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..
Annual glabrous branching erect or diffuse herbs, with small yellow flowers and 3-foliolate leaves. Calyx of 4 sepals. Petals 4, sessile, not clawed. Receptacle short, glandless. Stamens 6, inserted on the receptacle. Ovary short, long-stalked. Capsule short, rhomboid or trapezoid, often broader than long, 4-10-seeded. [Diminutive of Cleome.]
A genus of about 8 species, natives of southwestern North America, extending into Mexico. Type species: Cleomella mexicana DC.
Generally erect, 1°-1 1/2° high, branching above. Leaflets linear-lanceolate or linear-oblong, longer than the petiole; bracts linear, simple; flowers yellow, 2"-3" broad; pedicels very slender, 1/2' long in fruit; pod flattened, rhomboid, 2"-3" broad, about 2" high, pointed, raised on a very slender stipe 2"-4" long, its valves almost conic; placentae persistent after the valves fall away, each bearing about 3 seeds.
Plains, Nebraska and Colorado to Texas and New Mexico. Summer.