118 PRACTICAL BOTANY. 



CLASS III. The Red Algae (Rhodophycece or Floridece). 

 These are for the most part the Red Seaweeds. A few 

 live in fresh water. They are chlorophyl-bearing, but the 

 green is obscured by the presence of a red coloring matter, 

 phycoerythrin. In some instances the color is brown, 

 yellow, dull white, or even green. The Red Algae are 

 distinguished from the Brown and Green Alga3 by the 

 higher development of the sexual reproductive organs. 

 The higher differentiation and development of the vegeta- 

 tive organs also place these plants above all other Algse 

 in the classification. 



The reproductive processes in the Red Algse resemble 

 very much those already described for the Coleochgetese, 

 though they are in general of a higher order of develop- 

 ment. There are, of course, variations in the different 

 species. The asexual reproduction is by the formation of 

 nonmotile tetraspores in the terminal cells of branches or 

 in any of the cells of special branches. The sexual repro- 

 duction, which has been less frequently observed, does 

 not usually occur on plants that reproduce themselves 

 asexually, though in some instances both modes of repro- 

 duction have been known to occur in the same individuals. 

 The alternation of generations is well marked in many 

 plants ; the ordinary form is the gametophyte. 



The plants may be either monoecious or dioecious. 

 The antheridia may consist of a single cell each, or they 

 may consist of a number of cells. The antheridia do not pro- 

 duce true antherozoids, but rather naked masses of proto- 

 plasm without cilia or other means of locomotion. They 

 are transported by currents in the water and, as there is 

 reason to believe, by fish which feed on seaweeds, until 

 they come in contact with the female organ of reproduc- 

 tion, the procarp, which in many respects resembles the 

 pistils of the Flowering Plants. The result of the fer- 

 tilization of the procarp is a carpospore, but the variations 



