13. Psoralea. Corolla truly papilionaceous. Stamens 10, half of the anthers often smaller or less perfect. Leaves mostly palmately 3–5-foliolate.
14. Amorpha. Corolla of one petal! Stamens 10, monadelphous at base.
15. Dalea. Corolla imperfectly papilionaceous. Stamens 9 or 10; the cleft tube of filaments bearing 4 of the petals about its middle.
16. Petalostemon. Corolla scarcely at all papilionaceous. Stamens 5; the cleft tube of filaments bearing 4 of the petals on its summit.
[=][=] Herbage not glandular-dotted (except in n. 23); stamens mostly diadelphous; pod 2-valved, several-seeded; leaves pinnately several-foliolate; flowers racemose.
a. Wings cohering with the keel; pod flat or 4-angled; hoary perennial herbs.
17. Tephrosia. Standard broad. Pod flat. Leaflets pinnately veined.
18. Indigofera. Calyx and standard small. Pod 4-angled. Leaflets obscurely veined.
b. Flowers large and showy; standard broad; wings free; woody; leaflets stipellate.
19. Robinia. Pod flat, thin, margined on one edge. Trees or shrubs.