246 BATTLES OF PLANTS IN THE WORLD 
— 
of a tree to see which one shall get most of the light 
and thus outlive its competitors. 
Certain soils are congenial to certain plants. If all 
plants could grow in all situations, we should have 
fewer kinds of plants because there would be so many 
competitors for every foot of ground. But some plants 
have found one kind of soil congenial to them, and 
other plants prefer another kind of soil. So, many 
plants leave certain territory undisputed, and only 
enter into a contest if some favourable changes take 
place in those localities, provided, of course, their seeds 
get im there. We do sometimes find a few plants 
struggling in a very uncongenial soil, but they never 

FIG, 298. Soil congenial to butterbur and kingcups. 
become real competitors with the plants which like to 
grow there. They are struggling only with the physical 
forces of nature, not with other plants. 
