THE ORGANIZATION OF PLANTS INTO SOCIETIES 57 
new places for growth, adapt themselves to new conditions, 
or die. Consequently it can not always be said that plants 
growing in certain regions are there because it is their best 
home. They frequently grow where they are because they 
must remain there or die. In the struggle for existence 
some plants are frequently forced from their most favorable 
growing places into less desirable ones. 
Plants to grow in a given region must have structures 
somewhat adapted to the peculiarities of that region. For 
example, we should not expect the water-lily to grow well in 
the soil on a windy mountain slope. Although there may 
be many species growing in a given region, they must have 
some adaptations in common to enable them to live in the 
same society. 
Work on a few plant societies will be suggested, and this 
may be extended profitably wherever time and available re- 
gions for considerable field-work make such possible. 
LESSON XXX 
A hydrophyte society 
Materials.—Select a region where plenty of water or 
marsh plants are growing. A pond, lake, or river bayou 
will usually furnish a fairly good region. 
Observation and study.—Make a list of the kinds of 
plants found in the water, and note the position of each.t 
Observe the following points: 
Whether plants are submerged, floating, or rise into 
the air. 
The number, size, and form of leaves. Do you find any 
plants with two kinds of leaves, one submerged, the other 
exposed ? 
Compare submerged leaves in general with those ex- 
1 The teacher should furnish names of the plants, or, if means of 
identification are present, the students may identify them. 
