148 TALKS AFIELD. 



called root-hairs, (a, Fig. 97.) These root- 

 hairs are prolongations of the root cells, as 

 shown, much enlarged, at h, Fig. 97. They 

 are the most active agents in the absorption 

 of food, and upon thrifty plants they are al- 

 ways very numerous. The tearing off of 

 these root-hairs is one reason why plants 

 suffer so much from careless removing and 

 transplanting. 



As fast as the roots become stiff and hard 

 the root-hairs die, and those portions of the 

 roots no longer gather food for the plant ; 

 they become constantly more rigid, and after 

 a time partake more or less of the nature 

 of the stem from which they grow. They 

 now perform the second office of roots, that 

 of hold-fasts or anchors to keep the growing 

 plant in position against wind and frost. 

 As roots have fewer offices to perform than 

 stems, and as their environments are less 

 diverse, they do not generally vary widely 

 one from another in different species of 

 plants. They are much simpler in structure 

 than stems, and it is only when they are old 

 that they begin to take on many of the 

 features of the stem to which they belong. 

 Young roots, whether of endogens or exogens, 

 agree in possessing an endogenous structure , 



