BRITISH FERNS. 
The section of the stem differs from that of E.hyermle, to 
-which it presents a general resemblance, in being smaller, 
showing fewer ridges, and having the cavities placed rather 
nearer the inner margin; the central cavity is also pro¬ 
portionally smaller. It has, consequently, on the extenor, a 
series of ridges formed of twin projections representing the 
double row of silicious.particles which extends along each 
This plant 
i moist hanks of thp 
.tain glens of Scotland and the n 
This plant is the Equisetum hyemale of botanists. The 
♦terns are of a deep glaucous green, and all alike in structure, 
{hose which bear fructification differing in no other particular 
from those which do not They grow upright, from two to 
three feet high, and are scarcely ever branched: wheu this 
does occur a solitary branch is produced, and this protrudes 
from below the base of one of the sheaths of the stem; they 
are cylindrical, tapering off at the apex, and marked on the 
thicker parts with from fourteen to twenty ridges, formed of a 
doable row of elevated points, consisting of crystallized sm- 
cious particles; hence the stems are very rough. In this 
* species the sheaths fit closely around the stems, so that they 
are nearly cylindrical; they are marked by the same number 
of ridges as the stem, but they are less prominent, and ter¬ 
minate in a series of black, membranous, bristle-shaped 
teeth, which soon fall off, and leave the margin crenated. 
^Theaheaths t 
from this they change to be entirely black; and finally they , 
become whitish in the middle, leaving a narrow ring of black 
ion of the stem, shows on the extern* 
a series of "distinct ridges, formed of twin projections, and ■ 
-varying in number, as has been already explained; opposite 
to the farrows, between them, and occupying about the cen tre 
, of the solid cylinder, is a ring of moderate-sized cavities. . 
The central cavity is comparatively large*. _ . 
This plant grows naturally 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 Equisetuni are employed in the arts as a 
material for polishing, and are imported under the names ox - 
