THE ABELE. 



Po'pulus al'ba L. 



The two genera Populus, the Poplars, and Sal'ix, the 

 Willows, constitute the Natural Order Salic'acece, 

 a group of catkin-bearing trees and shrubs not 

 very obviously allied to any others. Though vary- 

 ing greatly in dimensions, all of them are perennial 

 woody plants, generally of rapid growth, and pro- 

 ducing a soft white wood. Their leaves are deciduous 

 and undivided, spring singly from the nodes, and are 

 furnished with stipules ; and their flowers are in con- 

 spicuous catkins, the two sexes being on different 

 plants (" dioecious "). This introduces a double diffi- 

 culty into the study of the group, for not only do 

 the staminate and carpellate trees of one species 

 sometimes differ to some extent from one another, but 

 hybrids or cross-bred trees frequently occur in a 

 natural state, and still more frequently where, as in 

 withy-eyots, several kinds are cultivated side by side. 

 The flowers are of a very much simplified type, the 

 "perianth" the calyx and corolla, that is, of an 

 ordinary flower being replaced by simple minute 

 scales. These scales being single i.e. there being 

 but one to each flower in the catkin they are 

 probably really rather of the nature of bracts ; whilst 

 the perianth may be looked upon as altogether absent 

 in Willows, though perhaps represented by a little 

 one-sided, cup-shaped body, called a " disk," in the 

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