350 NORTH AMERICAN FLORA [VoLuME 22 
veiny beneath, nearly glabrous above; leaflets obovate, divided to near the midrib into 
linear-oblong obtuse divisions; hypanthium strigose and slightly tomentose, in fruit about 
8mm. in diameter; bractlets lanceolate-oblong, about 4-5 mm. long ; sepals ovate-triangular, 
acuminate, 5-6 mm. long; petals obovate, cuneate, truncate or slightly emarginate, about 
equaling the calyx; stamens 20-25; styles short, terminal, thickened and glandular at the 
base; achenes smooth, numerous, : 
TYPE LOCALITY : Canada. . 
DISTRIBUTION : Sandy or rocky shores, Newfoundland and Labrador to New Hampshire and 
Quebec ; also on Hudson Bay. 
fl ILLUSTRATIONS: Britt. & Brown, Ill. Fl. f. 1970; Mem. Dep. Bot. Columbia Univ. 2: £1. 37, 
1S, 
171. Potentilla glabrella Rydb. Mem. Dep. Bot. Columbia 
Univ. 2: 94. 1898. 
Potentilla sericea glabrata Hook. F1. Bor, Am. 1: 189. 1832. Not P. glabrata Willd. 1813. 
Potentilla pennsylvanica glabrata §. Wats. Proc. Am. Acad. 8: 554. 1873. 
Perennial, with a short caudex; stem generally erect and strict, rather low, 1-2 dm. 
high, glabrate or sparingly pubescent; stipules ovate, pectinately toothed; leaves pinnate, 
with 5-11 rather approximate leaflets, glabrate or glandular-pruinose, sparingly hairy 
on the veins and margins ; leaflets obovate to oblanceolate, the lower ones smaller, very 
deeply dissected into oblong, acute or obtuse segments; cyme rather few-flowered; hypan- 
thium hirsute or puberulent; bractlets oblong or lanceolate, somewhat shorter than the 
broadly ovate sepals, both rather strongly veined, about 5 mm. long; petals obovate, about 
equaling the sepals; stamens 20; pistils very numerous; styles short, fusiform and glandular 
below. 
TYPE LOCALITY: Rocky Mountains [British America]. 
DISTRIBUTION : From Saskatchewan and Alberta to Wyoming. 
172. Potentilla pennsylvanica L. Mant. 76. 1767. 
Potentilla missourica Hornem.; Lindl. Bot. Reg. 17: pl. 1422. 1831. 
? Potentilla missourica Schrad. Ind. Sem. Hort. Goetting. 1832 ; ae 8: Litt. 26. 1833. 
Potentilla pennsylvania communis T. & G. Fl, N. Am. 1: 438. 1840. 
Potentilla pennsylvanica missourica Lehm. Stirp. Pug. 9: 41. 1851. 
Perennial; stem generally erect, strict, 4-8 dm. high, more or less appressed-pubescent 
and tomentulose; stipules ovate in outline, 1-2 cm. long, often pectinately divided; leaves 
pinnate with 7-15 leaflets, grayish-tomentose and veiny beneath, short-strigose and green 
above, the lower long-petioled, the upper subsessile; leaflets gradually reduced downward, 
often somewhat decurrent on the rachis, oblong or oblanceolate in outline, divided halfway to 
the midrib into oblong divisions, the margins scarcely at all revolute ; cyme dense, with erect 
branches ; flowers short-pedicelled ; hypanthium densely pubescent, tomentose and strigose ; 
bractlets lanceolate, acute, equaling the ovate-triangular acute sepals, usually not prom- 
inently veiny, about 5 mm. long; petals obovate, cuneate, slightly emarginate or truncate, 
about 6 mm. long; stamens about 20; pistils numerous; styles thickened and glandular 
below. 
TYPE LOCALITY : Canada. 
DISTRIBUTION : On the plains, from Hudson Bay to the Yukon Territory and Colorado. 
ILLUSTRATIONS : Jacq. Hort. Vind. 2: pl. 189 ; pe Reg. 17: pi. 1412; Britt. & Brown, Ill. 
Fl. f. 1929 ; Mem. Dep. Bot. Columbia Univ. 2: pL 3. 8, f. 1. 
Achim) Ry db. Cbmnte rr 
173. Potentilla arachnoidea(Douglas, sp. nov. 
Potentilla pennsylvanica conferta A. Gray, Mem. Am, Acad. II. 4: 42. 1849. Not P. conferia 
Bunge. 1830. 
Potentilla pennsylvanica arachnoidea Lehm. Stirp. Pug. 9: 41. 1851. 
Potentilia arachnoidea Dougl.; Lehm. Stirp. Pug. 9: 41, asasynonym. 1851. 
Perennial, with a short cespitose caudex, in habit closely resembling P. strigosa; stems 
densely pubescent, with partly short, partly longer appressed hairs, 1-3 dm. high, erect, 
strict; basal leaves pinnate, with 9-13 leaflets; petioles densely pubescent with short 
pubescence and longer ascending or appressed hairs; leaflets obovate or oblanceolate, 1-3 
cm. long, green and rather densely short-puberulent above, grayish-tomentose and silky on 
