FIG. 149. A group of leaves and acorns illustrating some of the differences 

 between six species of oak (Quercus) 



A, the white oak (Q. alba) ; S, the red oak (Q. rubra) ; (7, the bur oak (Q. macro- 



carpa) ; D, the black oak (Q. velutina) ; E, the blackjack oak (Q. marylandica) ; 



F, the live oak (Q. mrginio.no). The acorns are about three fourths natural size 



and the leaves less than one half natural size. Modified from R. B. Hough 



157 



