THE HOKSETAIL. 49 



The rough-horsetail or Dutch rush (E. hyemdle, 

 Linn.), is scarcely known in the southern and mid- 

 land parts of England, and in Ireland has only, we 

 believe, been found in the counties of Dublin and 

 Wicklow. 



The E. Mackati, Newman ; (E. elongdtum of 

 Hooker) ; was discovered by Mr. Mackay, in the 

 counties of Derry and Antrim, and has since been 

 met with in other localities in the north of Ireland, 

 and, also, as stated by Schkuhr, in Wales. Many 

 able botanists are, however, unable to give their 

 assent to its separation as a distinct species, deem- 

 ing it merely a persistent variety of the E. variegd- 

 tum, a pretty little species, which, unlike most of 

 the family, usually grows in dry and shifting sand 

 in the neighbourhood of the sea-shore, though it is 

 sometimes found, as at Mucruss in Ireland, and in 

 the Dublin canal, in fresh water. It is certainly a 

 rather rare and local plant, and very variable in 

 its form and mode of growth ; though it less rarely 

 becomes branched than does the E. Mackaii. 



To the marsh-horsetail, E. palustre, I have already 

 referred, as a noxious weed in the vicinity of water- 

 courses and drains, where it sometimes becomes 

 almost as formidable an invader as the Anachdris 

 alsindstrum, the intrusion of which into this country 

 has recently excited so great an alarm. Like the 

 last named Equisetum, this species is liable to very 

 considerable aberrations from its normal character. 



The water-horsetail, E.fluvidtile, Linn. (E. limo- 

 sum of Smith, Hooker, and Babington) is a very 

 handsome plant, of frequent occurrence in marshy 



D 



