Horsetails 



of Dutch Rush. It grows very abundantly on the 

 canal embankments and sea-dykes in Holland, where its 

 vigorous underground root system proves invaluable in 

 binding together the loose soil. As already pointed 

 out, this is the species most largely employed as 

 a polishing medium. In Britain it is not too well 

 distributed and may be regarded as rather rare. The 

 barren and the fertile stems are both tall and much 

 alike in appearance. The great abundance of flinty 

 particles the stems contain renders the plant exceedingly 

 rough to the touch. It is this roughness which makes 

 it so valuable from the commercial point of view. The 

 sheaths, too, are very distinctive. They are whitish, 

 with black bases and margins. 



Like Equisetum limosum, this horsetail has naked 

 stems, which are rarely, if ever, branched. When 

 branches do occur, they are confined to the base. The 

 botanical name of this species is Equisetum hyemale. 

 Hyemale is a Latin adjective signifying " pertaining to 

 winter," an allusion to this plant persisting during that 

 season. 



The chief points in this chapter, apart from the 

 descriptions of individual plants, are as follows : 



1. Horsetails are classed as fern allies, because, like 

 ferns, they are reproduced from spores with the inter- 

 vention of a prothallium existence. 



2. While there is no differentiation in the spores of 

 horsetails, they nevertheless give rise to prothallia of 

 two kinds, male and female. To the spores are 



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