This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", 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..
Iris versicolor L. Sp. PI. 39. 1753. Iris virginica L. Sp. PI. 39. 1753
Rootstock horizontal, thick, fleshy, covered with the fibrous roots. Stems terete or nearly so, straight or flexuous, 2°-30 tall, often branched above, leafy; leaves erect, shorter than the stem, somewhat glaucous, 6"-12" wide; bracts commonly longer than the pedicels, the lower one sometimes foliaceous; flowers several, violet-blue, variegated with yellow, green and white; perianth-segments glabrous, crestless, the outer ones spatulate, 2'-3' long, longer and wider than the inner; perianth-tube dilated upward, shorter than the ovary; capsule oblong, obscurely 3-lobed, about lĄ long and 8" in diameter; seeds 2"-3" broad, in 2 rows in each cell, the raphe indistinct.
Iris hexagona Walt. Fl. Car. 66. 1788.
Rootstock stout, thick. Stems terete, usually simple, straight or flexuous, leafy, 1°-3° tall; leaves 1/2-1 1/2' wide, green, not glaucous, the lower often 2°-3° long; flowers solitary in the upper axils, sessile, similar to those of I. versicolor, but larger, the broader outer crestless perianth segments often 4' long and over 1' wide, much wider than the erect inner ones; perianth-tube rather longer than the ovary, a little dilated upward; capsule oblong-cylindric, 6-angled, about 2' long; seeds in 2 rows in each cavity.
Rootstock stout, fleshy. Stem rather stout, simple or branched 2°-3° tall, equalled or exceeded by the bright green leaves which are 8"-1 1/4' wide; flowers solitary or 2 or 3 together, lilac, variegated with yellow, purple and brown, pedicelled; pedicels somewhat shorter than the bracts; outer perianth-segments broadly spatulate, 2}'-3' long, with narrow claws, the inner narrower and nearly erect; perianth-tube about 1/2' long above the ovary; capsule oblong, obtusely 3-angled, 1 1/2'-2' long; seeds in I row in each cavity, 4"-5" broad.
In swamps, southern Virginia and eastern North Carolina to Georgia and Louisiana. May-June.
Rootstock stout. Stem terete, zigzag, 1°- 1 1/2° tall; leaves conspicuously overtopping the inflorescence, green, 3/4'-1 1/4' wide, the larger ones about 2° long; flowers axillary, on pedicels 10"-14" long; perianth-segments bluish, spreading, 2 1/4 long, about 1' wide, not crested; capsule strongly 6-angled, oblong-cylindric, about 1 1/2 long, short-beaked; seeds in 2 rows in each cavity.
In swamps, Kentucky to Illinois, Missouri and Kansas. June-July.