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, slender, sparingly branched, 1°-2 1/2° high, more or less pubescent and rough. Glands of the foliage small and inconspicuous; leaves petioled, pinnately 3-foliolate; petioles shorter than or equalling the leaflets; stipules subulate; leaflets oblong-lanceolate, 1 1/2' - 3' long, 4"-7" wide, entire, obtuse at each end, the apex mucronulate, the terminal one on a stalk 2"-6" long; racemes axillary and terminal, on peduncles much exceeding the leaves, rather loosely flowered, 2-5' long; bracts ovate-lanceolate, acuminate, early deciduous, glandular; flowers purplish, about 2" long; pod nearly orbicular, strongly wrinkled transversely.
Stylosanthes racemosa Nutt. Fraser Cat. Name only. 1813.
Psoralea Onobrychis Nutt. Gen. 2: 104. 1818.
Glabrous or slightly pubescent, branched, 3°-6° high. Glands of the foliage few and small; stipules subulate; petioles about equalling the 3-foliolate leaves; leaflets ovate-lanceolate, 2-4' long, 1'-2' wide, entire, rounded or truncate at the base, acuminate at the apex, the terminal one on a stalk about 1' long; racemes numerous, axillary and terminal, very slender and loosely flowered, 3'-6' long; peduncles equalling or shorter than the leaves; flowers purplish, 1 1/2'-2' long; pod obliquely ovoid, 4"-6" long, transversely wrinkled and roughened with points.
17. AMÓRPHA L. Sp. Pl. 713. 1753.
Glandular-punctate shrubs, with odd-pinnate leaves, and small violet blue or white flowers, in dense terminal spicate racemes. Calyx-teeth nearly equal, or the lower ones longer; standard obovate, erect, clawed, folded around the stamens and style; wings and keel none. Stamens monadelphous below; anthers all alike. Ovary sessile, 2-celled; style curved; stigma terminal. Pod short, oblong, curved, nearly indehiscent, 1-2-seeded. [Greek, deformed, four petals being absent.]
About 15 species, natives of North America and Mexico. Type species: Amorpha fruticosa L.
Tall shrub; leaflets 1' - 2' long; pod usually 2-seeded.
Low shrubs; leaflets 3"-6" long; pod 1-seeded.
Glabrous or nearly so; spikes commonly solitary.
Densely canescent; spikes commonly clustered.