TREES OP THE NORTHERN UNITED STATES 



CO. Leaflets broader and serrate ; usually large trees. 23. JEsculus. 

 DD. Leaves with radiating ribs. (FF.) 

 DD. Leaves with feather-veining. (EE.) 



EE. Leaves 2-6 in. long; flowers small, in large, dense, ter- 

 minal clusters 62. Syringa. 



EE. Leaves 1-4 in. long; flowers in pairs 48. Lonicera. 



FF. Leaves large, 6 in. or more long; two almost hidden buds, 

 one above the other, in the axils of the leaves on the rapid- 

 gro-wing branches; flowers large, purple, blooming in early 



spring ; fruit rounded pods .64. Paulownia. 



FF. Leaves large, 6 in. or more long; flowers large, white, bloom- 

 ing in June ; fruit long pods 65. Catalpa. 



FF. Leaves 2-4 in. long, with red stems 3. Cerddiphyllum. 



GG. Leaves scattered singly over the stem, not in bundles or 



clusters. (JJ.) 



GG. Leaves in large or small clusters. (HH. ) 

 HH. Clusters in whorls of many leaves around the stem like an 



umbrella 100. Sciadopitys. 



HH. Leaves clustered in bundles of 2-6 93. Pinus. 



HH. Leaves clustered in bundles of over 8. (II.) 



II. Leaves deciduous, soft 97. Larix. 



II. Leaves evergreen, rigid 98. Cedrus. 



JJ. Leaves hardly evergreen; spray quite slender. (ZZ.) 

 JJ. Leaves fully evergreen. (KK.) 

 KK. Leaves awl or scale shaped, and mainly appressed to the 



stem. (WW.) 



KK. Leaves linear or needle shaped, and decidedly spreading 

 from the stem, though sometimes with a decurrent base. 

 (LL.) 



LL. Leaves narrowed to a distinct though short stem. (RR.) 

 LL. Leaves sessile ; if narrowed, not so abruptly as to form a 



petiole. (MM.) 



MM. Leaves opposite or whorled on the stem. (PP.) 

 MM. Leaves rather spirally arranged around the stem, not just 



opposite. (NN.) 

 NX. Leaves linear to lanceolate, flattened, spreading quite 



squarely from the stem. (OO.) 



NN. Leaves not flattened but 4-sided, curved, gradually enlarging 

 from the tips to the bases, which are decurrent, and on the 

 young twigs completely cover the stem ; cones rounded ; the 



scales not lapping 105. Cryptomeria. 



OO. Leaves aboxit linear in form, of nearly the same width 

 throughout, and usually fastened to the cylindrical stem by a 

 distinct disk-like base; cones erect ; scales lapping. 96. Abies. 



