512 ECOLOGICAL CLASSIFICATION OF PLANTS 
formation as to what plants can be successfully grown on a 
given area. ‘There are instances, as in case of some of the wild 
lands of the West, where a study of the socicties of wild plants 
has suggested the kind of crop plants best adapted to the condi- 
tions. It is quite probable that more extended studies in Ecol- 
ogy in connection with soil analyses will reveal such a close 
Fia. 463. — A lake which is being rapidly filled up by the accumulation 
of vegetable matter. Swamp societies consisting of clumps of Rushes, Sedges, 
and Sagittarias are most conspicuous about the water. Further back are 
swamp Grasses grading into mesophytic Grasses, and finally on the ridge, 
as shown by the corn field and trees, a typical mesophytic condition prevails. 
After C. M. King. 
association of plant societies and the chemical and physical 
characteristics of soils that the chemical and physical differ- 
ences of soils on different farms or in different parts of the same 
farm may be quite accurately judged by observing the socicties 
of weeds and other wild plants. In reforesting a given ‘area it 
is very essential to take into consideration the plant societies 
adapted to the region. For example, it would be unwise to plant 
Pines on bare sand dunes, or Maples where Black Oaks, which 
grow in much drier situations than Maples, prevail. 
