PLANT STUDY 



crease among plants. Most plants produce an enormous 

 number of seeds. Have pupils count the number of grains 

 Seed of wheat produced by a single " stool " ; the 



Increase number of seeds in a single poppy head, and 



from these estimate the number produced by an entire 

 plant. Estimate the possible increase for crop after crop. 

 Beginning with a single seed, how long would it take 

 under perfect conditions for any one of the plants studied 

 to occupy all the land in a single city block? in a square 

 mile? in the state? in the United States? That plants 

 do not increase at any such rate is apparent. Why not? 

 What becomes of the seeds thus produced? In early 

 spring have a careful, persevering pupil measure off a 

 square foot or a square yard of ground and carefully pull 

 up and count all the plants that come up in the space. In 

 the same way measure a similar space and let all grow that 

 will. How many of the plants in this space are able to 

 reach maturity and produce seed? Compare this number 

 with the number that started in the space where they were 

 counted. Plants struggle with other plants for space in 

 which to grow. They also struggle for life against ani- 

 mals, poor soil, climatic conditions, and other obstacles to 

 existence. Why do plants produce such a great number 

 of seeds? 



Secure any thrifty plant, six to ten inches high, and place 



its roots in a bottle of water in the schoolroom. Place a 



bottle of the same size, also filled with 



arts of water, beside it for comparison. Note 



a Plant 



after a day or two that more water has 



gone from the bottle containing the plant than from the 

 other. The plant has used some of this water. Which part 



or THC 



