161 Leaf made up of an even number of leaflets 162 



161 Leaf made up of an odd number of leaflets I"'* 



162 Tree unarmed; leaflets 10-22 in number, 8-15 cm. long 



FALSE CEDAR (CEDRELA) 



162 Tree spiny or prickly 1°^ 



163 More than one partly concealed bud in a leaf-axil; usually a 



spine above the axil and spines on older branches and the 



trunk HONEY-LOCUST (GLEDITSIA) 



163 Only one bud in an axil; no spines on trunk, spines at each side 



of leaf-scar, representing stipules....PEA-TREE (CARAGANA) 



164 Twigs prickly or spiny 



165 



164 Tree unarmed 1^6 



165 Leaflets showing almost transparent dots in blades 



PRICKLY ASH (ZANTHOXYLUM) 

 165 Leaflets without such dots LOCUST (ROBINIA) 



166 All leaflets alternate on rachis 



YELLOW-WOOD (CLADRASTIS) 



166 Most leaflets exactly or almost opposite on rachis 167 



167 Leaf-margin entire except for 2-4 coarse teeth near base ; leaf- 



lets 13-35 in number, 7-15 cm. long 



TREE OF HEAVEN (AILANTHUS) 



167 Leaf-margin entire or wavy ^"^ 



167 Leaf-margin toothed and sometimes lobed 172 



168 Twigs, petioles and rachis reddish-brown with sticky hairs 



CLAMMY LOCUST (ROBINIA) 

 168 Twigs, petioles and rachis not as just described 169 



169 Some leaflets more than 8 cm. long or else juice of young leaves 



milky - ^^^ 



169 No leaflets more than 8 cm. long 171 



170 Rachis winged or leaves crowded at tip of twig; winter-buds 

 solitary; 7-21 leaflets, juice of young leaves milky; some 

 species POISONOUS SUMAC (RHUS) 



170 Rachis never winged ; leaves sometimes crowded at tip of twig, 

 but buds superposed ; 5-9 leaflets, juice watery 



ENGLISH WALNUT (JUGLANS) 



25 



