76 



THE BIOLOGY OF A PLANT. 



ep. 



FIG. 36. Section showing the epidermis (ep), and the underlying sclerotic parenchyma 

 (s.p) of the rhizome of Pteris aquilina. Canals, sometimes branching, are everywhere 

 seen. 



FIG. 37. Cross-section of sclerotic prosenchyma of the rhizome of Pteris aquilina. The 

 enormously thickened walls consist of three IMV.TS. an- perforated by pores, and are lirj- 

 nified or turned into wood. 



