Plate IX. 



FIG. 21. Transeetion of the root of Spirantht* cernua. Showing the general 

 structure of the root with the relations of the various parts. A, root hair: H, 

 x>lem of the radial bundle; <', phloem, alternating with the xylem areas; I), epi- 

 dermis of the root; E, pith; F, bundle sheath or endodermis; G, cortex; II, inter- 

 cellular space. (x50.) 



FIG. 22. The radial bundle in Fig- 21, more highly magnified. The lettering is 

 the same In both figures. (xlOO.) 



