KEY, BASED UPON FLOWERS. 5 



i. Annual ; nut glabrous inside; abortive ovules basal; 

 J. Leaves falling in autumn, 

 h. Sinuate-pinnatifid. 



I. Obovate-oblong, pale below and with 



tn. Narrow oblique lobes 38. Q. ALBA. 



W 2 . Wide lobes, less oblique and margin of lobes 



Undulate- toothed 160. Q. LOBATA. 



Entire or nearly so 136. Q. GARRYANA. 



I I . Obovate with deep sinuses and the central pair of lobes usually 



wide and spreading 93 Q. OBTUSILOBA. 



Jc. Lyrate-pinnatifid ; nut or more immersed. 



"Peduncles shorter than petioles 39. Q. MACROCARPA 



Peduncles longer than petioles 66. Q, BICOLOR. 



k 3 . Coarsely undulate-crenate-toothed (CHESTNUT OAKS) 

 I. Obovate-oblong with mostly rounded teeth ; 



Acorn less than 1-in. long 67. Q. PRINUS. 



Acorn more than 1-in. long 116. Q. MICHAUXII. 



P. Lanceolate to oblong, sharply undulate-toothed 



68. Q. MUHLENBERGII. 



j-. Persistent, dark green, elliptical or oblong and entire or remotely 



spinose-dentate 117. Q. VIRENS. 



i 2 . Biennial ; nut tomentose inside ; abortive ovules basal or lateral ; 

 leaves persistent, both entire and undulately spinose-dentate. 



Oblong, finally glabrous beneath 161 . Q. CHRYSOLEPIS. 



Oblong-lanceolate, tomentose beneath 191. Q. TOMENTELLA. 



h*. Styles elongated ; stamens 4-6 ; abortive ovules superior (subsection 



Melanobalanus BLACK OAKS). 

 i. Maturation annual ; leaves persistent, orbicular-oblong, simiately 



spinous-toothed or entire 138. Q.AGRIFOLIA. 



t 2 . Maturation usually biennial ; leaves 

 y. Deciduous and with teeth and lobes acute and bristlepointed ; 



leaves 

 k. Moderately pinnatifid 



Cup very shallow, covering the nut ; scales fine. .15. Q. RUBRA. 

 Cup deeper, - covering the nut ; scales large. 



162. Q. CALIFORNICA. 

 7c 2 . Deeply pinnatified ; lobes 



I. Rather broad ; inner bark yellowish 93. Q. TINCTORIA. 



I I . Narrow ; sinuses broad and rounded ; acorn 



Ovoid-oblong. \ invested in a coarse-scaled cup. 



69. Q. COCCINEA. 

 Flattened-globular, invested in fine-scaled cup. 



94. Q. PALUSTRIS. 

 j 2 . Subdeciduous part persisting and green throughout the winter 



obovate-spatulate glabrous 118. Q. AQUATICA. 



j 3 . Persistent, oblong-lanceolate 192. Q. WISLIZENI. 



</ 2 . Erect, with pistillate flowers at their bases ; stigmas linear; leaves 



persistent (section Pasania) 50. Q. DENSIFLORA. 



/*. Involucre 2-4-valved, becoming hard and prickly and inclosing 1-3 

 sweet, edible, flattened, subglobose nuts ; sterile flowers in catkins ; 

 leaves 



Deciduous 40. CASTANEA VESCA. 



Evergreen 139. CASTANOPSIS CHRYSOPHYLLA. 



f' A . Involucre 4-valved and inclosing two 3-cornered edible nuts. 



16. FAGUS FERRUGINEA. 



e 3 . Fertile flower? in short catkins ; nuts small and achenium-like ; sterile 

 flowers destitute of calyx ; leaves simple. 



/. Nutlet inclosed in a bladder-like bag 41 OSTYRA VIRGINICA. 



/ 2 . Nutlet not inclosed but subtended by an enlarged leafy bract. 



42. CARPINUS CAROLINIANA. 



(I 2 . Both staminate and pistillate flowers in catkins. 



e. Ovary and pod 2-celled, many -seeded ... 60. LIQUID AMBAR STYRACIFLUA. 

 e 2 . Ovary 1-2-celled with a single ovule in each cell ; calyx of fertile flower 



