at first ovate and apicnlate, 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 southwards,
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 imported
stems being known under the names of Dutch Kush
and Shave-grass. They are obtained from Holland, where
this species is planted to support the embankments, which
it does by means of its brandling 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 sdex, which is
deposited in the form of little crystals, rendering the surface
rough like a rasp or file, and hence not only woods, but
metals and stones may be polished by it. This siliceous
coating is so entire, and of such density, that it is stated the
whole of the vegetable matter may be removed by maceration,
or, according to others, by burning, without destroying
the form of the plant. The minute crystals of silex, of
which the flinty coating consists, are arranged with a degree
of regularity which, under a microscope, has a very beautiful
appearance; they form a series of longitudinal elevated
points, and in the furrows between them are cup-shaped
depressions, at the bottom of each of which is placed a
stomate or pore.
All the species of Equisetum have a flinty coating to their
stems, and may be, and are, more or less employed in polishing
; but the stems of the E. hyemale are much preferable
to those of the other kinds, in consequence of their rougher
and more hardened surface.
E q u ise t um l im o sum , Linnceus.—The Water Horsetail,
or Smooth Naked Horsetail.
This is a common species and generally distributed,
occurring principally in pools, ditches, and marshy places,
though occasionally in running streams. It is rather a
tall-growing plant, the stems rising from two to three feet
or more in height, springing from the joints of the dark