Ferns : Habitats, Life-Story, Morphology 



leafstalk, the stem, and its branches, the leafstalks of 

 separate leaves, but because we know the real stem is 

 underground we can understand why the frond of the 

 oak-fern is looked upon simply as a leaf cut into three 

 main divisions, or, in other words, as a trifoliate leaf. 



When the fern-leaf first emerges from the soil it is 

 coiled or rolled up in such a way as to resemble a 

 shepherd's crook or a bishop's crosier. Of course we 

 cannot fail to notice how effective this arrangement is 

 as a protection to the delicate tissues of the fronds 

 when they are forcing their way upwards through the 

 ground. When once clear of the soil the leaf begins 

 slowly to uncoil and to straighten out. Only two 

 British ferns the Adder's Tongue Fern and the 

 Moonwort Fern do not have their young fronds 

 rolled up in this fashion. In the case of both of these 

 ferns, the fronds are, before being expanded, folded at 

 right angles to the midrib, and so folded they push 

 their way through the soil. 



In describing ferns, certain terms referring chiefly to 

 the leaf divisions are employed, with the commoner of 

 which it is very necessary that we should be acquainted. 

 Most ferns have very much divided leaves, and very 

 few have uncut or entire leaves. If a fern-leaf be cut 

 almost to the midrib, we call it a " pinnatifid " leaf, and 

 when this cutting extends right down to the midrib, so 

 as to divide the frond into separate segments or leaflets, 

 each leaflet is called a " pinna," and the whole frond is 

 described as " pinnate." If each pinna be again cut 

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