AIRA SCABRO-SETACEA.
Bristly-leaved. Hair-grass.
Spec. Char. Leaves short, bristle-like, and rough ; stipulae long) calyx with spines on
the keel.
This Aira which we now describe was pointed out to us growing in pits of water on Forfar-heatb,
by Mr. G. Don, a botanist whose intrinsic merits are too little known, and whose friendship we must
ever esteem. This hair-grass possesses constitutional habits the reverse of the preceding plant, which
fixes its station and thrives in dry and arid places, whereas the A. scabro-setacea grows in little hollows
and low places where water has been lodged, and as the fluid exhales the plant fades, and upon
the waters being dried up the Aira dies away. It is usually the case with plants whose general habits
are to vegetate in dry situations, when they by any casualty become fixed in aquatic places, that they
lose a considerable portion o f the harshness they may possess, and become meliorated by the influence
o f the water j but, on the contrary, this plant in moisture (which is essential to its existence) preserves
a rigidity unknown to A . flexuosa in drowth.—— Panicle branches weak and flexile, and we
generally observed three to issue from the lower stage. Leaves rather short, setaceous, and rough,
scaly and membranaceous at their base; sheathing smooth, all the leaves, radical and cauline, furnished
with stipulae; both valves of the calyx with spines.----------The unnecessary creation of species
from trivial variations cannot be too much discountenanced, as pernicious in its consequence, and false
to the true principles of science, but we trust that the plant before us is something more than a casual
deviation, possessing permanent characteristics to entitle it to specific distinction.
A, the valves of the Calyx.
B, the upper Floret, with its hairy peduncle.
C, a radical Leaf, rough, and setaceous.