This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Erect perennial herbs. Basal leaves lobed, divided or dissected, those of the stem forming an involucre near to or remote from the peduncled flower or flowers. Sepals 4-20, petaloid. Petals none. Stamens 00, shorter than the sepals. Carpels 00. Achenes compressed, 1-seeded. [From the Greek, a flower shaken by the wind.]
About 85 species, widely distributed through the temperate and subarctic regions of both hemispheres. About 20 species are natives of North America. Type species: Anemone coronaria L.
* Achenes densely woolly.
Stem simple, slender, 1-flowered.
Root tuberous; sepals 6-20, narrow.
Rootstock slender; sepals 5-6, oval.
Stem commonly branching above, tall, generally 2-several-flowered.
Leaves of the involucre sessile or short-petioled; sepals red; head of fruit globose or oval.
Head of fruit cylindric; divisions of the leaves wedge-shaped, narrow.
Head of fruit oblong or oval; divisions of the leaves ovate, broad.
** Achenes pubescent, or nearly glabrous.
Leaves of the involucre sessile.
Stout, 1°-2° high, branching and bearing several flowers; carpels nearly orbicular; flowers white.
Slender, 2' - 12' high, 1-flowered; carpels narrow; flowers yellow.
Leaves of the involucre petioled.
Involucral leaf-divisions lobed and incised; plant 4'-9' high.
Involucral leaf-divisions dentate; plant 10'-16' high.
Anemone caroliniana Walt. Fl. Car. 157. 1788.
Sparsely hairy, 4'-10' high, arising from a tuber 3"~4" in diameter. Basal leaves slender-petioled, 3-divided, the divisions variously toothed, lobed and parted, those of the involucre sessile and 3-cleft; flower erect, 9"-18" broad; sepals 6-20, linear-oblong, purple, varying to white; head of fruit oblong; achenes densely woolly.
Open places, Illinois to Wisconsin and South Dakota, south to Florida and Texas. Mayflower. April-May.
Anemone decapétala Ard., of the southern United States, Mexico and South America, ranging north to Kansas, differs by some or all of its basal leaves having the divisions merely crenate.