66 PLANT LIFE ON THE FARM. 
as the Blood Red is very hardy, owing its immunity possi- 
bly to its habit of keeping its leaves close to the ground 
during the winter and spring, and, therefore, less exposed 
to sudden changes of temperature. In any case, its 
leaves are more likely to be protected bya coating of 
snow. ‘The selection, therefore, of the kind of wheat 
best adapted for Scotland, for the eastern or for the 
western counties of England respectively, is a matter of 
great consequence. A variety which succeeds in a warm 
moist climate would be quite unsuitable for a drier one, 
even if the temperature sometimes rose higher. 
In moist air it has lately been shown by M. Vesque 
that the leaves are both thinner and longer than when 
grown in dry air, that the vascular bundles of the stem 
are also thinner, and less perfectly developed than in 
dry air. Thus, the effects of a saturated atmosphere on 
the growth of leaves seem to be very similar to those 
mentioned by Rauwenhof as characteristic of plants 
grown in obscurity. When fully exposed to the light, 
in a dry, hot, stagnant atmosphere, where transpiration 
from the surface of leaves is ample, the leaves become 
thicker, their anatomical structure is altered, and they 
show a tendency to become more hairy. 
It would not be worth while for the agriculturist to 
try and make his plants adapt themselves to different 
conditions as the experimentalists and physiologists do, 
but the indications and facts brought forward by the lat- 
ter may very profitably influence the farmer’s selection 
of the particular varieties best suited, by their conforma- 
tion or structure, to meet the vicissitudes of particular 
localities. 
The Influence of Contact on Leaves.—This may be 
dismissed with a few words only, as it is not, so far as at 
present known, of much practical importance to agricul- 
turists, In addition to the movements immediately con- 
