CHLOROPHYLL; STARCH. 69 



stronger than necessary, and the chlorophyll bodies move so that their edges 

 are exposed to the incidence of the rays. This movement of the chlorophyll 

 bodies is different from that which takes place in some water plants like 



Fig. 56. Fig. 57. 



Ceil exposed to weak diffused light show- Same cell exposed to strong light, showing 



ing chlorophyll bodies along the horizontal chlorophyll bodies have moved to perpen- 

 walls. dicular walls. 



Figs. 56, 57. Cell of prothallium of fern. 



elodea. The chlorophyll bodies in elodea are free in the protoplasm. The 

 protoplasm in the cells of elodea streams around the inside of the cell wall 

 much as it does in nitella and the chlorophyll bodies are carried along in the 

 currents, while in nitella they are stationary. 



