38 BEITISH OAK GALLS. 



while fi'om a sapling of about two years' growth the 

 author obtained in 1898 several leaves 06 cm. long 



o 



and 19 cm. wide. 



Many leaves also are long and very narrow, Avitli 

 entire margins and a blunt extremity. 



Although the general hue of the upper-surface of 

 the leaves towards the close of summer is dull l^rown, 

 this colour often changes either wholly or in patches 

 to a warm russet-ljrown, with blotches of yellow, light 

 orange, and red. Specimens that have had large 

 numl^ers of galls of the genus Neuroterus upon them 

 show these colours to perfection, especially noticeable 

 in the case of galls caused by N. mimismatis. 



Leaves from which there is a total absence of chloro- 

 phyll do not bear galls. 



On young trees and brushwood the withered leaves 

 often remain until the following spring, when the 

 growth of new wood and expanding buds causes them 

 to fall off. 



Two other species of Quercus may also l)e briefly 

 described, since they are referred to in subsequent 

 pages : 



(1) The Turkey oak, Q. cerrU (Plate IV, div. A). 



It is a tall, graceful tree with long, narrow, deeply- 

 notched, dark green leaves, which have a petiole of 

 medium length. The acorns are large, ovoid in shape, 

 about half of which is enclosed in the cupule. The 

 interior of the cupule is silvery- white ; the exterior is 

 covered with scales which are very long (12 to 15 

 mm.), and very numerous (as many as 400), and 

 yellowish-green in colour. 



This oak was introduced into England by Miller 

 about the year 1735. It is now somewhat commonly 

 distributed over Britain, and as it flourishes in nearly 

 all soils, and groAvs twice as fast as Q. roJmr it is a 

 good and useful species in parks, plantations, etc. 

 The wood is good, but it is not so heavy as that of 

 Q. robur. 



In some seasons enormous numbers of acorns are 



