116 MEMOIRS FROM THE DEPARTMENT OF BOTANY OP COLUMBIA UNIVERSITY 



entire or incised. Leaves with short petioles, densely white silky-villous ; leaflets 

 crowded and often somewhat verticillate, about 1 cm. long, broadly cuneate and deeply 

 cut-toothed. Inflorescence dense in the typical form ; flowers 1.5 cm. in diameter. Hy- 

 panthium silky-villous; bractlets oblong, generally much shorter than the triangular- 

 ovate acute sepals. Petals obcordate, 6-10 mm. long, exceeding the calyx. 



Potcntilla Breweri much resembles P. Plaffensis. It has the large stipules character- 

 istic of that species and also essentially the same flowers. The leaflets are, however, 

 broader and less divided and densely silky-villous. In the typical form the cyme is 

 rather dense and the flowers larger. 



CaJifonun: Bolander, No. 5084, 1866; 1872; W. H. Brewer, Nos. 1708 and 1720, 

 1863; Bolander & Kellogg, 1872; Baker A Nutting, 1894; Brandegee, 1892; A. Kellogg, 

 1876 ; J. W. Congdon, 1890. 



Potentilla Breweri expansa Wats. 



Potentilla Breweri expansa Wats. Bot. Cal. 1 : 179. 1876. 



E-ydb. Bull. Torr. Bot. Club, 24 : 1. 



Potentilla Plattensis leucophylla Greene, Erythea, 1 : 4. 1893. 



Illustrations : Plate 52, f. 1; dissection of flower,/. 2; pistil,/. 3; stamen,/. 4; 

 fruiting hypanthium and calyx, /. 5. 



Stems slender, decumbent or ascending; flowers smaller, on slender pedicels; leaves 

 less villous, especially above; petals about 5 mm. long. 



This resembles P. Plaffensis still more, having the open cyme of that species. It 

 is apparently more common than the species. 



California. J. G. Lemmon, Nos. 04 and 712, 1874; No. 85, 1875; C. F. Sonne, 

 No. 351, 1888; 1892 (P. Plaffensis leveoplnjlla Greene); Coville & Funston, Nos. 1750, 

 1531 and 2117, 1891; M. E. Jones, No. 351A, 1881. 



Nevada: S. Watson, No. 332, 1868 (in part). 



103. Potentilla ambigens Greene. 



Prjfenfilla ambigens Greene, Erythea, 1 : 4. 1893. 



Rydb. Bull. Torr. Bot. Club, 24: 3. 1897. 



Illustrations: Plate .J.i,/i; dissection of flower, / ^; pistil,/.?; stamens, / .4-5; 

 fruiting hypanthium and calyx, f. 6. 



Stem stout, 6-7 dm. high, more or less striate, densely silky-villous with long 

 spreading hairs, branched above. Stipules large, those of the basal leaves ovate-oblong, 

 subentire, 2-4 cm. long, more or less membranous and brownish, those of the stem 



