10 KEY, BASED UPON LEAVES. 



gr 2 . Very unequal. 

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



92. QUERCUS OBTUSILOBA. 



/i. 2 . Lyrate-pinnatifid and sinuses extending 

 Nearly to the midrib and roundish. 



89. QUERCUS MACROCARPA. 

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



66. Q. BICOLOR. 

 /*. Bristle-pointed ; sinuses 



g. Moderately deep and narrow; 



Lobes narrowing towards apex and mostly terminating in 1-3 



bristle-pointed teeth 15. Q. RUBRA. 



Lobes generally widening towards apex and terminating in 3-7 



bristle-pointed teeth 162. Q. CALIFORNICA. 



gr 2 . Deeper and broader ; lobes narrower 93. Q. TINCTORIA. 



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

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



69. QUERCUS COCCINEA. 

 Flattened-globular, 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 TULIPIFERA. 



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. CRATJEGUS COCCINEA. 



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



82. PRUNUS 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 11 . Undulate-serrate, |~f in. long and bearing large scattered glands. 



154. DALEA SPINOSA. 



e 12 . Doubly crenate-serrate with glandular teeth 81. PRUNUS NIGRA. 



e 13 . Doubly serrate, rhombic-ovate 95. BETULA NIGRA. 



d?. Main ribs several, paltnately-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 2 . Ribs three at first, but soon five by branching, leaves alternate, base 

 of petiole concave and fitting over the axillary bud, obscurely 



3-5 lobed with broad shallow sinuses 13. PLAT ANUS OCCIDENTALS. 



5-lobed with narrow and deeper sinuses. . . 135. PLATANUS RACEMOSA. 

 e 3 . Ribs 5-7 from commencement ; leaves 



f. Opposite, base of petiole subtending (not covering) the axillary bud. 

 g. Moderately incised with broad lobes which are 



Sparingly sinuate-toothed 7. ACER SACCHARINUM. 



Irregularly serrate and notched 53. ACER RUBRUM. 



Sharply and finely doubly serrate. .79. ACER PENNSYLVANICUM. 

 f/ 2 . Deeply incised with more or less acute sinuses and narrow lobes. 

 h. Star-shaped, lobes glandular serrate. 



60. LlQUIDAMBAR STYRACIFLUA. 



h*. Palmate 



Lobes incisely toothed 26. ACER DASYCARPUM. 



Lobes furnished with 2-4 lobes 152. A. MACROPHYLLUM. 



/ 2 . Alternate, tendril bearing vine 78. VITIS AESTIVALIS. 



c 2 . Linear, sessile, in delicate 2-ranke;l sprays ...119. TAXODIUM DISTICHUM. 

 c 3 . Needle-shaped without distinction of blade and petiole short, about 

 1 in. in length, soft and in fascicles of many each. 



23. LARIX AMERICANA. 



