_a_ Leaves equally pinnate. Stipules wanting. Leaflets 2—4, generally oblong-obovate. Exothea (p. 714). Leaflets 6—12. Leaflets obtuse, usually oblong-obovate. Leaflets 8—12, 2′—3′ long, pale below; leaves occasionally opposite. Simarouba (p. 642). Leaflets 6—8, 1′—1½′ long, green below. Xanthoxylum coriaceum (p. 637). Leaflets 6—8, acuminate. Swietenia (p. 648). Stipules present. Branches armed with infra-stipular spines in pairs; leaflets 10—15, usually oblong-obovate, ½′—¾′ long, persistent. Olneya (p. 626). Branches unarmed; leaflets 20—46, ovals ½′—⅔′ long. Eysenhardtia (p. 620). _aa_ Leaves unequally pinnate. _b_ Stipules present. Leaflets sharply serrate; leaves deciduous; winter-buds resinous. Sorbus (p. 390). Leaflets entire or crenately serrate. Leaves deciduous. Leaflets 7—11, 3′—4½′ long; branches unarmed. Leaflets usually alternate, thin and glabrous at maturity. Cladrastis (p. 618). Leaflets opposite, coriaceous, pubescent beneath at least along the veins. Ichthyomethia (p. 628). Leaflets 9—21, 1—2 cm. long. Branches usually with stipular prickles, sometimes viscid. Robinia (p. 622). Branches unarmed, not viscid; leaflets 13—19, elliptic. Sophora affinis (p. 617). Leaves persistent. Leaflets 7—9, oblong-elliptic, 1′—2½′ long; branches unarmed. Sophora secundiflora (p. 616). Leaflets 10—15; branches prickly. Olneya (p. 626). _bb_ Stipules wanting. _d_ Leaves persistent. Leaflets long-stalked (_sometimes nearly sessile in Xanthoxylum flavum_). Leaflets oblong-ovate, cuneate at base. Leaflets acuminate, glabrous. Picramnia (p. 643). Leaflets obtuse, tomentose when unfolding. Xanthoxylum flavum (p. 636). Leaflets broad-ovate, usually rounded or subcordate at base. Metopium (p. 658). Leaflets sessile or nearly so. Petiole and rachis winged.