MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 95 



Stem generally erect and strict, rather low, 1-2 dm. high, glabrate or sparingly pu- 

 berulent. Stipules ovate, pectinately toothed. Leaves pinnate, of 2-5 rather approximate 

 pairs of leaflets, glabrate or slightly puberulent ; leaflets obovate to oblanceolate, the lower 

 ones smaller, very deeply dissected into oblong acute or obtuse segments. Cyme rather 

 few-flowered. Hypanthium hirsute or puberulent ; bractlets narrowly ovate, somewhat 

 shorter than the broadly ovate sepals, both rather strongly veined. Petals obovate, about 

 equalling the sepals. Stamens 20. Pistils very numerous ; style short, fusiform. 



It is somewhat intermediate between P. Pennsylvavica and P. litoralis, resembling 

 the former in the erect habit, and in the form of the leaflets and their segments, and the 

 latter in the more approximate and fewer leaflets, the sparse pubescence and the strongly 

 nerved sepals. It is a high mountain plant, its range extending from British America 

 to Nevada. 



Assiniboia and Alberta: John Macoun, 1880 and 1885. 



Saskatchewan: John Macoun, No. 12567, 1896 ; Drummond. 



Montana: J. W. Blankinship, No. 62, 1890 (in part). 



Nevada: S. Watson, No. 326, 1868 (in part). 



77. Potentilla atrovirens. 



Stem stout, 2-3 dm. high, branched, with erect branches, dark colored, densely 

 pilose. Leaves very dark green, densely pilose on both sides, strongly veined, pinnate 

 with 3-4 pairs of leaflets, these obovate to oblanceolate, coarsely dissected about half way 

 to the midrib into oblong segments. Cyme narrow, many-flowered, with erect branches. 

 Hypanthium densely pilose, about 8 mm. in diameter when fully developed. Sepals and 

 bractlets subequal, ovate, exceeded by the cuneate-obovate bright yellow petals. Stamens 

 about 20, short. Pistils very numerous ; style short, fusiform. 



It much resembles some forms of P. Pennsylvanica, but differs in the dark color of 

 the plant, the erect branches of the cyme, the longer petals and the different pubescence, 

 It is a rare plant and only a few specimens are known. 



Wyoming : Aven Nelson, No. 2017a, 1896 (Douglas Creek, type). 



South Dakota: P. A. Rydberg, No. 667, 1892, in part. 



Minnesota: B. C. Taylor, No. 375, 1891 ; Max Menzel. 



78. Potentilla Pennsylvanica L. 



Potentilla Pennsylvanica L. Mant. PL 76. 1867. 



Ait. Hort. Kew. 2: 214; Ed. 2, 3: 275; Willd. Sp. PI. 2: 1099; Persoon, Syn. PI. 

 2 ; 54 ; Nestler, Mon. Pot. 24 and 36 ; Lehm. Mon. Pot. 21 and 55 ; Sprengel, Syst. 



