166 THE OAK 



their eggs in the young tissues of various plants, espe- 

 cially oaks and roses. 



Some of the resulting galls are discoid, such as the 

 'oak-spangles' of our woods ; others, again, are spherical, 

 such as the common leaf-galls so well known in England, 

 and the so-called oak-apple ; then there are the ' arti- 

 choke galls,' produced by the partial metamorphosis of 

 the buds of the oak in which the cynips has laid its 

 egg, and many others. 



