THE BRITISH HORSETAILS. 107 



forms, connected together like the jewels of a necklace by a 

 chain of particles forming a sort of curvilinear quadrangle ; 

 these rows of oval combinations being arranged in pairs. 

 Many of the particles which form these straight lines do not 

 exceed the five-hundredth part of an inch in diameter. 



Beyond their employment in the arts, the Eqiiisetums are 

 of litle importance in an economical point of view. They 

 are useless as fodder, and exploded as physic, though they 

 have had some reputed astringent virtues. The under- 

 ground stems, however, contain in winter, when the plants 

 are inactive, a considerable quantity of starch, and they may 

 be occasionally eaten by animals. 



The jointed tubular silicious stems, and terminal cones 

 of fructification, are marks by which the Equisetums may 

 always be readily distinguished from all other plants ; but 

 the species are not so easily recognised among themselves, 

 owing to the great sameness which occurs among certain 

 groups of them. The chief features relied on for their dis- 

 crimination, are the similarity or otherwise of the fertile and 

 barren stems, the number of ridges or striae which occur on 

 the exterior surface of these stems, and the structure of the 

 sheaths which surround the joints. By means of the pecu- 

 liarities which these parts present, the species may be cer- 

 tainly identified, and after a little experience has been had, 

 several of them may be at once known by means of those 

 first-sight appearances which become associated with the 

 plants in the mind of the attentive student. 



The name Equisetum is compounded from eqtius, a horse, 

 and seta, a hair or bristle ; whence comes the English name 

 of Horsetail, a not inapt comparison with the barren stems 

 of some of the species. 



THE GREAT HORSETAIL; OR, GREAT WATER HORSETAIL. 



This plant, the Equisetum Telmateia of botanists, and 

 called also the Great Mud Horsetail, is one of those species 

 in which the ordinary fertile and the barren stems are per- 

 fectly dissimilar ; the former being short and quite simple, 

 the latter tall and compoundly branched. Occasionally a 

 third sort of stem intermediate between the two, is produced 

 late in the season. 



The barren stems are very stately objects when in a luxu- 

 riant condition of growth. They grow erect, from six to 

 seven feet or more in height, and are clothed nearly to the 

 bottom with spreading proximate whorls consisting of from 

 thirty to forty branches, which are sometimes again 



