THREE DAINTY FERNS 37 



" one-sided " ; the application of the term 

 is explained in the following description. (In 

 some books this species has been called H. 

 Wilsoni, out of compliment to a Mr. Wilson, 

 who is said to have noticed the species first 

 of all.) The Ohe-Sided Filmy Fern. 



Some botanists have considered that the 

 One-Sided Filmy Fern is merely a variety of 

 the former species, though it is generally con- 

 sidered to be a distinct type. The two plants 

 often grow mixed up together and superficially 

 look very much alike ; it is only after a close 

 examination that the differences become 

 apparent. In a general way it will be found 

 that in the case of the One-Sided Filmy Fern 

 the fronds are somewhat more narrow than 

 those of the Tunbridge Filmy Fern. The chief 

 point of distinction is indicated in the popular 

 name : if the pinnae are closely examined it 

 will be seen that the upper portion is much 

 more divided than the lower side. Another 

 distinctive point to which attention should be 

 drawn is that in this species the pinnae show 

 a marked tendency to curve backwards. 



A study of the fertile leaf of the One-Sided 

 Filmy Fern will also give us an additional 

 point in the identification. With a magnifying 

 glass it is plainly seen that the margin of the 

 cup-shaped receptacle into which the sporangia 

 are gathered has not the toothed border to be 

 found in the case of the Tunbridge Filmy Fern. 



As has been indicated, we may look for the 

 One-Sided Filmy Fern in exactly similar 

 situations to those which suit the Tunbridge 

 Filmy Fern. The former species is said to be 

 more common in Scotland and Ireland than 

 the latter. The One-Sided Filmy Fern is, of 

 course, an evergreen. 



