FERNS or GREAT BRITAIN. 163 



Horse-tail is marked with distinct ribs, but they are not 

 so raised as to render it harsh to the touch, and their 

 flinty coat is thinner, and formed of more delicate par- 

 ticles than that of some other species. Some of the 

 stems are quite without branches; others have, about 

 the middle, irregular whorls of branches ; sometimes 

 there is about half a whorl here and there; in other 

 cases there is a single branch ; so that the plant exhibits 

 the most irregular and scattered mode of branching; 

 but the branches are never long and spreading like 

 those of the Corn Horse-tail, nor are they ever rough. 

 The presence of the catkin on the fertile stem forms the 

 only dijfference between it and the barren one. This is 

 terminal on the main stem, or more frequently on some 

 of the uppermost branches, and it is bluntly egg-shaped. 

 The scales, which are more than a hundred in number, 

 are black, and the capsules are pale coloured. The 

 numerously toothed sheaths are very short. 



This plant is so much less flinty in its nature than 

 either of the other species, that it is better fitted for fod- 

 der for cattle in this country, though it does not seem to 

 be relished by them while in a green state ; but Linnaeus 

 says, that in Sweden it is cut up for their food, and that 

 the rein-deer feed on it when dried, though they wiU not 

 eat common hay. Mr. Knapp, who, in his "Journal of 

 a Naturalist," remarks that it is a favourite food of the 

 common water-rat, adds : " A large stagnant piece of 

 water in an inland county, with which I was intimately 

 acquainted, and which I very frequently visited for many 

 years of my life, was one summer suddenly infested with 

 an astonishing number of the short-tailed water-rat, none 



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