86 KEY TO GENERA AND SPECIES 



132. Acorn small, less than of an inch long. 

 Mass, southward and westward. (Fig. 156.) 

 Pin Oak, Quercus palustris Muench. 



.tri 



Fig. 159. Red Oak. 



132. Acorn large, more than of an inch long. 

 Throughout our range. (Figs. 158, 159.) 

 Red Oak, Quercus rubra L* 



*The Gray Oak (Quercus rubra var. ambigua (Michx. f.) Fer- 

 nald), with the fruit of the Scarlet Oak and the foliage' of the Red 

 Oak, occurs along the northern range of the Red Oak and is usually 

 regarded as a variation of that species. 



