KEY, BASED UPON FLOWEKS. 5 



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. 



I*. Lanceolate to oblong, sharply undulate-toothed 



68. Q. MUHLENBERGII. 



J 2 . 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, oblong, entire or undulately 



spinose-toothed 161. Q. CHRYSOLEPIS. 



h 1 *. Styles elongated ; stamens 4-6 ; abortive ovules superior 



(subsec. Melanobalanus (BLACK OAKS). 

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



ately spinous-toothed or entire 138. Q.AGRIFOLIA. 



i 2 . Maturation usually biennial ; leaves 



?. Deciduous and with teeth and lobes acute and bristle- 

 pointed ; 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. 

 A; 2 . Deeply pinnatified ; lobes 



Rather broad ; inner bark yellowish 



93. Q. TINCTORIA. 



Narrow ; sinuses broad and rounded ; acorn ovoid- 

 oblong, i invested in a coarse-scaled cup. 



69. Q. COCCINEA. 

 j*. Flattened-globular, invested in fine-scaled cup. 



94. Q. PALUSTRIS. 



j z . Leaves subpersistent (part persisting and green throughout 



the winter) ovate-spatulate globuous. .118. Q. AQUATICA. 



gr j . Erect with pistillate flowers at their bases ; stigmas linear; leaves 



persistent (section Pasania) 50. Q. DENSIFLORA. 



f 1 . 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. 



/ 3 . Involucre 4-valved and inclosing two 3-cornered edible nuts. 



16. FAGUS FERRUGINEA. 



e 3 . Fertile flowers 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. 



e? 2 . Both staminate and pistillate flowers in catkins. 

 e. Ovary and pod 2-celled, many-seeded. 



60. LlQUIDAMBAR STYRACIFLUA. 



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

 /". Not becoming succulent in fruit ; fertile flowers 

 g. Two-three at each scale of the catkin ; calyx 

 h. Very irregularly 4-lobed, stamens 2 ; scales of cone thin and 



deciduous (Betula) ; bark 

 i Brown and close, catkins erect 44. B. LENTA. 



1 2 . Yellowish-gray and ragged, catkins sub-erect. . .17. B. LUTEA. 



1 3 . White, and leaves 



Deltoid, smooth both sides 70. B. POPULIFOLIA. 



Ovate, hairy on veins beneath 43. B. PAPYRACEA. 



i\ Reddish-brown, shaggy 95. B. NIGRA. 



h?. Four- parted ; stamens usually 4 ; fertile scales thick, woody 



and persistent (Alnus) 163. A. RHOMBIFOLIA. 



gr*. Single at each scale of the catkin (Myrticaceaz); flowers monoe- 

 cious 164. MYRICA CALIFORNICA. 



