THE CHAIN FERNS. 221 



pinnule, and another series of larger sori parallel with the 

 midribs of the pinnae. They appear as if partly sunk 

 in the tissues of the frond and are covered with a 

 leathery indusium as with a lid. It does not require 

 a very lively imagination to see in the oblong sori 

 placed end to end a resemblance to the links in a chain 

 and the common name is therefore quite appropriate. 

 From its delight in mud and water, it is sometimes 

 called the bog fern. This species is also illustrated in the 

 Key to the Genera. 



The chain fern is found from southern Canada to 

 Florida, Louisiana and Michigan and also in Bermuda. 

 It is frequently found growing in several inches of water 

 near the coast where it is often so abundant as to al- 

 most fill the swamp, like a field of grain. Inland it is 

 likely to be found in sphagnum swamps among 

 Pogonias, pitcher-plants and other semi-aquatic vege- 

 tation. According to Eaton, the fronds may face in any 

 direction in bushy swamps, but when they are exposed 

 to the sun, all face toward the south. It is an excellent 

 species for cultivating on the borders of artificial lakes 

 in the fern garden. On the western coast of America, 

 there is a tall and robust species W. radicans which is 

 much like ours in general appearance, but is darker 

 green in colour. This is the only western species and is 

 widely distributed in other parts of the world. 



The Narrow-Leaved Chain Fern. 



Like its relative, the narrow-leaved chain fern (Wood- 

 wardia angustifolid) has the misfortune to resemble a 

 more plebeian species. This species is the sensitive fern 

 and the resemblance, as in the case of the other, extends 



