250 BOTANY. 



the filaments in the one case {BuJboclimte) being branched and terminated 

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

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



(5) 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 



— Pringsheimia. 

 Gynandrous : antheridia upon dwarf plants, growing attached to 



the female plant — Androgynia. 



We have no known representatives of the first in the United States ; 

 of the second Wood records one species, P. inequalis, which is closely 

 allied to P. gemelliparum (D, Fig. 167) ; of the third genus we have 

 four species, of which A. midtispora and A. mirdbilis are the most 

 common. 



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

 there are three recorded in the United States ; the most common is B. 

 ignota. 



§ III. Class Cceloblastejb. 



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 



