402 LABRADOR 
piration, but directly increases the tendency to low, shrubby 
growth, and favours anemophilous adaptations (v.e. those 
using the agency of the wind) for pollination and for dis- 
semination of fruits. Differences in the nature of the soil in 
Labrador would seem to be not great, and to derive their 
importance mainly from their ability to conserve moisture, 
free from admixture with growth-hindering acids and salts. 
There are, however, some further direct and important 
influences. One of them, not often mentioned but very 
evident, is the scarcity of insects that aid in pollination. 
The proportion of flowers that are anemophilous, or wind 
fertilized, as compared with those that solicit insect aid, 
is considerable, as might be anticipated from the fact that 
flower-haunting insects are rare. Yet there are many 
flowers of the latter type, though mainly of species that do 
not absolutely depend upon insects for the fertility of their 
seeds. 
Another positive influence is the relatively protracted 
illumination during the period of growth. This, like many 
other influences operative here, has been shown to have a 
tendency to diminish herbaceous growth, affecting the size 
both of the plant and of its leaves; and to favour repro- 
duction. The devices that protect against too great trans- 
piration often serve at the same time to secure protection 
against excessive and prolonged illumination. 
Finally, the shortness of the season of growth is of large 
importance. It is this which forces a large proportion of 
the plants that are to survive under the conditions which 
Labrador supplies, to develop in a previous season the em- 
bryonic preparations for the leaves and flowers that are 
to appear the following summer. Hence is derived the 
