. 10488, 10489 and 10493, 1895: Nos. 4 and Loe USOT: 
Assiniboia: John Macoun, Nos. 10483 and 10484, 1895. 
93. Potentilla Plattensis Nutt. 
Potentilla Plattensis Nutt.; Torr. & Gray, FL eN, Ame 3439.) 1840) 
Dietrisyn els: s87- Walp. Rep. 2: 32; Ann. 2: 472; Lehm: Rev. Pot. 28. 
Gray. Proc. Acad. Phil. 1863: 64: Wats. Proc. Am. Acad. 8: 556;' Brewer & 
Wats. Bot. Cal. 1: 179; Porter & Coult. Syn. Fl. Colo. 36; Rothrock, in Wheeler’s 
Exp. 6: 113; Coulter, Man. Rocky Mts. 85; Rattan, An. Key W. Coast Bot. 51; 
Greene, Fl. Fran. 1: 64; Coville, Cont. U. S. Nat. Herb. 4: 96: xydb. Bull. Torr. 
30t. Club, 23; 432. 
Macoun, Cat. Can. Pl. 138 and 517.1 
InLustRatIons: Lehm. Rev. Pot. pl. 6. Puan, 46, f. 6; dissection of flower, aes 
pistil, f. 8; stamen, f. 9; fruiting hypanthium and calyx, f. 10; basal leaf of the narrow 
leaved form, f. 71. 
Low, 1-2 dm. high, ascending or spreading, generally with numerous subsimple 
appressed-strigose stems from the caudex. Stipules very large for the size of the plant, 
about 1 cm. long, broadly ovate, subentire and often obtuse. Basal leayes many, pinnate ; 
leaflets 4-8 pairs, light green in color, appressed-strigose or glabrate, obovate-oblong 
in outline, deeply pinnatifid with oblong obtuse lobes, about .5 em. long in the typical 
form, but in the more common form with nearly linear more acutish lobes, often 
three-quarters em. long. Stem leaves reduced, the uppermost only 3-cleft. Flowers in 
few-flowered, rather open cymes, about 1 cm. in diameter. Hypanthium  strigose. 
Sepals and bractlets lanceolate, long-acuminate, the latter about one-half the size of the: 
sepals. Petals yellow, obovate, slightly retuse, longer than the sepals. 
The type specimens of Nuttall have light green leaves with 4-8 pairs of oblong- 
cuneate leaflets, dissected into broadly oblong obtuse segments .5 cm. long, the stem 
more or less ascending. In the more common form, however, the segments are 
often .75 em. long, nearly linear and often acute (Plate 46, f. 11), the stem more or less 
spreading and the flower-clusters very irregular. It may be a good variety. 
All forms of P. Plattensis are characterized by the stipules, which are unusually 
large for the size of the plant. Its range is from Colorado and Utah to the Saskatche- 
wan, but it belongs to the valleys of the high plains rather than to the alpine regions. 
1Includes P. pinnatisecta. 
