504 CORK-TREE. ORDER CONIFERS. 



stalks long, and the leaves short, the timber is cloee-grained, solid, 

 and not liable to rot ; whilst the other, which has the acorn-stalks 

 short, and the leaves long, affords a wood of much looser texture, 

 very apt to decay. The former is the Old English Oak, of 

 which those ancient fabrics are constructed, that have resisted 

 the ravages of time for many hundred years. The latter was 

 probably introduced from the Continent about three hundred 

 years since ; and being more easily propagated, and of quicker 

 growth than the other, it has been latterly substituted for it, 

 especially in the New Forest, in the Northern counties, and in 

 the neighbourhood of London. It is not unlikely that the late 

 prevalence of dry-rot in our dock-yards is partly due to this 

 cause. 



679. Next to timber, the most important product of this 

 order is Cork, which is a portion of the bark of a species of Oak 

 common in the South of Europe. This peculiar substance, which 

 consists entirely of cellular tissue, exists in many trees ; but it is 

 most abundantly found, and most quickly renewed, in this one. 

 The cork is first taken off when the tree is about fifteen years 

 old, and the next crop is removed ten years after ; these two, 

 however, are of little value, being thin and full of fissures. 

 Afterwards the operation is repeated every eight or ten years ; 

 and a tree thus barked will live a hundred and fifty years. 

 The importance of the secretions of tannin and gallic acid, which 

 are afforded by the bark, acorn-cups, and gall-nuts of this order, 

 has been formerly dwelt on (. 365 and 399). Willow bark 

 contains a bitter principle, which has been used in medicine as a 

 substitute for that obtained from the Peruvian Bark. The 

 Myrica cerifera, or Wax-plant of North America (. 381), is a 

 species of this order, allied to the Gale or Dutch Myrtle of this 

 country. 



680. The last order to be noticed in this group, differs so 

 remarkably from all the rest, and in fact from all other Exogens, 

 that some Botanists consider it in the light of a separate class. 

 This is the order CONIFERS, all the members of which are dis- 

 tinguished by their fructification ; this having the form of cones, 

 of which those of the common Fir, Larch, &c., are examples. 



