[+][+] Herbaceous perennials, more or less white-tomentose; leaflets incisely pinnatifid; bractlets and sepals nearly equal; stamens 20–25.
5. P. Pennsylvánica, L. Stems erect or decumbent at base (½–2° high); leaflets 5–9, white-tomentose beneath, short-pubescent and greener above, oblong, obtuse, the linear segments slightly or not at all revolute; cyme fastigiate but rather open.—Coast of Maine, N. H., and the lower St. Lawrence, L. Superior, and westward. July, Aug.—Var. strigòsa, Lehm. Stems 6–12´ high; silky-tomentose throughout; leaflets deeply pinnatifid, the margins of the narrow lobes revolute; cyme short and close.—Minn. and westward.
§ 2. Styles filiform, not glandular at base; inflorescence cymose.
[*] Style terminal; achenes glabrous; stamens 20; herbaceous perennials, with rather large yellow flowers.
[+] Leaves pinnate.
6. P. Hippiàna, Lehm. Densely white-tomentose and silky throughout, the upper surface of the leaves a little darker; stems ascending (1–1½° high), slender, branching above into a diffuse cyme; leaflets 5–11, cuneate-oblong, incisely toothed at least toward the apex, diminishing uniformly down the petiole; carpels 10–30.—N. W. Minn., and westward.
7. P. effùsa, Dougl. Tomentose throughout, with scattered villous hairs; stems ascending (4–12´ high), diffusely branched above; leaflets 5–11, interruptedly pinnate, the alternate ones smaller, cuneate-oblong, coarsely-incised-serrate or dentate; carpels 10.—W. Minn. to Mont. and Col.
[+][+] Leaves palmate, of 3 or 5 leaflets; tomentose or villous.
8. P. argéntea, L. (Silvery Cinque-foil.) Stems ascending, paniculately branched at the summit, many-flowered, white-woolly; leaflets 5, wedge-oblong, almost pinnatifid, entire toward the base, with revolute margins, green above, white with silvery wool beneath.—Dry barren fields, etc., N. Scotia to N. J., west to Dak. and E. Kan. June–Sept. (Eu.)
9. P. frígida, Vill. Dwarf (1–3' high), tufted, villous when young; leaflets 3, broadly cuneate-obovate, deeply 3–5-toothed at summit, nearly glabrous above; flowers mostly solitary, small, on very slender stems; bractlets and sepals equal.—Alpine summits of the White Mts. (Eu.)