Suggestions for Laboratory and Field Work to Precede 

 Chapter Eighteen 



1. Make a field study of Protococcus to determine (i) where it 

 grows, (2) its relation to light, moisture, gravity, and roughness 

 of the substratum, and (3) how it is disseminated. 



2. Make a field study of pond scums in a pond or small stream. 

 In a jar, collect material for laboratory study ; cover the bottom 

 of the jar with mud from the bottom of a pond or stream. The 

 amount of algae should be very small compared with the volume of 

 water. If these algae are collected in late autumn, they may be 

 grown in winter at a north window. 



3. The forms of the cells and the methods of reproduction may 

 be studied from fresh or preserved material. Particular attention 

 should be given to the differences between vegetative multiplica- 

 tion, sexual reproduction, and asexual reproduction. 



4. Dried specimens of Fucus, Laminaria, Sargassum, Poly- 

 siphonia, and Dasya will give an idea of the Brown and Red Algae. 



5. In early spring place some algae in an aquarium with snails 

 and young tadpoles. Note the rate at which the algae disappear. 

 If you can find frog or toad eggs, the experiment may be started 

 with them. The water should be changed occasionally. 



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