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..
Heuchera americana L. Sp. Pl. 226. 1753.
Stem rather stout, 2°-3° high, leafless, more or less glandular-hirsute. Basal leaves Iong-petioled, 3'-4' wide, with 7-9 rounded crenate-dentate lobes, the older ones glabrous, or with scattered hairs on the upper surface; flowering calyx broadly campanulate, nearly regular, 1 1/2"-3" long; petals very small, greenish, usually not exceeding the calyx-lobes; stamens much exserted; anthers orange.
Heuchera lancipÚtala Rydb., from Kentucky, has a leafless flower-stem as in H. americana; but the petals are much longer than the calyx-lobes.
H. roseola Rydb.; Britton, Man. 481. 1901.
Stem rather stout, 1°-3° high, leafy, glabrous below, puberulent above. Basal leaves ovate to suborbicular, 1 1/4'-9' wide, with rounded lobes and broad mucronate teeth, glabrous or sparingly pubescent and ciliate; flowering-calyx nearly regular, larger than in H. ameri-catia; petals purple or pink, usually much exceeding the calyx-lobes; stamens exserted.
In woods and on river bluffs. New York to Tennessee and South Carolina. May-July.
H. hispida hirsuticaulis Wheelock, Bull. Torr.
Club 17: 199. 1890. Heuchera hirsuticaulis Rydb.; Britton, Man.
Stem 1°-2 1/2° tall, villous-hirsute, leafless. Leaves 1 1/2' - 3 1/2' wide, on slender petioles which are pubescent like the stem, reniform to orbicular-ovate, with 7-11 rounded crenate-mucronate lobes; panicle lax, rather wide; flowering calyx campanulate, oblique, 2"-2 1/2" long, its lobes unequal; petals broadly spatulate, equalling the calyx-lobes or shorter; stamens long-exserted.
In dry woods and on bluffs, Michigan to Missouri, Indiana and Arkansas. May-June.
Heuchera Richardsonii R. Br. Frankl. Journ. 766. pl. 29. 1823.
Stem 2°-4° tall, hirsutely-pubescent or rarely nearly glabrous, usually leafless. Leaves 2'-3' wide, on long and slender petioles, broadly ovate-orbicular, with 5-9 shallow rounded dentate lobes; panicle strict, narrow; flowering calyx campanulate, very oblique, 3"-5" long, its lobes unequal; petals spatulate, slightly exceeding the calyx-lobes; stamens exserted.
In woods. Virginia to western Ontario, west to Kansas, Manitoba and Saskatchewan, south in the Rocky Mountains to Idaho. May-June.