250 BOTANY. 



the filaments in the one case (Butbochcete) being branched and terminated 

 with setae, while in the other case (CEdogonium and its allies) the fila- 

 ments are not branched, and are destitute of true setae. 



(b) The old genus CEdogonium is divided by Wood into three new- 

 genera, as follows : 



Monoecious: antheridia and oogonia upon the same individual 



CEdogonium. 

 Dioecious : antheridia and oogonia arising upon distinct individuals 



Pringsheimm. 

 Gynandrous : antheridia upon dwarf plants, growing attached to 



the female plant Androgynia. 



Wolle records thirteen species of the first, thirteen of the second, 

 and twenty-six of the third of the foregoing divisions in the United 

 States. He does not, however, consider these divisions as having 

 generic rank. ("Fresh-water Algae of the United States," Vol. I. 

 p. 66.) 



(c) The genus BulbocTimte includes gynandrous species, of which 

 there are sixteen in the United States. 



III. CLASS COELOBLASTE^E. 



333. In the plants of this class the protoplasm is con- 

 tinuous throughout the vegetative organs of the plant, and 

 is not divided into cells. Only the reproductive organs are 

 separated by partitions. They may hence be spoken of as 

 unicellular, although they often attain a considerable length 

 and are frequently much branched. 



The other characters of the group will be best understood 

 from a study of some of the plants included in it. Many of 

 them are chlorophyll-bearing plants, living in brooks and 

 streams, while others are destitute of chlorophyll, and are 

 saprophytes, living upon decaying animal or vegetable matter, 

 or are parasites, living upon the living tissues of the higher 

 plants. 



334. The genus Vaucheria may be taken as a represen- 

 tative of the chlorophyll-bearing members of this class. It 

 is a filamentous alga growing in water or on damp earth, and 

 forming dark green tufts. Each plant consists of long, 

 branching, thick-walled tubes, which have a rather large 

 diameter ; they are attached to the earth, or to sticks or 



