10 KEY, BASED UPON LEAVES. 



h?. Without glands, 



Glabrous both sides, sharply serrate. 



59. AMELANCHIER CANADENSIS. 



Downy under-side and petiole .30. PYRUS MALUS. 



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. POPDLUS DILATATA. 



g*. 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. 



g' 2 . Very unequal. 

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



92. QUERCUS OBTUSILOBA. 



W. Lyrate-pinnatifid and sinuses extending 



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

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



66. Q. BICOLOR. 

 ll z . Irregularly lobed with broad lobes and narrow sinuses. 



136. Q. GARRYANA. 

 f*t Bristle-pointed; sinuses 



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



g*. Deeper and broader; lobes narrower 93. Q. TINCTORIA. 



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

 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 1 . Sinuate-toothed, white-tomentose beneath 96. POPULUS ALBA. 



e 8 . Cut-serrate or sublobate with slender petioles; 



Ovate, coarsely cut-serrate 83. PYRUS CORONARIA. 



Round-ovate, finely cut-serrate 86. CRAT.EGUS COCCINEA. 



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



82. PRUNUS CERASUS. 

 6 10 . Obscurely crenulate-toothed; leaves 



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



87. CORN us ALTERNIFOLIA. 



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



e 11 . Doubly crenate-serrate with glandular teeth 81. PRUNUS NIGRA. 



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



ei 2 . Main ribs several, palinately- veined, etc. 



