210 
BRITISH FERNS. 
perceptible roughness. The cone is blunt and elongated, 
and ripens in April. 
A section of the stem reveals a series of slight ridges 
on the external surface, a 
circle of large cavities in the 
centre of the substance of the 
cylinder, and also a circle of 
smaller ones near the internal 
surface. 
This is the most elegant of 
our native Horsetails ; its 
long drooping branches re- 
mind one of the form of some 
tropical cypress, and present 
a charming object in the sub- 
alpine thickets which it fa- 
vours by its presence. It is 
very local, but abundant where 
it once settles. 
It is common in the United States, Canada, and 
throughout temperate Europe. 
62. Equisetum limosum, Linn. Smooth Naked 
Horsetail. 
Caudex creeping, jointed, dark-coloured. Loots in whorls. 
Stems ribbed, smooth, generally simple, barren and fertile stems 
alike. 
The Smooth Naked Horsetail puts up stems which 
are generally simple, but sometimes slightly branched. 
There are from ten to sixteen blunt ridges and sheaths, 
cut into the same number of dark-coloured awl-shaped 
teeth. The cones are oval, generally sessile, the scales 
