CHAP. CV. CORYLA^CE^.. <iUF/RCUS. 1729 



roots ; and if from the shoots one is selected to form tlie future tree, and the 

 others carefully rubbed off, the tree will advance at as rapid a rate as if it 

 had been sown where it was intended finally to remain ; and, in cases where 

 the subsoil is bad, much more so. 



In the future culture of the oak, the trees generally require side pruning 

 when the object is a straight clean trunk. As most of the species grow erect, 

 the hardier deciduous kinds are well adapted for hedgerows ; but, as many 

 of the American kinds are comparatively tender, they are most advantageously 

 cultivated in masses. The group 7Mex forms excellent evergreen hedges, 

 and most of the species belonging to it endure the sea breeze. The Nepal 

 species, as far as they have hitherto been introduced, require, even in the cli- 

 mate of London, the protection of a wall. 



Accidents, Diseases, Lisecfs, j)arasitic Plants, lS-c. None of the oaks are so 

 liable to have their branches broken by high winds as most other large 

 trees; but, on the other hand, they are said to be more frequently struck by 

 lightning than other broad-leaved trees of the same size, or than needle- 

 leaved trees of any height. The oak is subject to few diseases, notwithstand- 

 ing the many kinds of insects that live upon its leaves. As the greater part 

 of our knowledge respecting the insects which feed on the oak relates to those 

 which infest the species comprising the group ^obur, and those which pro- 

 duce the galls of commerce and the scarlet grain, we shall defer what we 

 have to say on this subject till we come to treat of the species alluded to. 

 The fungi and lichens which live on the oak will be found noticed under 

 the group /?6bur ; and others which are common to trees generally will be 

 treated of in a separate chapter, in Part TV. of this work. Fortunately, though 

 the insects infesting the oak often destroy, injure, or disfigure the leaves, yet 

 there are but very few kinds which attack the solid wood till it is in a state 

 of decay ; in which respect the oak differs widely from the elm, which, as 

 we have already seen (p. 1387.), is liable to have its wood destroyed by the 

 jScolytus at every period of its existence. 



Stud?/ of the Species. Till the oaks of America began to attract the notice 

 of botanists, the European species occasioned comparatively little difficulty. 

 The American sorts, however, vary so exceedingly in their leaves at different 

 seasons of the year, in different stages of their growth, and in different lo- 

 calities, that it is next to impossible to fix on a specific character, taken from 

 them, which shall remain constant. The descriptions of the American oaks 

 which have been published are, consequently, of very little use, without 

 figures ; and even the figures differ exceedingly in different authors : for 

 example, in the works of the younger and elder Michaux, in Abbott's Insects 

 of Georgia, in Catesby's Carolina, and in Audubon's Birds of Awerica] not to 

 speak of the figures in the Nouvcau Dii Hamel, and other works published on 

 American oaks by botanists who have not been in America. 



All the species of oaks hitherto described by botanists have been arranged 

 in sections founded on a single character taken from the leaves. Willdenow, 

 for example, has arranged them in the five following sections : such as, 1. 

 Leaves entire ; 2. Leaves toothed ; 3. Leaves lobed ; 4. Leaves sinuate, with 

 the lobes mucronate ; and, 5. Leaves sinuate, but the lobes without any 

 mucros. This arrangement, which has been followed by Smith, and in the 

 Nouveau Du Hamel and other works, has, like all others of the kind, the dis- 

 advantage of bringing together species which are not allied in perhaps any 

 other particular than that which characterises the section. Thus, in all 

 Willdenow's sections, evergreens are indiscriminately mixed with deciduous 

 kinds ; large-leaved, rapid-growing, lofty trees, with small, slow-growing, bushy 

 trees; and so on. We do not mean to say that this arrangement is without 

 its use ; but we think it decidedly inferior to one in which the species are 

 thrown into groups according to a totality of characters. Such a classification 

 cannot, in the case of this genus, in our opinion at least, be effected satisfac- 

 torily either from dried specimens or drawings ; and, therefore, till the whole 

 of the species have been seen in a growing state by one botanist, it cannot 



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