23 - 



5a. Cup of the acorn saucer-shape, covering less than one-third of 



the acorn 6. 

 5b. Cup of the acorn hemispherical or top-shape, covering one-third 



or more of the acorn 8. 



6a. Length of the lateral leaf-lobes less than one-third the 

 width of the leaf; acorn cup 2 2.5 cm. wide 



Red Oak, Quercus rubra. 



Gb. Length of the lateral leaf-lobes more than one-third the 

 width of the leaf 7. 



7a. Acorn depressed-globose, about 1 cm. in diameter 



Pin Oak, Quercus palustris. 

 7b. Acorn ovoid, 1.5 2 cm. thick Schneck's Oak, Quercus schneckii. 



8a. Leaves pubescent beneath Black Oak, Quercus velutina. 



8b. Leaves glabrous beneath 9. 



9a. Buds glabrous; inner bark of the trunk yellow 



Hill's Oak, Quercus ellipsoidalis. 

 9b. Buds pubescent beyond the middle; inner bark of trunk red 



Scarlet Oak, Quercus coccinea. 



lOa. Leaves deeply pinnately lobed 11. 



lOb. Leaves crenate, dentate, or sinuate, not lobed 12. 



lla. Leaf divided nearly to the middle by a pair of deep lateral lobes 

 near the middle of the leaf; acorn more than half covered by 

 the cup Bur Oak, Quercus macrocarpa. 



lib. Leaf without a median pair of deeper lobes; acorn about one- 

 fourth covered by the cup White Oak, Quercus alba. 



12a. Leaves broadest at or near the middle, with numerous 

 (8 13) sharp coarse teeth on each side 



Yellow Oak, Quercus muhlenbergii. 



12b. Leaves broadest above the middle, with a few shallow, 

 rounded or subacute teeth (7 or less on each side) 13. 



13a. Large tree; leaves densely white-tomentose beneath; acorn on 

 a stalk 310 cm. long Swamp White Oak, Quercus bicolor. 



13b. Shrub; leaves thinly white-tomentose beneath; acorn sessile or 

 nearly so Scrub Oak, Quercus prinoides. 



URTICACEAE, the Nettle Family 



Herbs or trees, with small inconspicuous apetalous flowers. 



la. Trees or tall shrubs 2. 

 Ib. Herbs 7. 



2a. Leaves oblong-ovate to lanceolate, serrate 3. 

 2b. Leaves broadly ovate to rotund, some of them lobed (Mul- 

 berry) 6. 



