10 KEY, BASED UPON LEAVES. 



g s . Lanceolate-oblong, 1-3 in. long, about equally acuminate at both 



ends 111. FORESTINA ACUMINATA. 



/ 4 . Equilateral and truncate at base, 



g. Serrate-dentate with cartilaginous teeth 



Deltoid-ovate 48. POPULUS MONILIFERA. 



Broadly deltoid 73. POPULUS DILATATA. 



g' 1 . Irregularly serrate or obscurely lobed 70. BETULA POPULIFOLIA. 



e 3 . Pinnately lobed; lobes 

 /. Rounded at apex (not bristle-pointed) and 



g. Subequal 38. QUERCUS ALBA. 



f/ 2 . Very unequal. 

 h. The two lobes next the summit much the largest. 



92. QUERCUS OBTUSILOBA. 

 h*. Lyrate-pinnatifid and sinuses extending 



Nearly to the midrib and roundish . . 39. QUERCUS MACROCARPA. 

 Usually not over half-way to the inidrid and more acute. 



66. Q. BICOLOR. 

 / 2 . Bristle-pointed; sinuses 



g. Moderately deep and narrow, lobes broad 15. QUERCUS RUBRA. 



g' 2 . Deeper and broader; lobes narrower 93. Q. TINCTORIA. 



g 3 . Deep, broad and rounded; lobes very narrow; acorn 

 Ovoid-oblong, immersed in a coarse-scaled cup. 



69. QUERCUS COCCINEA. 

 Flatened-globular, 4 immersed in a fine-scaled cup. 



94. QUERCUS PALUSTRIS. 

 e 4 . Broad, truncate at both base and apex, and with two spreading lobes on 



each side 2. LIRIODENDRON TULIPIPERA. 



e 5 . Wavy and spinous-toothed, very thick 52. ILEX OPACA. 



e 6 . Undulately crenate-toothed ; obovate-oblong, 



Slightly if at all pubescent beneath 67. QUERCUS PRINUS. 



Velvety pubescent beneath 116. QUERCUS MICHAUXII. 



e 7 . Sinuate-toothed, white-tomentose beneath. 96. POPULUS ALBA. 



e 9 . Cut-serrate or sublobate with slender petioles; 



Ovate, coarsely cut-serrate 83. PYRUS CORONARIA. 



Round-ovate, finely cut-serrate 86. CRAT^EGUS COCCLNEA. 



C 9 . Crenate-serrate; petioles 1 in. or slightly less in length. 



82. PRUNDS CERASUS. 

 e 10 . Obscurely crenulate-toothed; leaves 



Alternate, petioles long, mostly 1^ in. or more. 



87. CORNUS ALTERNIFOLIA. 



Opposite, petioles short (less than 1 in.) 88. CORNUS FLORIDA. 



e n . Doubly crenate -serrate with glandular teeth. 81. PRUNUS NIGRA. 



e 12 . Doubly serrate, rhombic-ovate 95. BETULA NIGRA. 



C? 2 . Main ribs several-palmately-veined, etc. 

 e. Rib single at first but soon sending off a strong vein on each side and 



leaves 3-lobed, 2-lobed or entire 32. SASSAFRAS OFFICINALE. 



e 9 . Ribs three at first, but soon five by branching, leaves alternate, base of 

 petiole concave and fitting over the axillary bud. 



13. PLATANUS OCCIDENTALS. 

 C 8 . Ribs 5-7 from commencement; leaves 

 /. Opposite base of petiole subtending (not Governing) the axillary bud. 



