214 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



Potentilla Pennsylvanica L. Mant. 76 [Torr. & Gray, Fl. N. Am. 



i: 438; Man. R. M. 84; 111. Fl. 2: 214; R3'db. Mon. 95]. 



A plant belonging to the Great Plains, ascending in the more 

 open valleys to an altitude of 2000 m. 



Montana: Spanish Basin, 1896, Flodman, ^^2; Cottonwood 

 Creek, 5 jj ; Cliff Lake, July 27, 1897, Rydberg & Bessey, 4402; 

 Alhambra, 1892, F. D. Kclsey. 



* Potentilla Pennsylvanica arachnoidea Lehm. Stirp. Pug. 9: 41 



[Rydb. Mon. 98 J . 



This resembles var. strigosa^ but has a finer pubescence and 

 lacks the long hirsute hairs of that variety. It is a plant con- 

 fined to the mountain regions, growing on hillsides and in valleys, 

 at an altitude of 1500-2500 m. The variet}' stn'gosa is probably found 

 in the eastern parts of the State, but I have seen no specimens. 



Montana: Dear Lodge, i8g>), Fydderg, 268p; Spanish Basin, 

 1896, FJudman, jj^; Pony Mts., July 6, 1S97, Rydberg & Bessey, 

 4400; Spanish Basin, July i, 4401; Beaver Head Co., 1888, 

 TzL'Ccdy, 44. 



Potentilla glabrella Rydb. Mem. Dept. Bot. Columbia Univ. 2 : 94 ; 

 Potentilla Pennsylvanica glabrata Wats. Proc. Am. Acad. 8 : 554 

 [Man. R. M. 84] ; not P. glabrata Lehm. 

 In the mountains, on dr}' soil. 

 Montana: 1890,,/. W. Blankcns/iip, 62. 



* Potentilla bipinnatifida Dougl. ; Hook. Fl. Bor. Am. i: 188 



[Rydb. Mon. 99] . P. Pciinsxlvanica bipinnatifda Torr. & Gray, 



FI.'n. Am. I : 438. 



Resembles somewhat P. Pc.insxlvanica and has about the same 

 distribution, but differs in the very narrowly linear segments of the 

 leaves, which are silvery white, especially beneath. 



Montana: Cottonwood Creek, i8<^6, Flodnian, 555; Sheridan, 

 1892, Mrs. Fitch. 



* Potentilla pinnatisecta (Wats.) Aven Nelson, Bull. Wyo. Agric. 



Exp. Sta. 28 : 104 [Rydb. Mon. 106] ; Potentilla diversifolia 



pinnatisecta Wats. King's Exp. 5: 87. 



A near relative of P. Plattensis, but differing in the erect flowering 

 stems and the more numerous and coarser hairy leaves. P. Plattensis 

 is a native of the valleys south of our range, while P. pinnatisecta 

 is an alpine plant, growing at an altitude of 2500-3200 m. 



