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..
Perennial erect branching herbs, with sheathing basal scales, alternate 3-foliolate or sometimes simple perfoliate leaves and showy yellow white or blue flowers in terminal or lateral racemes. Stipules foliaceous, or small, or none. Calyx campanulate, obtuse at base, or sometimes slightly turbinate, the teeth equal and separate, or the two upper ones united. Corolla and stamens as in Thermopsis. Ovary stipitate. Pod stalked, ovoid, oblong or nearly globose, pointed, inflated, the valves often coriaceous. [Greek, dyeing.]
About 24 species, natives of eastern and southern North America. Type species: Sophora alba L.
Flowers blue; plant glabrous.
Racemes numerous, terminal; plant glabrous.
Racemes few, lateral; plant more or less pubescent.
Flowers white or cream color.
Glabrous or nearly so.
Leaflets oblong or lanceolate, green in drying.
Leaflets obovate-cuneate, black in drying.
Glabrous, stout, 4°-6° high. Leaves short-petioled, 3-foliolate; leaflets oblanceolate or sometimes oval, obtuse at the apex, cuneate at the base, entire, 1'-2 1/2' long, sessile or nearly so; stipules lanceolate, equalling the petioles, or longer, persistent; racemes terminal, erect, loosely flowered, elongated (sometimes 10' long); bracts narrow, caducous; pedicels 2"-3" long; flowers indigo-blue, 9"-12" long; pod oblong, stout-stalked in the calyx, 1'-1 1/2' long, 5"-6" thick, tipped with the subulate style.
In rich soil, District of Columbia to western Pennsylvania, Missouri, Kansas, Georgia and Texas. Naturalized in the Connecticut River Valley, in Vermont, escaped from cultivation. June-Aug. Rattle-bush.
A hybrid of this species with B. bracteata has been observed by Prof. A. S. Hitchcock in Kansas.
Sophora tinctoria L. bp. Pl. 373. 1753. B. tinctoria R. Br. in Ait. Hort. Kew. Ed. 2, 3: 6. 1811.
Glabrous, erect, succulent, much branched, 2°-4° high. Leaves petioled, 3-foliolate; leaflets obovate or oblanceolate, 1/2'-1 1/2' long, sessile or nearly so, obtuse, cuneate at the base, entire, turning black in drying; stipules minute, caducous; racemes numerous, few-flowered, terminal; bracts minute, deciduous; pedicels 1"-2" long; flowers bright yellow, about 1/2' long; pods ovoid or nearly globose, 3"-5" long, tipped with the subulate style.