DICOTYLEDONE^E. 67 



The early development of the catkins in the 

 spring- has been already adverted to ; and it may be 

 added, that their sudden and conspicuous appearance 

 on the poplar and willow, have the effect of even 

 changing- the face of the country where such trees 

 abound. 



The Qucrcus is the most important genus in the 

 group, and this, together with Fagus and Cdstanea, 

 yield valuable nuts, useful as food for both man and 

 beast. The Platanus Orientdlis is no less curious in 

 its mode of seeding, than remarkable for discharging 

 its bark at a certain stage of its growth or age. 



The interior structure of the Amentacece is in all 

 of them very similar, differing only in the pon- 

 derosity, tenacity, and durability of their timber. 

 That of the Salix and Populus is soft and quickly 

 perishable when exposed to the weather; the Fagus 

 and Carpinus have wood of a mild texture and dense 

 grain, and that of the Quercus and Castanea is rigid, 

 heavy, and durable. 



The longevity of the trees in this order is more 

 or less extended. Willows generally begin to decay 

 sooner than any other. Alder is also comparatively 

 of short duration. The Spanish chestnut and oak 

 endure for many years. But there is a period of 

 perfection incident to every tree, which has not been 

 sufficiently studied by phytologists, and which well 

 deserves attention. 



All vegetable matter, when left to nature, is des- 

 tined to decay after being deserted by the vital power 

 * 2 



