282 BOTANICAL GAZETTE [APRIL 
time than the deciduous tree. Because of the equable distribution 
of moisture throughout the year in sufficient quantity in the eastern 
United States both can exist, although the deciduous element is able 
to occupy the mesophytic areas almost to exclusion of the coniferous 
element. In the northwestern United States the conifers, because 
the climate in which they grow is more suited to them, are able to 
occupy the mesophytic areas, and hence, so far as that. climate is 
concerned, are mesophytes. Although they may have xerophytic 
leaves, the structure of the tree as a whole is more mesophytic during 
the non-growing season than is that of the deciduous tree. Taking 
the entire year into consideration, for the reasons given above | 
think that I am entirely justified in speaking of conifers as meso- 
phytes. 
III. THE INFLUENCE OF FIRES ON THE PRESENT COMPOSITION OF 
THE FORESTS OF FLATHEAD VALLEY. 
In the discussion of the forest conditions up to this point little 
attention has been given to the influence of fires. There is scarcely 
a section of land in the area investigated that has not been more or 
less burned over. In some places mere surface fires have run through 
the woods, scorching the trunks of the trees sufficiently to scar them. 
In other situations the fires have burned vigorously through small 
areas killing many of the trees. Still other fires have destroyed com- 
pletely large areas, leaving many acres with not a single tree. Such 
is the case on the west slope of the Mission Mountains (figs. 4, 16, i ). 
There are many small clearings made by settlers, who after proving 
up their claims have deserted the cabins erected upon them (fis ‘ 9). 
By marshaling the facts collected by a study of the conditions 
of reforestation in these fire clearings, nearly all stages in the ag e 
lishment of new mature forests were determined. Studies in similar 
regions outside of the area plotted have proved very helpful in the 
interpretation of these conditions. Some important principles must 
be kept in mind in explaining what plants will first get @ foothold in 
the open places made by fires. These are as follows: 
1. The subterranean parts of some plants that are able to sprout 
from roots or underground stems may not be destroyed by ~ 
The sprouts of these species will give the burn a decided aspect 
a short time. 
