THE BRACKEN-FERN. 



Pteris aquilina. 



PTERIDOPHYTES; FILICALES; FILICINE^l. 



PRELIMINARY. 



THIS fern is general in its distribution, being found 

 under a variety of conditions. The leaves stand erect 

 from an underground stem, and branch rather exten- 

 sively. They sometimes become three or four feet long 

 and often develop in such numbers as to produce quite 

 dense growths. The underground stem is sometimes 

 many feet long, and may have leaves arising from its 

 tip and from many side branches. On the under side 

 of leaflets the sporangia appear, being protected by a 

 fold of the leaf margin, and when ripe appear reddish 

 brown. 



Occasionally one may find the gametophytes on damp 

 earth near the adult plants. They may range in size 

 from one or two millimeters to one or two centimeters 

 across. They are irregularly heart-shaped and are held 

 close to the soil by a system of rhizoids that arise from 

 the lower surface of the gametophyte body. In some 

 cases a primary leaf of a young sporophyte may be seen 

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