EQUISETUM. 243 



These, on bursting, disperse a great number of greenish-co- 

 loured spores. 



This species grows naturally in moist shady woods ; and 

 though local, owing apparently to the conditions necessary 

 to its growth, namely, shade and moisture combined in a 

 peculiar way, it is, nevertheless, a widely distributed plant, 

 and can hardly be considered as uncommon throughout the 

 United Kingdom. Its fertile stems are in perfection about 

 the middle of April, and its barren stems in June. 



EQUISETUM TELMATEIA, Ehrkart. The Great Horsetail, 

 or Great Water Horsetail, of some ; Great Mud Horsetail 

 of others. (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 is produced, 

 late in the season, which may be called a kind of com- 

 promise between the two. Mr. Newman describes such 

 steins as reaching maturity about August, and bearing a 

 very small proportion to the exclusively barren or fertile 

 steins. They are smaller, though with longer joints, have 

 shorter, less spreading sheaths, and bear catkins which 

 f<re smaller than usual. This state of the plant has been 



