KEY, BASED UPON LEAVES. 3 



g, Subequal, sinuses 



Wide, lobes narrow and nearly entire ; leaves 5-9 in. long. 



38. QUERCUS ALBA. 



Narrow, lobes wide and 

 mostly undulate or crenate- toothed ; leaves 2-3 in. long. 



160. Q. LOB ATA. 

 Entire or nearly so and round or obtuse at apex. 



136. Q. GARRYANA. 



gr 2 . Very unequal, 

 h. The two lobes nearest 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 midrib and more acute. 



66. Q. BICOLOR. 



/*. Acutish and mucrpnulate . .216. QUERCUS MACDONALDII. 



f 3 . 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, i 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\ 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^GUS COCCINEA. 



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



82. PRUNUS CERASUS. 

 e 10 . Obscurely crenulate- toothed : leaves 

 f. Alternate, petioles long, mostly \i in. or more. 



87. CORNUS ALTERNIFOLIA. 



/ 2 . Opposite, petioles short (less than 1 in.); involucral scales when fully 

 developed. 



Obcordate 88. CORNUS FLORIDA. 



Pointed at apex 185. CORNUS NUTTALII. 



e 11 . Undulate-serrate, ^- in. long and bearing large scattered glands. 



154. DALEA SPINOSA. 

 e 12 . Doubly serrate. 



Rhombic-ovate 81. PRUNUS NIGRA. 



Ovate-oblong 210. CRAT^EGUS DOUGLASII. 



e n . Creriately lobed; lobes glandular dentate 217. ALNUS OREGONA. 



<P. Main ribs several, palmately-veined, etc. ; rib 

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



3-lobed, 2-lobed and entire on same tree 32. SASSAFRAS OFFICINALE. 



e 2 . Ribs three at first, but soon five or more 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 . 5-7 from commencement ; leaves 



e 4 . 7-9-ribbed and lobed, suborbicular 203. ACER CIRCINATUM. 



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



