4. Leaves of 2 forms, either 3-lobed at apex or deeply 5-1 1 



lobed, 6-8 inches long 



Q. falcate, Southern Red Oak, p. 195. 



3. Leaves green below. 



5. Leaves dull, 7-1 1 lobed, with sinuses extending about V^ 

 way to midrib; acorn enclosed in cup-shaped to shallow 

 (var. maxima) cup. .Q. rubra, Northern Red Oak, p. 193. 



5. Leaves lustrous, mostly 5-7 lobed, sinuses extending more 

 than Vi way to midrib. 



6. Acorn cup shallow, covering only the base of the acorn, 



7. Leaves 6-8 inches long; acorns %-l}/4 inches long, 

 oblong Q. shumardii, Shumard Oak, p. 195. 



7. Leaves 2V^-6 inches long; acorn not over Vi inch 

 long. 



8. Leaves 4—6 inches long; acorn hemispheric, Yi 

 inch long Q. palustris, Pin Oak, p. 199. 



8. Leaves 2V^ inches long; acorn ellipsoidal to 



globose, Vs-Vi inch long; only in Georgia 



Q. georgiana Curtis., Georgia Oak 



6. Acorn cup covering at least the basal V4 of acorn. 



9. Acorn cup with loosely imbricated scales, forming 

 a free margin on rim; winter buds woolly or red 

 hairy. 



10. Leaves usually 7-lobed; winter buds tomentose 

 Q. velutina, Black Oak, p. 193. 



10. Leaves usually 5-lobed; winter buds rusty, 

 pubescent Q. laevis, Turkey Oak, p. 201, 



9. Acorn cup with tightly imbricated scales; winter 

 buds not woolly or red hairy. 



1 1 . Buds white hairy ; acorn with rings near apex, 

 V2-\ inch long Q. coccinea. Scarlet Oak, p. 197. 



1 1 . Buds not white hairy ; acorn without rings. 



12. Acorn ellipsoidal, V^-% inch long; Lake 



states 



Q. ellipsoidalis. Northern Pin Oak, p. 199. 



12. Acorn oblong, %-lH inches long; lower 



Mississippi Valley 



Q. nuttallii, Nuttall Oak, p. 199. 



2. Leaves 3-lobed at apex or entire. 



13. Mature leaves distinctly hairy below. 



14. Leaves gray to rusty woolly below, of two types; acorn 

 Yz inch long, enclosed for Yi or less of length in thin 

 cup Q. falcata, Southern Red Oak, p. 195. 



14. Leaves tawny hairy below and scurfy; acorn H inch 



long, enclosed for Yi-Yi its length in thick cup 



Q. marylandica, Blackjack Oak, p. 197. 



13. Mature leaves glabrous and green below; acorn enclosed 

 for Vi or less of length in thin cup. 



[177] 



