THE ANGIOSPERMAE : ROOTS 831 



This suggestion of the origin of roots obviously leaves to be explained 

 much that we consider typical of roots, especially their endogenous branching 

 and the presence of a root cap. It is worth remark, however, (i) that the 

 primarv root itself is not endogenous and that lateral roots are not invariably 

 so, notably in the primitive Lycopods, both living and extinct ; (2) that the 

 formation of roots is restricted in the more primitive vascular plants to the 

 base of the leafy shoots ; and (3) that many instances are known of roots 

 without a root cap. 



Examples of the absence from roots of every individual one of the so-called 

 typical characters can indeed be quoted, except, perhaps significantly, that of 

 leaflessness. Under the concept of their origin here put forward this is only 

 to be expected, since leaflessness would be a basic character common to all 

 branches alike, in the primitive dichotomous body. It could be argued that 

 it is the presence of leaves on the aerial stem, not their absence from the root, 

 which is the acquired character. 



