174 



BOTANY 



and brown seaweeds the chlorophyll is concealed by other coloring 

 material in the plant body. In the olive-brown fucus (the com- 

 mon rockweed) it is easy to prove the presence of chlorophyll by 

 cutting open the bladders which are found in the plant body. 

 Chlorophyll may also be extracted by placing the plant in alcohol. 

 The red seaweeds are among the most beautiful and delicate of 



Rockweed, a brown alga, showing the distribution on rocks below highwater mark. 



all plants. They may be mounted under water upon cardboard 

 and then studied after dryang.^ 



Green Algae. — The collection of plants known as the green 

 algae are of more interest to us because of their distribution in 

 the fresh waters of New York state, and also because of their 

 economic importance as a supply of oxygen for fish and other ani- 

 mals in the waters of our inland lakes and rivers. Our atten- 

 tion is called to them in an unpleasant way at times, when, after 

 multiplying very rapidly during the hot summer, they die rapidly 



* For the study of a seaweed, see Hunter and Valentine, Manual, pa^c 81. For 

 reference reading, see Bergen and Davis, Principles of Bolany, page 172 



