IV % ON PLANT LIFE 149 
In illustration of the first case I may refer 
to many alpine plants, the well-known Edel- 
weiss, for instance, where the woolly covering 
of hairs prevents the “ stomata,’ or minute 
pores leading into the interior of the leaf, 
from being clogged up by rain, dew, or fog, 
and thus enable them to fulfil their functions 
as soon as the sun comes out. 
As regards the second case many desert and 
steppe-plants are covered with felty hairs, 
which serve to prevent too rapid evaporation | 
and consequent loss of moisture. 
The woolly hairy leaves of the Mulleins 
(Verbascum) doubtless tend to protect them 
from being eaten, as also do the spines of 
Thistles, and those of Hollies, which, be it 
remarked, gradually disappear on the upper 
leaves which browsing quadrupeds cannot 
reach. 
I have already alluded to the various ways 
in which flowers are adapted to fertilisation 
by imsects. But Ants and other small creep- 
ing insects cannot effectually secure this object. 
Hence it is important that they should be ex- 
cluded, and not allowed to carry off the honey, 
