Red and Br own Algae 



135 



regularity. These rafts of cells drift about freely in 

 open water, and are often taken in the plancton, though 

 rarely in great abundance. They settle betimes on the 

 leaves of the larger water plants, and may be discovered 

 with a pocket lens by searching the sediment shaken 

 therefrom. 



Fig. 53. Alerismopaedia. 



Red and brown alg^e (RJiodopJiycece and PhceophycecB) 

 ■ — These groups are almost exclusively marine. A few 

 scattering forms that grow in fresh water are shown in 

 figure 54. Lemanea is a torrent -inhabiting form that 

 grows in blackish green tufts of slender filaments, 

 attached to the rocks in deep clear mountain streams 

 where the force of the water is greatest. It is easily 



