228 HISTORY OF BRITISH FERNS. 



at first ovate and apiculate, subsequently becoming elliptical ; 

 when young sessile in the sheath, but afterwards acquiring 

 a short footstalk. They are dark-coloured, consisting of 

 about forty to fifty scales, and abounding in light-coloured 

 powdery spores. Each of the scales is impressed with two 

 or three vertical lines. 



This plant is found naturally growing in boggy shady 

 places, and is much more abundant northwards than south- 

 wards, where it is rarely met with. Though distributed 

 sparingly over the United Kingdom, its occurrence is strictly 

 local. 



The stems of this Equisetum are now and have been long 

 employed in the arts as a material for polishing, the im- 

 ported stems being known under the names of Dutch Eush 

 and Shave-grass. They are obtained from Holland, where 

 this species is planted to support the embankments, which 

 it does by means of its branching underground stems. It 

 has been suggested that our own sandy sea-coasts might be 

 profitably planted with it. 



The property which gains for it its commercial value is 

 due to the presence of a very hard coating of silex, which is 

 deposited in the form of little crystals, rendering the surface 

 rough like a rasp or file, and hence not only woods, but 



