344 NORTH AMERICAN FLORA LVoLUME 22 
in outline, deeply pinnatifid with oblong obtuse lobes, about 5 mm. long in the typical 
form, but in the more common form with nearly linear more acutish lobes, often 8 mm. 
long; stem-leaves reduced, the uppermost only 3-cleft; flowers in few-flowered, rather 
open cymes, about 1 cm. in diameter; pedicels in fruit arcuate-spreading ; hypanthium 
strigose ; sepals and bractlets lanceolate, long-acuminate, the latter about one half the size 
of the sepals, which are 3-4 mm, long; petals yellow, obovate, slightly retuse, longer than 
the sepals; stamens 20; pistils many; styles filiform. 
TYPE LOCALITY: Plains of the Platte. 
DISTRIBUTION: Valleys, from New Mexico and Utah to Saskatchewan. 
f6 Py aa Lehm. Rev. Potent. p/. 6,7. 2; Mem. Dep. Bot. Columbia Univ. 2: pl. 4, 
149. Potentilla arizonica Greene, Pittonia 1: 104. 1887. 
Ivesia pinnatifida S. Wats. Proc. Am. Acad. 20: 364. 1885. Not P. pinnatifida L. 1753. 
Perennial, with a thick woody branched caudex; stems ascending or erect, a little 
over 1 dm. high, subscapose, grayish-strigose; leaves nearly all basal, rather irregularly 
pinnate, with 15-25 leaflets, grayish strigose-hirsute; leaflets obovate in’ outline, 
divided to near the midrib into 7-9 linear diverging segments; stipules brown, adnate to 
the petiole for a long distance, striate; cyme 5-8-flowered; hypanthium strigose, in fruit 
5-8 mm. in diameter; bractlets oblong or lanceolate, a little shorter than the ovate sepals ; 
petals unknown ; stamens 20; pistils many; styles filiform. 
TYPE LOCALITY: Meadows near Flagstaff, Arizona. 
DISTRIBUTION : Known only from the type locality. 
ILLUSTRATION : Mem. Dep. Bot. Columbia Univ. 2: £1. 4, f. 2-5. 
150. Potentilla versicolor Rydberg, sp. nov. 
Perennial, with a thick caudex; stems about 2 dm. long, decumbent or ascending, 
sparingly appressed-silky; basal leaves 5-10 cm. long, white-silky and tomentose when 
young, more green in age, pinnate, with 15-25 leaflets, which are 5-8 mm. long, 
cuneate or flabelliform in outline, divided to near the base into 3-7 linear-oblong acutish 
divisions; stem-leaves few, small, with few leaflets; stipules lanceolate, entire; inflores- 
cence 3-6-flowered, open ; bractlets elliptic or oval, often obtuse, 3 mm. long; sepals lance- 
olate, acute, 5 mm..long; bypanthium and calyx silky with somewhat spreading hairs; 
petals yellow, rounded-obcordate, 5 mm. long; stamens about 20; pistils many; styles 
filiform. 
Type collected on Grayhart Buttes, Oregon, in 1896, Coville G’ Leiberg 307 (U.S. Nat. Herb. 
no. 275729). 
151. Potentilla Nelsoniana Rydberg, sp. nov. 
Potentilla pinnatisecta A. Nels. Wyo. Exp. Sta. Bull. 28: 104, in part, as to description. 1896. 
Not P. diversifolia pinnatisecta 8. Wats. 1871. 
Perennial, with a tap-root and short caudex; stamens erect or ascending, 1.5-3 dm. 
high, glabrous or sparingly strigose; basal leaves pinnate, with 9-15 leaflets, the earlier 
appressed-pubescent, the rest glabrate and more or less glaucous; petioles 1-4 cm. long, 
glabrous or nearly so; leaflets cuneate, 1-3.5 cm. long, the upper three pinnately cleft with 
5-7 lance-oblong divisions, the rest 2-3-cleft at the apex or some entire; stem-leaves small, 
3-7-foliolate, the upper sessile; stipules ovate, entire, 7-15 mm. long; cyme 10-25- 
flowered, with ascending branches ; hypanthium strigose, about 5mm. broad in fruit; bract- 
lets linear or lanceolate, 3 mm. long; sepals lance-ovate, 4-5 mm. long, acute; petals obo- 
vate, emarginate, 5-6 mm. long; stamens about 20; pistils many; styles filiform. 
Type collected near La Plata Mines, Wyoming, in 1895, Aven Nelson 1819 (herb. Columbia 
Univ.). 
DISTRIBUTION : Medicine Bow and Uintah Mountains of Wyoming and northern Utah. 
152. Potentilla decurrens (S. Wats.) Rydb. Bull. Torrey 
Club 23: 396: 1896. 
Potentilla dissecla decurrens S. Wats. Proc, Am. Acad. 8: 557. 1873. 
Perennial, with a short cespitose caudex; stems glabrous up to the inflorescence, less 
than 1 dm. high, ascending; basal leaves pinnate, with 11-13 leaflets, which are rather 
