150 TALKS AFIELD. 



bility of any part of a plant to circum- 

 stances, and as well also of the individuality 

 of these parts, that rootless stem-cuttings at 

 once emit roots and stemless root-cuttings 

 often emit stems. The '' suckers " that arise 

 from the severed roots of apple and pear- 

 trees and the successful propagation of black- 

 berries and other plants from pieces of roots 

 are familiar examples of entirely stemless 

 and budless roots that give rise to stems. 

 Occasionally roots arise from the exposed 

 surfaces of stems, as in the climbing poison 

 ivy ; and here we find a third office of roots, 

 for they are essential aids to the climbing. 

 Indian corn emits peculiar aerial roots from 

 its lower nodes, and in a similar manner do 

 many palms and other tropical plants. 

 These roots enter the ground and serve 

 both as feeders and hold-fasts. In warm 

 countries many plants subsist entirely upon 

 food which is gathered from the air by aerial 

 roots. These are the air-plants, great num- 

 bers of which are members of the peculiar 

 orchid family. One of these is the vanilla 

 plant, which clambers over trees and drops 

 its long, cord-like roots into the humid air. 

 The familiar long-moss which decorates the 

 forests of our Southern States has the most 



