Leaflets crenate, obovate, about ½′ long; branches prickly. Xanthoxylum Fagara (p. 634). Leaflets entire. Leaflets oblong, usually acute, 3′—4′ long. Sapindus saponaria (p. 712). Leaflets spathulate, rounded at apex, not more than ¾′ long. Pistacia (p. 656). Petiole and rachis not winged. Leaflets 7—19, acuminate, 2′—5′ long. Sapindus marginatus (p. 713). Leaflets 21—41, obtuse, ½′—¾′ long. Alvaradoa (p. 644). _dd_ Leaves deciduous. Leaflets long-stalked, 3—7, entire, acute. Bursera (p. 645). Leaflets sessile or nearly so. Branches prickly; leaflets crenate. Xanthoxylum clava-Herculis (p. 635). Branches unarmed. Juice milky or viscid; leaflets serrate or entire; rachis sometimes winged. Rhus species 1—3 (p. 660). Juice watery. Rachis without wings. Leaflets entire, acuminate, 7—9. Sapindus Drummondii (p. 714). Leaflets serrate or crenate. Winter-buds large; leaflets 5—23, aromatic. Winter-buds naked. Juglans (p. 169). Winter-buds covered with scales. Carya (p. 176). Winter-buds minute, globose, scaly; leaflets 5—7, ovate, not aromatic. Ungnadia (p. 717). Rachis winged; leaflets 10—20, entire, rounded at apex, not more than ¼′ long. Bursera microphylla (p. 647). TREES OF NORTH AMERICA (Exclusive of Mexico) Class 1. GYMNOSPERMÆ. Ovules and seeds borne on the face of a scale, not inclosed in an ovary; resinous trees, with stems increasing in diameter by the annual addition of a layer of wood inside the bark. I. PINACEÆ.