142 FERNS OP GREAT BRITAIN. 



From tliese tubers descend a number of long, tubular, 

 somewhat pellucid roots, which are sometimes forked 

 at their extremities. Some botanists have eaten these 

 tubers when young, and consider them to be perfectly 

 innoxious, though having an earthy flavour. The 

 leaves, which arise from the crown of the tuber, are 

 of a somewhat olive-green colour, very brittle, and from 

 four to seven inches long ; they are dilated at the base, 

 and clasp around the inner leaves, and their margin is 

 membranaceous. The upper part of the leaf is nearly 

 round, and formed of four hollow tubes, separated from 

 each other by the transverse partitions, which give to the 

 plant its jointed appearance. They taper at the upper 

 part into a sharp point. It is within these broad bases 

 of the leaves, that the fructification lies concealed. The 

 capsules are round and hard. Some of them contain 

 roundish bodies or seeds, which finally open into three 

 triangular valves. The other set of capsules contains 

 extremely minute poUen-like grains, which, however, 

 have, though so much smaller, the same form and 

 character as the larger seeds. 



There are two forms of this Quillwort found in our 

 waters ; one having leaves slender, erect, and densely 

 tufted, the other having them thicker, shorter, and 

 more spreading: but whether these are distinct spe- 

 cies, or whether their variation is referable to some 

 accidental circumstance in the conditions of their growth, 

 seems uncertain. 



The Quillwort cannot always be easily gathered by 

 botanists, though in some ponds fish root it up, and 

 leave portions of it at the edge of the water. They are 



