BLADDER TERNS. 



97 



or genera ; but if care be taken to examine tlie form of 

 the covering before jumpiag to a hasty conclusion, no 

 mistake is likely to be made. They are exceedingly deli- 

 cate and fragile in their nature, and are therefore some- 

 times called Brittle Ferns. The three indigenous species 

 are : 



Brittle Bladder Fern. — Fronds spear-shaped, 

 branched in a feathery manner ; leaflets notched at 

 the margin; 



Eotal Bladder Fern. — Fronds spear-shaped, 

 branched in a feathery manner ; leaflets deeply cut 

 into lobes ; 



Mountain Bladder Fern. —-.Fronds triangular, 

 branched; the branches bearing smaller secondary 

 branches, on which are the leaflets {tri-pinnate), 



BEITTLE BLADDEE FEEN.^ 



This is the most common of the Bladder Ferns, and 

 grows in tufts sometimes nearly a foot high, though usu- 

 ally about 6 or 8 inches. The foot-stalk is very brittle, 

 and is bare through half its length, except a few scattered 

 scales at the base. The outline of the leafy portion is 

 spear-shaped. The branches are usually at some distance 

 apart, though in one or two varieties crowded together. 

 The outline of the branches is gradually tapering out- 

 wards, and the leaflets are of a long egg shape, deeply 

 cut into narrow lobes, or notched at the edges. The tufts 

 of spore-cases are often numerous, rounded, and at first 

 distinct ; but by spreading till they meet each other, the 

 under surface of the fronds occasionally appears to be com- 

 pletely covered with the spore-cases. (Plate XI., fig. 2.) 



It is not an uncommon circumstance for the under sur- 

 face of this fern to be sprinkled with the orange pustules 

 of a kind of parasitic fungus, to which we have already 

 alluded. 



The Brittle Bladder Fern is found in moist rocky situa- 



* Cystopteris fmgilis, Beenh. 



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