TAXONOMY 



317 



(petiole). The margins of the chestnut and beech leaves are sharply 

 cut with large teeth. The leaves of the oaks divide the genus into 

 two groups, viz. the white oaks with rounded lobed leaves and 



PIG. 178. Quercus infectoria Branch and nutgall. (Sayre.) 



annual acorn production, and the 'black oaks with sharp bristle- 

 tipped lobes and biennial acorn production. The male flowers are 

 in dangling heads (beech), or in catkins (chestnut and oaks). The 



