THE LIVING WORLD 



203 



the different "tissues" whereof the entire plant is 

 made up. 



The fern consists of an axial portion corresponding to 



the stem of most plants, which runs along underground, 



giving off at intervals the parts which appear above 



ground and are called fronds. These fronds correspond 



FIG. 34. 



BRACKEN-FERN (Pteris aqidlino). 



Showing fronds springing from underground stem, which gives 

 out rootlets beneath. 



with the leaves of ordinary plants ; and all leaves, however 

 modified, are distinguished, by the term foliar organs, 

 from stems, which, however modified, are called axial 

 organs. Roots, in the form of filamentary processes, 

 are given off from the under surface of the creeping 

 subterranean stem or rhizome. The latter is formed 



