5o6 



A TEXTBOOK OF THEORETICAL BOTANY 



The points on the rhizome at which the leaves are given off are termed 

 the nodes, whilst the spaces between the nodes are called internodes. In 

 the Male Fern the leaves are set so closely together in succession that there 



Fig. 498. — Pteridium aquilinuni. Apex of rhizome 

 with three successive stages in the development of 

 leaves. 



Cortex 



Merlstelt of outer 

 ring 



Meristele of inner 

 ring 



Sderenchyma 



Fig. 499. — Pteridium aquilimau. Transverse section of 

 the rhizome showing two concentric rings of meri- 

 steles separated by two arcs of sderenchyma. 



are no internodes on the stem. In the Bracken the internodes are long, and 

 on this account it is easier to study the anatomy of the stem of the Bracken 

 than that of the Male Fern. 



