308 NORTH AMERICAN FLORA [VoLuME 22 
long as the sepals; stamens seldom more than 5, very small, with didymous anthers; pistils 
exceedingly numerous; styles terminal, short-fusiform and glandular below; achenes 
smooth, brownish. 
TYPE LOCALITY: Fort Gibson, Arkansas. 
DISTRIBUTION : Bottom-land, especially in sandy soil, from Missouri and Arkansas to Saskat- 
cchewan, Alberta, and Nebraska. 
ILLUSTRATIONS: Lehm. Rev. Potent. p/. 62, f. 4; Britt. & Brown, Ill. Fl. /. 1923 ; Mem. Dep. 
Bot. Columbia Univ. 2: p/. 12. 
IV. Arenicolae. Plants originally described as annuals, but the root is evidently bien- 
nial or perennial. Flowers small, white; receptacle beset with bristles exceeding the 
ovaries in length; style long and slender, a little thickened and glandular near the base. 
Leaves pinnate with 11-21 dissected leaflets. 
20. Potentilla Newberryi A. Gray, Proc. Am. Acad. 6: 532. 1865. 
Ivesia gracilis A, Gray, in Newb. Pac. R. R. Rep. 63: 72. 1857, Not P. gractlis Dougl. 1829. 
Potentilla Newberryt arenicola Rydb. Mem. Dep. Bot. Columbia Univ. 2: 112. 1898. 
Stems 2-4 dm. high, erect or spreading in the variety, slightly silky-villous, leafy, 
but stem-leaves rather small; stipules linear; basal leaves pinnate, with 3-10 pairs of 
slightly silky-villous leaflets divided to near the base into 3-5 oblong-spatulate or linear 
segments; stem-leaves similar, but with 2-4 pairs of less divided leaflets; cyme diffuse, 
with slender pedicels, which are at last drooping, but not abruptly reflexed just below the 
hypanthium ; hypanthium villous, about 5 mm. in diameter; bractlets and sepals ovate- 
lanceolate, subequal, 4 mm. long; petals white, obcordate, exceeding the sepals; stamens 
20; pistils numerous; styles slender, but glandular and somewhat thickened below. 
TYPE LOCALITY: Banks of Rhett Lake [California or Oregon]. 
DISTRIBUTION: Washington to northern California. 
ILLUSTRATIONS: Pac. R. R. Rep. 63: pl. 11; Mem. Dep. Bot. Columbia Univ. 2: pl. 49; pl. 45, 
f. 1 (var. arenicola). 
V. Argenteae. Perennials, with leafy stems and more or less leafy many-flowered 
cymes. Flowers small. Petals slightly exceeding the sepals, yellow, obovate, and slightly 
emarginate. Stamens 20, with rather short filaments. Pistils numerous; styles short, 
rather stout, but neither thickened nor glandular at the base. 
re 21. Potentilla collina Wibel, Prim. Fl. Werth. 2: 267. 1799. 
i  PerSanial: stems many from the short rootstock, spreading or ascending, weak, gla- 
brous or tomentose; stipules small, less than 5 mm. long, lanceolate, acuminate; basal 
leaves many, on long strigose petioles 1-1.5 dm. long, digitate with 5 leaflets, smooth or 
puberulent above, grayish-tomentose beneath; leaflets broadly cuneate, 15-25 mm. long, 
deeply toothed above the middle with oblong-ovate obtuse teeth, and with flat, not revo- 
lute, margins; upper stem-leaves ternate, with oblong few-toothed leaflets; hypanthium 
grayish-tomentose, in fruit 5-7 mm. broad; bractlets and sepals subequal, oblong, obtuse 
or acute, nearly 4 mm. long; petals obcordate, cuneate, emarginate, a little exceeding the 
calyx; stamens 20; pistils many; styles filiform, short. 
TYPE LOCALITY: Wertheim, Germany. 
DISTRIBUTION : Western and central Europe ; sparingly introduced in Minnesota and Massa- 
chusetts. 
ILLUSTRATIONS : Lehm. Monog. Potent. £/. 10; Dietr. Fl. Bor. 12: /. 798 ; Sturm, Deuts. FI. 
91: £1. 9; Bot. Cab. 8: pl. 706. 
i 
22. Potentilla argentea L. Sp. Pl. 497. 1753. 
Fragaria argentea Crantz, Inst. 2: 177. 1766. 
Potentilla argentea dentata, DC. Prodr. 2: 577. 1825. 
Potentilla argyrops Raf. Aut. Bot. 165, 1840. 
Hypargyrium argenieum Fourr. Ann. Soc. Linn. Lyon II. 16: 371. 1868. 
Perennial ; stems many from the rootstock, rather bushy, branched and leafy, 1-5 dm. 
high, ascending, grayish-tomentose, or glabyate in age, often tinged with brown or purple; 
stipules from ovate-lanceolate and rarely 2-3-toothed to nearly linear and entire; leaves 
digitate, all except the uppermost with 5 leaflets, glabrous and green above, white-tomen- 
