[*] Achenes densely long-woolly, compressed; involucre far below the flower.
[+] Stem single, from a small tuber; sepals 10–20; style filiform.
2. A. Caroliniàna, Walt. Stem 3–6´ high; root-leaves once or twice 3-parted or cleft; involucre 3-parted, its wedge-shaped divisions 3-cleft; sepals 10–20, oblong-linear, purple or whitish; head of fruit oblong.—Ill. to Neb. and southward. May.
[+][+] Stems several; sepals 5–8; style filiform.
3. A. parviflòra, Michx. Stem 3–12´ high from a slender rootstock, 1-flowered; root-leaves 3-parted, their broadly wedge-shaped divisions crenate-incised or lobed; involucre 2–3-leaved; sepals 5 or 6, oval, white; head of fruit globular.—Lake Superior, northward and westward. May, June.
4. A. multífida, DC. Stems from a branching caudex, silky-hairy (6–12´ high); principal involucre 2–3-leaved, bearing one naked and one or two 2-leaved peduncles; leaves of the involucre short-petioled, similar to the root-leaves, twice or thrice 3-parted and cleft, their divisions linear; sepals obtuse, red, sometimes greenish-yellow or whitish; head of fruit spherical or oval.—Rocks, etc., N. E. Maine to Lake Superior, north and westward; rare. June.
[+][+][+] Taller, commonly branching above or producing two or more peduncles; involucral leaves long-petioled; sepals 5–8, silky or downy beneath (4–6´´ long), oval or oblong; style subulate.
5. A. cylíndrica, Gray. (Long-fruited A.) Slender (2° high), silky-pubescent; flowers 2–6, on very long upright naked peduncles; involucral leaves twice or thrice as many as the peduncles, 3-divided; their divisions wedge-lanceolate, the lateral 2-parted, the middle 3-cleft; lobes cut and toothed at the apex; sepals 5, rather obtuse, greenish-white; head of fruit cylindrical (1´ long).—Dry woods, N. Eng. to Mo., and northwestward. May.—Peduncles 7–12´ long, all from the same involucre and naked throughout, or one involucellate in the middle.
6. A. Virginiàna, L. More loosely pubescent or glabrate; involucral leaves 3, 3-parted; their divisions ovate-lanceolate, pointed, cut-serrate, the lateral 2-parted, the middle 3-cleft; peduncles elongated, the earliest naked, the others with a 2-leaved involucel at the middle, repeatedly proliferous; sepals 5, acute, greenish (in one variety white and obtuse); head of fruit oval or oblong.—Woods and meadows; common. June–August.—Plant 2–3° high; the upright peduncles 6–12´ long.
[*][*] Achenes naked, orbicular, compressed, wing-margined; sepals 5, obovate; involucre sessile.