266 HISTORY OF BFilTISII FERKS. 



not providing during summer a supply of this plant and of 

 the Reindeer Moss, for winter use ; thus making some 

 provision for their herds at a time when the ground is 

 covered with frost-bound snow, so as not to risk the loss of 

 their most valuable or entire possessions. An instance is 

 related by Mr. Knapp, in which a colony of the short-tailed 

 water-rats made this plant their food, and in the evening 

 might be heard champing it at many yards' distance. 



Equisetnm palustre, Linnwiis. 

 The Marsh Horsetail. 



A common species in boggy places, and by the sides of 

 ditches and watercourses. It has a creeping underground 

 stem, which is black and shining, and from the joints of 

 this are produced whorls of slender roots. The part of the 

 stem which rises aboveground is erect, growing from a 

 foot to a foot and a half in height. The presence of fruc- 

 tification alone distinguishes the fertile slems from those 

 which are unfruitful ; both being erect, and bearing whorls 

 of numerous branches. 



The stems are somewhat rough on the surface, but less 

 so than in many of the other kinds. They are marked on 

 the exterior by prominent ribs, with intervening broad 



