ICO 



BOTANY. 



ing less perfectly developed tissues and tissue systems. Their 

 epidermal system is more feebly developed, and they bear very 



Fig. 137. Longitudinal section through the apex of a root of Indian corn (Zea 

 mate). All within and above the line , , v, is the root proper, all below and ontnide 

 of it is the root-cap, or ptleorhiza ; , apex of root ; e, e, epidermis, continued into 

 the dermatogen at the apex ; v. v. the thickened outer wall of the epidermis (the 

 origin of the root-cap from the dermatogen is not shown in this figure) ; sc, r, the cor- 

 tex which if produced from the pcriblem at the apex ; m, g.f, the plerome; m be- 

 comes the pith, g a vessel, f. wood ; a, a. outer and older portion of the root-cap ; i, 

 inner and younger portion 'of the root cap. After Sach*. 



