334 Dr. Suirn's Account of several Plants, 
1. Arra levigata *, 
foliis planis; vaginis levissimis, paniculä coarctatä, petalis aris- 
tatis basi villosis, rachi glabra brevissima. 
Found on the high mountains of Clova in Angusshire, as well 
as at the sea-side near Dundee. In the former situation it 
is viviparous; in the latter not so. This grass appears to have 
been overlooked as a viviparous alpine variety of Aira cespitosa. 
At least, so Linnzus, who received it from Lapland by means of 
some one of his travelling pupils, considered it; and probably 
it is the supposed variety, mentioned on the authority of the Rev. 
Hugh Davies, in the Flora Britannica. Mr. Don, however, justly 
remarks, that it differs from the cespitosa in never being above 
a foot, or foot and half, high, even when cultivated in a rich 
moist soil; as wellas in the great smoothness of the herbage 
when drawn through the hand. For, though the edges of the 
leaves are rough, their sheaths and backs are remarkably 
smooth. My acute correspondent thought he had ascertained a 
further difference, in the absence of the woolliness at the base of 
the flowers. This, however, I find not exactly the case; but the 
remark has led to the detection of a curious specific character in 
those parts. This consists in the extreme shortness, and perfect 
smoothness or nakedness, of the little partial stalk which elevates 
one floret, while the very base of each floret is bearded. In 
A. caspitosa thep artial stalk itself is hairy all over, and of a much 
greater length than in our levigata. Mr. Don informs me that the 
latter flowers a month earlier than cespitosa. The root is fibrous 
and perennial. 
The examination of this grass in its viviparous state, teaches 
us one mode in which that phenomenon takes place, and which 
* Engl. Bot, t. 2102. - i 
is 
