XXVI ANALYTICAL KEY TO THE GENERA 



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, l'-25' long; branches unarmed. 



Sophora secundiflora (p. 616). 



1 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. 



Leaflets crenate, obovate, about ^' 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 f ' long. 



Pistacia (p. 656). 

 Petiole and rachis not winged. 



Leaflets 7-19, acuminate, 2'-5' long. Sapindus marginatus (p. 713). 

 Leaflets 21-41, obtuse, |'-f 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 



i' long. Bursera microphylla (p. 647). 



