210 THE RED ALGAE 



and the reproduction process can be observed at almost any time. 

 After the plants have been exposed for several hours by the low 

 tide the male and female gametes will often be found forming 

 orange yellow and olive green drops at the mouth of the cavities. 

 In this condition the entire process of fecundation and early stages 

 of germination can be studied by transferring a bit of these two 

 fluids to a drop of sea water on a slide and studying them under a 

 microscope. The differentiation of the gametes of Fucus is an 

 interesting one because it represents the stage where the female 

 gamete has become motionless, but is not retained in the mother 

 cell as in Vaucheria and Oedogonium. 



No resting spores are found among the brown algae. This 

 may be connected with the more uniform conditions that ob- 

 tain in the sea where also they are not exposed to the dangers 

 of desiccation as in fresh water forms. It is noteworthy, that 

 although the reproductive organs are, on the whole, more com- 

 plex, fertilization is of a more primitive character than among 

 many of the green algae, in that the fusion of the gametes is 

 effected outside of the gametangia. 



Class C. Red Algae or Rhodophyceae 

 74. General Features. — The Red Algae are largely marine 

 plants. Unlike the brown algae, they reach their greatest de- 

 velopment and abundance in the warmer waters of the temperate 

 and tropical seas and are usually found attached to various ob- 

 jects below tidal marks. Their red pigments probably adapt 

 them to the feeble illumination of the deep waters in which they 

 generally occur. They range through a great variety of forms, 

 from delicate filaments or flattened ribbon-like bodies to struc- 

 tures with cylindrical axes and leaf-like branches (Fig. 125). 

 The elegant symmetry of their branching together with the deli- 

 cacy of structure and richness of coloration has always attracted 

 attention and made them the most familiar of all the algae. 

 They are popularly though inaccurately known as sea mosses. 



Reproduction of the Red Algae. — ^The reproduction of the 

 Rhodophyceae, particularly the sexual method, presents so many 

 modifications and specializations that only the general features 



