THE ROOT 191 
THE ANATOMY OF ROOTS 
General regions. The general internal structure of stems and 
roots is very similar. In both cases there is a central stele 
which is surrounded by a cortex (Figs. 187, 188). In stems 









oH Beez 
sy 38 [} OD 
2 ET TL 
sane ceres TS AERO {) CD 
ee. 
eS, 
CSI a se 










Fic. 188. Cross section of root of a species of Wandering Jew (Commelina), 
| a monocotyledonous plant 
e, epidermis ; c, cortex; en, endodermis ; pa, passage cell ; pe, pericycle ; 
ph, phloém; z, xylem. (x 55) 
this is in turn surrounded by an epidermis. Some authorities 
maintain that in roots there is no true epidermis, but that this 
structure is represented morphologically in the formation of the 
primary rootcap. Others, however, contend that the outermost 
layer of the root is morphologically an epidermis, but that it is 
not such physiologically, as it is an absorbing and not a pro- 
tective structure. These theoretical considerations need not 

