EXERCISE 118 



COMPETITION BETWEEN PLANTS 

 Materials. A patch of weeds in early spring. 



Directions for work. 1. Locate a place where the weeds are 

 coming up thickly. Mark off a space about a foot square. 

 Count the number of weed seedlings. If there are any remains 

 of last year's weeds, estimate the number of weeds that were 

 able to reach maturity on the same area last year. How do the 

 two numbers compare ? If possible, follow the area during the 

 season and learn just what becomes of the plants you find there 

 now. 



2. Allow the weeds to grow undisturbed along with the crop 

 in a small part of a garden. What is the effect on the crop in 

 comparison with the similar crop in parts of the garden that are 

 cultivated? Can you discover by what means the weeds harm 

 the crop in this particular instance ? 



References 



BERGEN and CALDWELL. Practical Botany, chap. xxv. 

 BERGEN and CALDWELL. Introduction to Botany, chap. xx. 

 BERGEN and DAVIS. Principles of Botany, pp. 447-453. Ginn and 



Company. 



CALDWELL and EIKENBERRY. Elements of General Science, Rev. Ed., 

 chap, xxxii. Ginn and Company. 



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