10 



PLANT BIOLOGY 



With reference to altitude, societies might be classified 

 as lowland (which are chiefly wet-region), intermediate 

 (chiefly mid-region), subalpine or mid-mountain (which are 

 chiefly boreal), alpine or high-mountain. 



The above classifications have reference chiefly to great 

 geographical floras or societies. But there are societies 

 within societies. There are small societies coming within 

 the experience of every person who has ever seen plants 



Fig. 8. — A Wet-region Society. 



growing in natural conditions. There are roadside, fence- 

 row, lawn, thicket, pasture, dune, woods, cliff, barn-yard 

 societies. Every different place has its characteristic vegeta- 

 tion. Note the smaller societies in Figs. 8 and 9. In the 

 former is a water-lily society and a cat-tail society. In 

 the latter there are grass and bush and woods societies. 



Some Details of Plant Societies. — Societies may be com- 

 posed of scattered and intermingled plants, or of dense 

 clumps or groups of plants. Dense clumps or groups are 

 usually made up of one kind of plant, and they are then 



