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A TEXT-BOOK OF BOTANY 



though ferns are found in considerable numbers in temper- 

 ate regions, their chief display is in the tropics, where they 

 form a striking and characteristic feature of the vegetation. 

 In the tropics not only are great masses of the low forms 

 to be seen, from those with delicate and filmy moss-like 

 leaves to those with huge leaves, but also tree forms with 



FIG. 178. The staghorn fern, which is an epiphyte. 



cylindrical trunks encased by the rough remnants of fallen 

 leaves and sometimes rising to a height of thirty-five to 

 forty-five feet, with a crown of great leaves fifteen to 

 twenty feet long (Fig. 177). There are also air forms 

 (Fig. 178), that is, ferns that perch upon other plants but 



