CH. I. 



BY THE SUKFACE OF THE KOOTS. 



27 



the ends of 

 roots a 

 fallacy. 



branches, the greater part of the rain which falls upon ends of 



branches 



the tree is made to drop from the leaves at the exact Jrip on to 



^ the ( 



distance from the trunk where, after it has soaked J'^'^^''' 

 through the earth, it will be received by the extremities 

 of the roots, and readily sucked in by the spongioles.' 

 This is the notion of indoor bookish theorists. I forget 

 who first made the observation, but, as it is repeated 

 by almost all writers on vegetable physiology, it 

 deserves notice. Both the facts here supposed may be 

 considered as vulgar errors. That is, in general, the Branches 



shorter 



horizontal extension of the roots will be found far to than roots, 



and the 



exceed that of the branches ; and so far from its being fhlmxgh 

 true that less water falls under the head of a tree than LtSi^^* 

 outside it, there is every reason to believe that more 

 falls there. 



In reference to the comparative length of the roots 

 and branches, there is doubtless gTcat difference in 

 different trees. But generally it is probable that the 

 aggregate bulk of timber in the root is equal to that of 

 the trunk and head ; and as the roots creep along the Yorm of 

 surface of the earth, they form a flat circle like a flat d?cie 



like a 



wheel round a single tree, instead of a spherical circle ^^eei : 



^ ' ^ form of the 



like a ball as the head does. Consequently, the roots ^i^^^^^^ 

 make up by their horizontal length for their want of a blu.^^^^ 

 opportunity to shoot perpendicularly either upward or 

 downward. Those who will not trouble themselves to 

 dig for this truth, may see it in trees which are apt to 

 throw up suckers, such as the elm or aspen. Suckers 

 may be seen from these at four, or perhaps T might say 



