each furrounded with a fhort lax vagina, black at the bafe and margin,
but of a pale green in the middle.
The fpaces between the joints are of a ftrong bluiih green, channelled
with twelve or fixteen furrows, and having alternate ridges, which are
armed with hard, ihort, rough fpines, regularly placed in one line, along
each ridge, as is exprcfled at b ; where a vagina, a, and part of the ftem
are magnified.
The ftem, as in the other fpecies, confifts o f a number of fiftular
tubes, ivhich are bound together by an external and internal bark, and
form one general fiftular tube. In this fpecies the inner bark is fmooth
and white.
The barren leaves in this fpecies are not to be diftinguiihed from the
fertile in any thing, but the want of frudification, and in their upper
extremities terminating in a fine point.
Both the one and the other are moft commonly fimple, but fometimes
emit one or two branches from the lower joints, as is expreifed in the
plate. Thefe are o f the fame figure and ftrudure as the primary leaves,
only fmaller, and confifting o f fewer joints.
This fpecies is diftinguiihed by the ihort obtufe dents of the vaginæ,
by the remotenefs of the joints, by the roughnefs of the touch, and by
being an evergreen.
The only places where I have feen it grow, are amongft the buihes
clofe by the brook at the lower end o f the Helk, near Ingleton ; and in
a field, belonging to an eftate called Upper B rie r, in Northowram, near
Halifax.
P I L U L A R I A .