108 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 



YeUo>r,trmc iXat Park: F. Tweedy, No. 470; F. H. Burglehaus, 1893. 



Alberta: John Macoun, Nos. 10488, 10489 and 10493, 1895; ITus. 4 and 15, 189/. 



Asshnhoia: John Macoun, Nos. 10483 and 10484, 1895. 



93. Potentilla Plattensis Nutt. 



I'okutma Plattensis Nutt.; Torr. & Gray, Fl. N. Am. 1 : 439. 1840. 



Dietr. Syn. Pi. 3: 187; Walp. Rep. 2: 32; Ann. 2: 472; Lehm. Rev. Pot. 28. 



Gray. Proc. Acad. Phil. 1863: 64; AVats. Proc. Am. Acad. 8: 556;' Brewer & 

 AVats. Bot. Cal. 1: 179; Porter ct Coult. ^yn. 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, (Jont. U. S. Nat. Herb. 4: 96; Rydb. Bull. Torr. 

 Bot. Club, 23; 432. 



Macoun, Cat. Can. PI. 138 and 517.^ 



Illustratioxs : Lehm. Rev. Pot. pi. 6. Plate, 46, f. 6 ; dissection of flower, /. 7; 

 pistil, /. 8; stamen, /. 9 ; fruiting hypanthium and calyx, /. 10 ; basal leaf of the narrow 

 leaved form, f. 11. 



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 leaves many, pinnate ; 

 leaflets 4-8 pairs, light green in color, appressed-strigose or glabrate, obovate-oblong 

 in outline, deeply pinnatifid with oblong obtuse IoIjcs, about .5 cm. long in the typical 

 form, but in the more common form with nearly linear more acutish lobes, often 

 three-quarters cm. L mg. 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 refuse, longer than the sepals. 



The type specimens of Nuttall have light green leaves with 4-8 pairs of oblong- 

 cuneate leaflets, dissected j.nto broadly oblong obtuse segments .5 cm. long, the stem 

 more or less ascending. In the more common form, however, the segments are 

 often .75 cm. 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. rinffen.sis 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. 



■ Includes P. pinnaUseda. 



