GLYCERIA FESTUCEFORMIS IN IRELAND ‘79 
of the Mediterranean ; _ with the failure of this key-stone of the 
arch, where is our hyp 
But de espite this ae let us, ‘in the roi of science,” 
say, Northern Italy, where the plant does grow, had at some time 
been imported, it surely ci ca a very elastic imagination to con- 
ceive how the seed ofa plant which affects such a habitat as Glyceria 
festuceformis is likely to become mixed with cereals. The bulk 
of distillery and corn-mill aliens are weeds of cultivated * waste 
ground—Melilots, Medicks, Sisymbriums, Silenes, and a hundred 
more—and plants of other situations, such as seashores, or marshes, 
or woods, are generally conspicuous only by their absence. An 
a of the Comber casuals shows that they are no exception 
to this 
Would: it be rational to doubt that Sci) ‘pus triqueter is come y on 
the Shannon estuary because it could be shown that of the 
Limerick flour-mills had, at some time or other, used iia that 
came from the South of England? Yet the Limerick casuals are 
legion, several of them have established themselves, and S. trigqueter 
grows Meas a stone-throw of some of these. 
Then, further. Having, by some strange chance, got the seeds 
of our ee ee grass (they are not particularly light se eeds, nor 
gifted with any sate means of dispersal) mixed with our foreign 
grain, and that grain duly transported to Comber, and the seeds 
safely launched as into the river, how comes it that, though 
capable even as a recent i a) igrant of forming an extensive colony 
across eight miles of sea—a remarkable feat—the plant has not 
established itself by the Danie River, where the ground is ae 
suitable, and where there must have been a saneee seeds cooing 
= one which reached its distant actual station? Yet G. fest 
rmis has never been detected on e well- Stal ground. Could 
if even be shown that any one of the Comber aliens has spread 
down the river and established itself, this at least would be a straw 
to which we might cling. But even this collateral evidence is not - 
forthcoming. I need not pursue the matter further. Of course it 
may be argued that plants do spread to unexpected places, and that 
we cannot prophesy the range oe of an ave: from the known 
facts of its introduction. Quite But in the present case, jthe 
fraction representing the probability of ae "ep in the hypothesis 
is so small, that the product is a fraction which is for practical 
purposes insignifican 
nly in our distilleries and flour-mills, but in stores, and 
indeed i in every grocer’s s shop and hen-run over the country, foreign 
grain is to be found. It is little exaggeration to say that seeds of 
foreign plants rain down year by year all over our islands, and this 
it is that makes the work of the field botanist nowadays so difficult ; 
but, unless built on some foundation of fact, and supported by 
buttresses of probability, an ao raised on this picnuiianbaues 
Could n Lett—who, by the way, does 
not say that he has studied either the plant, or its Irish habitat, or 
