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..
Herbs, sometimes slightly woody, with simple (or in some tropical species 3-7-foliolate) leaves, and racemose flowers. Calyx 5-toothed, slightly 2-lipped. Standard orbicular or ovate, often cordate; wings oblong or obovate; keel curved. Stamens monadelphous, their sheath deeply cleft; anthers of 2 forms, alternating with each other, the one small, versatile, the other larger. Ovary sessile or short-stalked; style more or less curved. Pod oblong or globose, inflated, coriaceous or membranous, many-seeded, the seeds loose at maturity. [Greek, a rattle.]
About 250 species, mainly natives of tropical regions. Besides the following, some 7 others occur in the southern and southwestern United States. Type species: Crotalaria lotifolia L.
Stem and branches erect or ascending; leaves, at least the upper, lanceolate or oblong.
Stems prostrate, from a deep root; leaves broadly oblong or oval.
Crotalaria sagittalis L. Sp. Pl. 714. 1753.
Annual, erect or decumbent, villous-pubes-cent, branching, rarely over 1° high. Leaves simple, oval, lanceolate or oblong, acute or obtusish at the apex, rounded at the base, entire, nearly sessile, 1'-2 1/2' long, 2"-8" wide; stipules persistent and united, decurrent on the stem, sagittate above, or the lower wanting; peduncles 1'-4' long, 2-4-flowered; pedicels 1"-3" long; flowers yellow, 4"-6" long, the corolla about equalling the calyx; pod oblong, glabrous, nearly sessile in the calyx, 1' long, 4"-5" in thickness, much inflated, nearly black at maturity; seeds shining.
Am. 2: 55. 1803. Crotalaria rotundifolia Poir. in Lam. Encycl.
Perennial by a deep somewhat woody root, the slender branches usually prostrate. Pubescence mostly dense, brownish, spreading or ascending; leaves broadly oblong or oval, obtuse at both ends, or narrowed at the base, paler beneath than above, \'-\\' long; petioles 1"-2" long; upper stipules usually distinctly sagittate, the lower much smaller, or often wanting; peduncles lateral, 2'-6' long, slender, 2-6-flowered; flowers usually distant, yellow, 6"-8" long; corolla little longer than the calyx; pod nearly as in the preceding species.
Crotalaria Púrshii DC, of the southern United States, another perennial deep-rooted species, but with leaves linear to oblong, stems erect or ascending, and. merely puberulent, is recorded as entering our area in southern Virginia.