322 NORTH AMERICAN FLORA [VoLruME 22 
long; leaflets broadly obovate, obtuse, coarsely crenate, green and sparingly hairy above, 
white-tomentose beneath, 0.5-3 cm. long; stem-leaves mostly 3-foliolate, small, short-peti- 
oled, with broadly lanceolate stipules; cymes open but few-flowered ; hypanthium and calyx 
densely silky ; bractlets and sepals lanceolate, subequal, about 5 mm: long; petals obcordate, 
yellow, about 8 mm. long, nearly twice as long as the sepals; stamens about 20; pistils. 
many; styles filiform. 
TYPE LocaLity : [Sierra de Pachuca, Hidalgo,] Mexico. 
DISTRIBUTION : Mountains of Central Mexico. 
71. Potentilla leptopetala Lehm. Delect. Sem. Hort. Hamb. 
1830: 8. 1830. 
? Potentilla hiemalis Schlecht. Linnaea 5: 572. 1830. 
Potentilla frigida Schiede & Deppe; Lehm. Stirp. Pug. 9: 59, asasynonym. 1851. 
Stem ascending, 1-2-leaved, covered with long grayish spreading hairs; basal leaves. 
digitately 5-foliolate, pilose or glabrate and green above, white-tomentose and silky with 
long spreading hairs beneath; leaflets ovate, strongly nerved, evenly crenate, with ovate 
obtusish teeth ; stem-leaves 3-foliolate; stipules ovate, acuminate, entire; bractlets lanceo- 
late, much shorter than the ovate sepals; petals obcordate, scarcely equaling the sepals, 
slightly emarginate; stamens about 20; pistils many. 
TYPE LOCALITY: High places between Mexico and Tolucca, Mexico. 
DISTRIBUTION: Central Mexico. 
ILLUSTRATION: Lehm. Rev. Potent. AJ. 47. 
XVII. Horridae. Perennial plants with thick short caudices, covered by the thick 
leathery leaf-bases. Basal leaves digitately 5-7-foliolate, with linear-oblong or linear-oblan- 
ceolate, crenate, thick leaflets, which are tomentose beneath; stem-leaves much reduced. 
Flowers rather small in dense cymes. Petals yellow, obcordate. Styles filiform. 
72. Potentilla horrida Rydb. Bull. Torrey Club 28: 173. 1901. 
Perennial, with very thick woody root and a short caudex covered with the thick 
coriaceous brown remains of old leaves ; stems ascending, 1.5-4 dm. high, stout, few-leaved, 
hirsute-villous ; petioles of the basal leaves 5-10 cm. long, stout, densely hirsute-villous, 
broadened at the base and surrounding the stem ; leaves digitate; leaflets usually 5, linear- 
oblong or oblong-lanceolate, obtuse, crenulate, 3-5 cm. long, 7-12 mm. wide, densely pu- 
bescent on both sides, almost velvety ; pubescence at first white, later brown, consisting 
of tomentum and longer silky hairs; stem-leaves similar or trifoliolate, much smaller; the 
upper subsessile ; the stipules lanceolate to linear-subulate, 1-3 cm. long, adnate to the. 
petioles ; cyme rather congested ; hypanthium and calyx densely pilose ; bractlets lanceolate, 
acute, about half as long as the ovate-lanceolate sepals, which are about 5 mm. long; petatls. 
yellow, broadly obovate, about 7 mm. long. ‘ 
TYPE LOCALITY: Sierra Madre, near Colonia Garcia, Chihuahua. 
DISTRIBUTION : Known only from the type locality. 
73. Potentilla durangensis Rydberg, sp. nov. 
Perennial, with a thick woody short caudex; stems erect, about 3 dm. high, pilose,, 
with long, yellowish, reflexed or divaricate hairs and glandular-atomiferous ; basal leaves: 
numerous, digitately 5-7-foliolate; petioles 6-12 cm. long, pilose and glandular-atom-- 
iferous, their bases thick, brown and leathery ; stipules adnate, free portion linear-lanceo-- 
late, attenuate, about 1 cm. long; leaflets linear-oblong or linear-oblanceolate, crenate, 
2-4 cm. long, 5-10 mm. wide, rounded at the apex, acute at the base, green, pilose, and glan- 
dular-atomiferous above, more or less tomentulose beneath ; lower stem-leaves similar but 
smaller, the upper ones subsessile and 3-foliolate; cyme rather dense; hypanthium and 
calyx pilose and atomiferous; bractlets linear-oblong, obtuse, 4 mm. long; sepals ovate, 
acute, about 6 mm. long; petals bright-yellow, broadly obovate, emarginate, about 7 mm. 
long; pistils many; styles filiform; stamens about 20. 
ei Type, mma at Quebrada Honda, Durango, May 20, 1906, Edward Palmer 223 (herb. N. Y.. 
ot. Gard.). 
