200 PKACTICAL BOTANY. 



stant, i.e., one corner is directed towards the older part 

 of the root, while the side opposite that corner, i.e., 

 the anterior face or base of the cell, is at right-angles 

 to the axis of the root. 



2. That around the apical cell are regularly arranged 

 Segmental cells, which have successively been cut off 

 from it by walls parallel to the sides of the apical cell- 

 Of these 



a. Those successively cut off from the base form the 

 Root-cap, dividing up by regularly arranged walls into 

 a mass of regular cells. 



5. Those cut off from the sides of the apical cell 

 form the body of the root : these also divide by walls 

 in regular succession. Observe carefully the arrange- 

 ment of these walls, and by comparison of several 

 sections ascertain their order of succession, and their 

 relation to the various tissues of the root above 

 described. 



XVI. Cut successive transverse sections of the apex 

 of a root which has been hardened in alcohol. (This 

 may easily be done if the root be held between pieces 

 of pith, or by embedding in cocoa-butter.) If possible 

 keep all the sections in their proper order of succession, 

 and mount in glycerine. Examine with a low power, 

 and choose out those in which the large apical cell is 

 to be seen. Observe carefully 



1. The form of the apical cell, apparently three- 

 sided : combining this result with that obtained by 

 examination of the longitudinal sections ; the form of 

 the whole cell must be a three-sided pyramid. 



2. The Segments are arranged in regular order round 

 it, and are cut off successively from the three sides. 



