36 SOUTH AFRICAN BOTANY 
outside. A last noticeable feature of the section is a 
layer of cells between the endodermis and the vascular 
bundles, known as the Pericycuz. It forms the outer- 
most tissue of the vascular cylinder, and new lateral 
roots take their origin in this tissue. ; 
23. The Root of the Mealie.—A transverse section of 
Pericycle-~ oe 
Endoderms f 
Cortex---~ 
Epidermis ~ ca 
Fic. 21.—Mealie Root. 
a young mealie root (fig. 21) is very similar to that of 
the bean described in the preceding paragraph. The 
xylem bundles are more numerous, however, varying 
from twelve to twenty, or more. 
No secondary thickening takes place in monocoty- 
ledonous roots. Secondary thickening occurs in most 
dicotyledonous roots. 
