By Leafy Ways. 33 



not twenty oaks are known in England on which it 

 grows in our time. 



Mistletoe is particularly partial to the apple, but it 

 grows freely on the hawthorn, poplar, mountain ash, 

 and many other common trees. It is easily propagated 

 by crushing a berry into a crevice of the bark. 

 (The oak is very subject to the ravages of insects, 

 sometimes hardly a sound leaf can be found on the 

 whole tree. Among its enemies are various flies, 

 which, by making punctures in which to deposit their 

 eggs, produce oak-apples, and similar growths on the 

 twigs and leaves. One of the commonest, or at least 

 most familiar, is the ' nut ' or ' Spanish ' gall used in 

 making ink; but it is not native here, and has not 

 been long known in England. 



The fly which causes the bright red ' currant ' galls, 

 so conspicuous in the early summer, furnishes an 

 instance of that strange phenomenon called alternation 

 of generation. These galls in their present state con- 

 tain grubs, which in time will turn into flies; but 

 these flies will not resemble their parents, and indeed 

 were long classed in a separate genus. The females 

 no males have yet been found deposit their eggs 

 on the underside of the leaves, giving rise to small flat 

 tufts called ' spangles.' The flies which emerge from 

 these spangles will be of the original type, and by 

 puncturing the tree will again produce ' currant ' 

 galls. } 



By the time the foliage is at its best ; when, lit with 



3 



