248 HISTORY OF BRITISH FERNS. 



The name Equisetum is compounded from equus, a 

 horse, and seta,, a hair or bristle ; whence comes the 

 English name of Horsettiil, — a not inapt comparison with 

 the barren stems of some of the species. 



Equisettim Telmateia, Ehrhart. 



The Great Horsetail ; or Great Water Horsetail. 

 (Plate XX. fig. 2.) 



This is one of those species in which the ordinary fertile 

 and the barren stems are perfectly dissimilar, the former 

 being short and quite simple, the latter tall and compoundly 

 branched. Occasionally a third sort of stem a kind of 

 compromise between the two, is produced late in the season, 

 reaching maturity about August, and bearing a very small 

 proportion to tlie exclusively barren or fertile stems. They 

 are smaller, though with longer joints ; have shorter, less 

 spreading sheaths ; and bear catkins which are smaller than 

 usual. This state of the plant has been attributed to 

 drought ; and seems to be one of those occasional and in- 

 constant variations to which plants are liable, as they are 

 influenced by the external circumstances of soil or climate, 

 or the peculiarities of the seasons. 



The barren stems of this species are very stately objects 



