EQUISETUM, 
277 
Equisetum variegatum, Weber and Mohr. 
The Variegated Hough Horsetail. 
This species is found on the banks of rivers and lakes, 
and in sandy places near the sea. There is considerable 
variation among the plants classed under this name, and 
met with in these different localities, the differences ap- 
pearing to be permanent under cultivation, but we have 
not yet sufficient evidence to treat them as distinct species. 
We therefore include as varieties or forms of mriegatum^ 
the dwarf procumbent plant sometimes called E. arena- 
rium, and the tall stout erect form which has been named 
E. WilsonL 
This is one of the species whose stems are all similar, 
and almost quite unbranched. It extends by means of a 
widely-creeping underground stem, rooting in whorls like 
the other species, and producing numerous aboveground 
stems, often springing from joints in such close proximity, 
that they appear in dense tufts. Though so numerously 
branched just beneath or at the surface of the soil, it is 
not usual that any branches are produced on the exposed 
part of the stems ; but this sometimes does occur, such 
