THE ROOT. 



69 



cells as the growth of those behind constantly pushes the 

 apex forward through the soil. 



In seed-jjlants, the segments of the egg which produce the 



Fig. S4. — 1 ransveT'se section of a yoaiiLr root thrown in soil, showing root-hairs with 

 adherent soil-particles, the eorte.x', and the stele. Magnified about 20 diam, — After 

 Franli. 



root do not divide so as to form a single apical cell, but a 

 group of initial cells, which retain the power of ra]iid di\ision 

 and constitute a primary nieristem or growing point. In all 

 other respects the development of tlie root from this group 

 of initials is similar to that already described. 



