300 



A TEXT-BOOK OF BOTANY. 



Lemna, etc. If we take a germinating plant and mark the root 

 into ten equal divisions, beginning at the apex, and place the 

 plant in a moist chamber, it will be found in the course of one 

 or two days that the marks between i and 5 have become much 



Fig. 162. Longitudinal section through the tip of the root of Indian com (Zea Mays) 

 showing root-cap: a, outer layer; i, inner layer. — After Sachs. 



farther apart, and that the growth in this region is about three 

 times that between 5 and 10. This experiment indicates that the 

 growth of the root takes place at or near the apex, this region 

 being known as the point of growth, or point of vegetation (Fig. 

 162). 



