56 THE NATURAL HISTORY OF BRITISH GRASSES. 
and its habits point it out as well adapted for glades in 
parks, and under trees. Its herbage, though not of great 
amount, is of good quality, and we have observed that cattle 
eat it greedily. 
6. Poa fluitans—floating meadow-grass. In this species 
we have a form at first sight so distinct from Poa as almost 
to entitle it to another generic name, which indeed by some 
botanists has been given, in that of Gilyceria, a separation 
which we should at once adopt, both from its structure and 
habit, were this the only species in the group; but its con- 
geners, P. maritima, P. distans, P. procumbens, sufficiently 
unite it to the true Poas for all practical purposes. This 
grass, with its evergreen leaves, will be constantly found 
floating on the water of the pool or the stream; in the 
summer it sends up some upright culms, which are more or 
less branched, and, with the whole herbage, very sweet in 
flavour, on which account cattle prefer it when young to 
almost any other species; it is, however, remarkably liable 
to become ergotised—a circumstance which would appear to 
render it highly injurious to cattle which are obliged to par- 
take of it, arising either from the ill effects of the ergot 
itself, or the damp circumstances under which the grass 
grows, or perhaps both causes combined. In some cases 
which have come before us, abortion in cows has been fre- 
quent in low meadows traversed by watercourses and wet 
stretches in which this grass has been abundant. 
‘We may here refer to another species in the Poa (Glyceria) 
aquatica, which is a constant denizen of rivers, ditches, and 
watercourses, where it frequently grows in thick masses of 
large upright leaves and culms, while its creeping rhizome 
assists in keeping up the mud and dirt, so that this plant 
often becomes a serious obstruction in watercourses, in flat 
countries especially, vitiating a whole system of draining 
from keeping up the water. From such positions it should 
be removed with as great care as weeds from a crop, and 
indeed it may here not be out of place to state that several 
species, not only of grasses but other plants, act prejudically 
