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.
20. Wistaria. Pod tumid, marginless. Woody twiners; leaflets obscurely stipellate.
c. Standard narrow, erect; pod turgid or inflated; perennial herbs.
21. Astragalus. Keel not tipped with a point or sharp appendage. Pod with one or both the sutures turned in, sometimes dividing the cell lengthwise into two.
22. Oxytropis. Keel tipped with an erect point; otherwise as Astragalus.
23. Glycyrrhiza. Flowers, etc., of Astragalus. Anther-cells confluent. Pod prickly or muricate, short, nearly indehiscent.
[+][+][+] Herbs with pinnate or pinnately 1–3-foliolate leaves; no tendrils; pod transversely 2–several-jointed, the reticulated 1-seeded joints indehiscent, or sometimes reduced to one such joint. (Hedysareæ.)
[=] Leaves pinnate, with several leaflets, not stipellate.
24. Æschynomene. Stamens equally diadelphous (5 and 5). Calyx 2-lipped. Pod several-jointed; joints square.
25. Coronilla. Stamens unequally diadelphous (9 and 1). Calyx 5-toothed. Joints oblong, 4-angled. Flowers umbellate.
26. Hedysarum. Stamens unequally diadelphous (9 and 1). Calyx 5-cleft. Pod several-jointed; joints roundish.
[=][=] Leaves pinnately 3-foliolate, rarely 1-foliolate.
27. Desmodium. Stamens diadelphous (9 and 1) or monadelphous below. Calyx 2-lipped. Pod several-jointed. Flowers all of one sort and complete. Leaflets stipellate.
28. Lespedeza. Stamens diadelphous (9 and 1); anthers uniform. Pod 1–2-jointed. Flowers often of 2 sorts, the more fertile ones apetalous. Leaflets not stipellate.
29. Stylosanthes. Stamens monadelphous; anthers of 2 sorts. Pod 1–2-jointed. Calyx deciduous, the tube narrow and stalk-like. Leaflets not stipellate.
[+][+][+][+] Herbs with abruptly pinnate leaves, terminated by a tendril or bristle; stamens diadelphous; pod continuous, 2-valved, few–several-seeded. (Vicieæ.)
30. Vicia. Wings adherent to the keel. Style filiform, bearded with a tuft or ring of hairs at the apex.
31. Lathyrus. Wings nearly free. Style somewhat dilated and flattened upwards, bearded down the inner face.
[+][+][+][+][+] Twining (sometimes only trailing) herbs, leaves pinnately 3- (rarely 1- or 5–7-) foliolate; no tendrils; peduncles or flowers axillary, pod not jointed, 2-valved. (Phaseoleæ.)
[=] Leaves pinnate.
32. Apios. Herbaceous twiner; leaflets 5–7. Keel slender and much incurved or coiled.
[=][=] Leaves 3-foliolate. Ovules and seeds several. Flowers not yellow.
33. Phaseolus. Keel spirally coiled; standard recurved-spreading. Style bearded lengthwise. Flowers racemose. Seeds round-reniform.
34. Strophostyles. Keel long, strongly incurved. Style bearded lengthwise. Flowers sessile, capitate, few. Seeds oblong, mostly pubescent.
35. Centrosema. Calyx short, 5-cleft. Standard with a spur at the base; keel broad, merely incurved. Style minutely bearded next the stigma.
36. Clitoria. Calyx tubular, 5-lobed. Standard erect, spurless; keel scythe-shaped. Style bearded down the inner face.
37. Amphicarpæa. Calyx tubular, 4–5-toothed. Standard erect; keel almost straight. Style beardless. Some nearly apetalous fertile flowers next the ground.
38. Galactia. Calyx 4 cleft, the upper lobe broadest and entire. Style beardless. Bract and bractlets minute, mostly deciduous.
[=][=][=] Leaves 1–3-foliolate. Ovules and seeds only one or two. Flowers yellow.
39. Rhynchosia. Keel scythe shaped. Calyx 4–5-parted. Pod short.
Suborder II. Cæsalpinieæ. (Brasiletto Family.) Corolla perfectly or not at all papilionaceous, sometimes nearly regular, imbricated in the bud, the upper or odd petal inside and enclosed by the others, Stamens 10 or fewer, commonly distinct, inserted on the calyx. Seeds anatropous, often with albumen. Embryo straight.
[*] Flowers imperfectly papilionaceous, perfect. Trees.
40. Cercis. Calyx campanulate, 5-toothed. Pod flat, wing-margined. Leaves simple.
[*][*] Flowers not at all papilionaceous, perfect. Calyx 5-parted. Herbs.
41. Cassia. Leaves simply and abruptly pinnate, not glandular-punctate.
42. Hoffmanseggia. Leaves bipinnate, glandular-punctate.
[*][*][*] Flowers not at all papilionaceous, polygamous or diœcious. Trees.
43. Gymnocladus. Leaves all doubly pinnate. Calyx-tube elongated, at its summit bearing 5 petals resembling the calyx lobes. Stamens 10.
44. Gleditschia. Thorny; leaves simply and doubly pinnate. Calyx tube short; its lobes, petals, and the stamens 3–5.
Suborder III. Mimoseæ. (Mimosa Family.) Flower regular, small. Corolla valvate in æstivation, often united into a 4–5-lobed cup, hypogynous, as are the (often very numerous) exserted stamens. Embryo straight. Leaves twice pinnate.
45. Desmanthus. Petals distinct. Stamens 5 or 10. Pod smooth.
46. Schrankia. Petals united below into a cup. Stamens 8 or 10. Pod covered with small prickles or rough projections.
1. BAPTÍSIA, Vent. False Indigo.
Calyx 4–5-toothed. Standard not longer than the wings, its sides reflexed; keel-petals nearly separate, and, like the wings, straight. Stamens 10, distinct. Pod stalked in the persistent calyx, roundish or oblong, inflated, pointed, many seeded.—Perennial herbs, with palmately 3-foliolate (rarely simple) leaves, which generally blacken in drying, and racemed flowers. (Named from βαπτίζω, to dye, from the economical use of some species, which yield a poor indigo.)
[*] Racemes many, short and loose, terminal, often leafy at base, flowers yellow.
1. B. tinctòria, R. Br. (Wild Indigo.) Smooth and slender (2–3° high), rather glaucous; leaves almost sessile, leaflets rounded wedge-obovate (½–1½´ long), stipules and bracts minute and deciduous, pods oval-globose, on a stalk longer than the calyx.—Sandy dry soil, N. Eng. to Fla., west to Minn. and La.
[*][*] Racemes fewer, opposite the leaves.
[+] Flowers yellow.
2. B. villòsa, Ell. Sometimes soft-hairy, usually minutely pubescent when young, erect (2–3° high) with divergent branches; leaves almost sessile, leaflets wedge-lanceolate or obovate, lower stipules lanceolate and persistent, on the branchlets often small and subulate, racemes many-flowered; pedicels short; bracts subulate, mostly deciduous; pods ovoid-oblong and taper-pointed, minutely pubescent.—Va. to N. C. and Ark.
[+][+] Flowers white or cream-color.
3. B. leucophæ̀a, Nutt. Hairy, low (1° high), with divergent branches; leaves