PLANTING. 



and exhibit a numerous series of fragments of rays, filling 1 up the spaces 

 between the primary ones, obvious to the naked eye, and rendering the 

 silver grain, as it is called, of the beech very distinct from any other kind 

 of wood. 



The wood of the Spanish or sweet chestnut (e) has often been con- 

 founded with that of the oak ; but its characters of distinction are very 

 obvious. It agrees with the oak in having the secondary rays equally 

 disposed, almost straight, and, though close to each other, yet not crowded 

 as in the elm and beech; it differs, in the primary rays being scarcely to be 

 distinguished from the secondary, whilst in the oak these are prominent 

 and obvious to the naked eye on the slightest inspection. The concentric 

 layers are regularly curved, whilst in the oak they are strikingly waved. 

 The mouths of the tubular vessels, which constitute so obvious a part of 

 these annual rings, or layers, are disposed in triangular masses in the ouk ; 

 on the contrary, in the chestnut they are in regular order. 



The hornbeam (f) has the rays of the wood nearly equal, but may 

 readily be distinguished from that of the beech, to which it bears the 

 greatest resemblance, by the simple arrangement of the tubular structure 

 accompanying the concentric layers, which in the hornbeam are distant and 

 oval shaped, the narrow sides pointing to the pith and to the bark; in the 

 beech they are circular shaped, more numerous, and equal sized. 



The birch (g) has all the medullary rays nearly equal, arranged closely, 

 and having the concentric circles minute, but marked with a row of equal 

 cells. 



The horse chestnut (A) has all the rays very minute, few of them ap- 

 parently continuous, but interrupted, and in substance varying in breadth. 

 The cells are numerous and minute. 



Alder (i) has the wood with large primary rays, thinly arranged, but 

 in nearly regular order; the secondary rays are slender, numerous, and 

 interrupted. The cells of the concentric layers are nearly a regular. The 

 spaces between the rays are crowded with cells. 



