SECTION XIII. PLANT ASSOCIATIONS 



In a preliminary course in botany very little time is avail- 

 able for the study of ecology. A brief field study will, how- 

 ever, give the student a valuable insight into the social life 

 of plants and their dynamic relation to the environment. The 

 following studies may well be assigned early in the spring term 

 and followed as the season advances : 



1. Nature and composition of plant associations. Make a 

 preliminary study of any area of soil ten or fifteen feet 

 square covered with vegetation, as indicated in the 

 following outline: 



a. Kind and number of species associated together in 



one area. 



(1) Count the number of different kinds of plants 



inhabiting the area under observation. Name 

 as many of the species as possible and determine 

 unknown species by consulting manuals. 



(2) Make the same determination for a similar area 



somewhat removed from the first in the same 

 plant association. Do you find any consider- 

 able variation in the two portions of the same 

 association ? If so, account for the variation in 

 number and kind of species occupying the two 

 areas. 



b. Habitat and habit of associated plants. 



(1) Determine as far as possible the environmental 

 factors which characterize the habitat under 

 observation and their effect on plant growth. 

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