FALL OF THE LEAF. 149 



particular temperature upon the junction, but an 

 action of the whole plant. Yet in the whole plant it 

 may be modified by other circumstances. The beech 

 that wears the russet livery of winter, and that through 

 the bare twigs of which the wind howls, are not diffe- 

 rent varieties ; for any one who has the opportunity of 

 examining beech woods may find the aged tree quite 

 bare, and the sucklings around the root clad in their 

 hard and lifeless foliage. And even those lateral 

 branches that form upon the trunk of the beech by the 

 accumulation of a ganglion in a cell of the bark, at 

 the termination of one of the radiating plates or fila- 

 ments that extend from the centre of the tree, may be 

 seen with its leaves on, after the greater part of the 

 head has been denuded. The formation of those 

 woody ganglions is, in itself, a curious matter. They 

 are peculiar to trees that have well defined radiations, 

 though they are not found upon all of these ; and they 

 are never found upon trees the wood of which has only 

 concentric rings, such as the pine. There is a medullary 

 thread from the pith of the tree to the ganglion ; and 

 the latter, even when not the size of a small pea, is 

 hard and fibrous, the fibres being wound round centres 

 from which the future branches are to issue. Though 

 covered by the epidermis and external bark of the tree, 

 those little knobs are surrounded by a liber of their 

 own, at every point, except that by which they are 

 attached to the medullary thread. Wood of this kind is 

 always much more easily split upon a radius than in 

 any other direction, and that which wants the rays is 

 always most easily split in the lines of the concentric 

 rays. By dexterous management, a portion of young 

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