Plants perennial herbs, often blackening upon drying, deeply rooted with thick, woody rhizomes and a woody crown. Stems erect or ascending to trailing or spreading, unarmed, mostly unbranched below the midpoint, glabrous or pubescent with short, fine hairs, sometimes glaucous. Leaves alternate, palmately trifoliate (the uppermost sometimes reduced to 1 or 2 leaflets, those toward the stem base usually reduced and scalelike), short- to long-petiolate, the lowermost and sometimes also the uppermost sessile or nearly so). Stipules variously poorly developed, inconspicuous, and shed early, or well-developed, similar to the leaflets, and persistent; stipels absent. Leaflets mostly oblanceolate to obovate, glabrous or hairy, sometimes glaucous, pinnately veined, the lateral veins sometimes inconspicuous. Inflorescences terminal or axillary racemes, stalked, the bracts herbaceous, small, lanceolate, and shed early, or larger, similar to the leaflets, and persistent; bractlets usually absent. Flowers short- to long-stalked. Calyces more or less 2-lipped, but usually appearing 4-lobed, the tube bell-shaped, slightly zygomorphic, the lobes usually shorter than the tube, the upper lobe broadly triangular to oblong-triangular, usually bluntly or broadly pointed at the tip, occasionally shallowly notched or shallowly 2-lobed, the other 3 lobes similar, triangular to broadly triangular, sharply pointed at the tips. Corollas papilionaceous, white, yellow, or purplish blue, the banner broadly obovate, to nearly circular or kidney-shaped, shorter than to about as long as the wings, somewhat curved upward, the sides curved or curled back, rounded or shallowly notched at the tip, the wings oblong, straight, the keel about as long as the wings, boat-shaped, fused toward their tips, usually rounded at the tip, straight or slightly curved upward. Stamens 10, all similar in length, the filaments not fused, the anthers attached near the base, mostly yellow. Ovary short-stalked, the style curved, glabrous, at least toward the tip, at least the basal portion persistent at fruiting, the stigma minute, terminal. Fruits legumes globose to oblong-ellipsoid or oblong-ovoid, sometimes asymmetrically so, strongly inflated, not flattened, straight, with 1 locule), dehiscent tardily, often from the tip, with few to more commonly numerous seeds. Seeds ellipsoid to irregularly kidney-shaped, usually shallowly notched at the attachment point, the surface more or less smooth, but with few to numerous pustular resinous dots. Fifteen to 17 species, temperate North America, most diverse in the eastern and central United States.

Baptisia is generally recognized by its trifoliate leaves that often blackening upon drying, racemes of large flowers, separate stamens, and greatly inflated fruits with a prominent beak. The species in Missouri are relatively easily distinguished. However, the taxonomy has been complicated by a series of nomenclatural changes at the level of both species and variety.

Baptisia has been the subject of important studies on interspecific hybridization. Larisey (1940) recognized eight hybrid taxa and noted that they are especially common in areas where the boundaries of widespread species overlap. In a groundbreaking chemosystematic study, Alston and Turner (1963) used flavonoid chromatography to study hybrids between four species of Baptisia in southeast Texas. They showed that the hybrids possessed a combination of chemical compounds found separately in the parental species.

Baptisia is closely related to the western genus Thermopsis R. Br., which differs mainly in having linear, uninflated fruits (B. L. Turner, 1981). The separate filaments in Baptisia are thought to be a primitive trait relating Baptisia with the relatively primitive woody genus Sophora, a relationship supported by some molecular evidence (Doyle et al., 1997). Chemically, Baptisia is similar to Lupinus and its relatives. Baptisia contains the quinolizidine lupine alkaloids cytisine and N-methylcytisine, as well as the pyridone alkaloid anagyrine in large quantities (Cranmer and Mabry, 1966). The use of Baptisia as a forage plant is limited by the presence of these bitter compounds. It is avoided by horses and cattle, although deer are said to eat the flowers.

Baptisia species are good indicators of former prairies, glades, and savannas. In wooded areas, they persist in openings and along edges for many years, but decrease as the canopy covers them. Several species are cultivated as ornamentals. Their deep taproots enable them to withstand drought and neglect. The generic name Baptisia originates from the Greek word bapto, meaning to dip or dye, in reference to the former use of these plants as a substitute for the blue dye plant indigo (Indigofera L.), hence the common name false or wild indigo.