CHAPTER XII 
HYDROPHYTE SOCIETIES 
130. General character. Hydrophytes are related to 
abundant water, either throughout their whole structure 
or in part of their structure. It is a well-known fact that 
hydrophytes are among the most cosmopolitan of plants, 
and hydrophyte societies in one part of the world look 
very much like hydrophyte societies in any other region. 
It is probable that the abundant water makes the condi- 
tions more uniform. 
It is evident that for those plants, or plant parts, which 
are submerged, the water affects the heat factor by dimin- 
ishing the extremes. It also affects the light factor, in so 
far as the light must pass through the water to reach the 
chlorophyll-containing parts, as light is diminished in 
intensity by passing through the water. Before consider- 
ing a few hydrophyte societies, it is necessary to note the 
prominent hydrophyte adaptations. 
131. Adaptations. In order that the illustration may be 
as simple as possible, a complex plant completely exposed 
to water is selected, for it is evident that the relations of a 
swamp plant, with its roots in water and its stem and leaves 
exposed to air, are complicated. A number of adaptations 
may be noted in connection with the submerged or floating 
plant. 
(1) Thin-walled epidermis. In the case of the soil-re- 
lated plants, the water supply comes mainly from the soil, 
and the root system is constructed to absorb it. In the 
case of the water plant under consideration, however, the 
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