CATKIN TRIBE; OAK, CORK. 



503 



The ovarium will be found carefully inclosed in the scales of 

 which the bud consists, and protected by a quantity of soft hair. 

 The ovarium contains two cells, with an ovule in each ; but only 

 one of these usually comes to perfection. The fertilisation of 

 the seed is insured by the immense quantity of the pollen dis- 

 charged from the numerous anthers, which settles upon every- 

 thing around as a fine dust. Each pistil has a sort of imperfect 

 calyx arising above the ovary, the remains of which may be 

 traced at the point of the nut ; but it is also inclosed in an 

 involucrum of bracts, which increases as the fruit ripens, and 

 almost envelops it, forming the husk of the nut. When the 

 spring is mild, all the ovaria are fertilised, and the nuts ripen in 

 clusters ; but in cold springs it often happens that some of the 

 pistilline flowers are destroyed, so that only single nuts are 

 found in the place of the clusters. In the Oak and Beech the 



calyx is much 

 more definite ; 

 and the involu- 

 crum is very 

 peculiar in its 

 structure, hard- 

 ening into the 

 well-known cup 

 of the Acorn, 

 Beech-mast, &c. 

 The cells and 

 ovules contain- 

 ed in the ovary 



are frequently numerous ; but only one seed usually comes to 

 perfection. 



678. The importance of this order, on account of the valuable 

 timber which it yields, is so well known, that it need not be here 

 dwelt upon. It may be well to mention, however, that in pro- 

 pagating the various species, great care should be taken to select 

 those whose wood is most durable. There is a remarkable differ- 

 ence in this respect, between two species of Oak, which are 

 commonly grown in this country. Of one, which has the acorn- 



Fro. 181. ACORN. 



