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, or sometimes shrubs, with usually glandular-punctate foliage, odd-pinnate leaves, minute stipules, and small purple white or yellow flowers in terminal or lateral spikes. Calyx-teeth nearly equal; standard cordate or auriculate, clawed; wings and keel mainly exceeding the standard; adnate by their claws to the lower part of the stamen-tube. Stamens 10 or 9, monadelphous; anthers uniform. Ovary sessile or short-stalked; ovules 2 or 3; style subulate. Pod included in the calyx, membranous, mostly indehiscent and 1-seeded. [Anagram of Psoralea.]
Perhaps 150 species, natives of western North America, Mexico and the Andean region of South America. In addition to the following some 50 others occur in the western United States. Type species: Dalea obovatifolia Ort.
Spikes elongated, narrow, loosely flowered.
Foliage glabrous; corolla white; leaflets linear.
Foliage pubescent; corolla purple; leaflets obovate.
Spikes oblong, thick, densely flowered.
Foliage glabrous; corolla pink or white; leaflets 15-41.
Foliage pubescent; corolla yellow to red; leaflets 3-9.
Plant 1° - 2o high: calyx-teeth acuminate.
Plants not over 10" high; calyx-teeth aristate.
Dalea enneandra Nutt. Fraser's Cat. 1813.
Erect, glabrous, 1°-4° high, with numerous slender ascending branches. Leaflets 5 - 11, linear or linear-oblong, obtusish, 2 -5" long, 1/2"-1" wide, narrowed at the base, nearly sessile; spikes numerous, 2'-5' long, loosely flowered; bracts obtuse, nearly orbicular, punctate, membranous-margined, \\" long, often mucronate; flowers 4"-6" long; calyx-teeth subulate, beautifully plumose, shorter than the white corolla; standard small, cordate; keel exceeding the wings; stamens 9.
Prairies, Iowa to South Dakota and Colorado, south to Mississippi and Texas. June-Aug.