472. THE STRUCTURE OF ECONOMIC PLANTS 



Development of the Collenchyma. — The mature collen- 

 chymatous cells are small in transection and very much elongated 



Fio. 2.41. A~D, transections of collenchyma in successive stages of development; E, 

 stage showing late initiation of collenchyma; F, longisection of young collenchyma. 

 Stippled areas represent oil ducts. (After Esau, Hilgardia.') 



axially with oblique end walls. The walls are thickened chiefly 

 at the angles, although there are some additional thickenings on 

 the lateral surfaces. (Fig. X4i.) The development of the young 

 strand at first resembles that of a procambial one; and longitudinal, 



