(EDOGOA'IUM. 



151 



rell. The sexual organs are differentiaterl among themselves, the antheridium 

 is small, and the oogonium large. The gametes are also differentiated in 

 siie, and (he male gamete is motile, and carries in its body the nucleus 

 which fuses with the nucleus of the egg cell. 



But a more striking advance is the fact that the fertilized egg does not 





Fig 152. 



Fertilized egg of cedogonium after a period of rest escaping from the wall of the oogonium, 

 and di\iding into the four zoospores. (After Juranjd.) 



produce the vegetative thread of cedogonium directly, hut first forms four 

 zoospores, each of which is then capable of developing into the thread. On 

 the other hand we found 

 that in spirogyra the zygo- 

 spore develops directly 

 into the thread form of the 

 plant. 



330. Position of cedo- 

 gonium. — CEdogonium is 

 one of the true thread-like 

 algae, green in color, and 

 the threads are divided 

 into distinct cells. It, 

 along with many relatives, 

 was once placed in the old 



genus conferva. These are all now placed m the group 

 Confen'oiJio:, that is, the cotifcrz'a-Hke als^cc. p- 



321. Relatives of cedogonium. — Many other genera Portion of chajtophora 

 are related to «;dogonium. Some consist of simple showing branchmg. 

 threads, and others of branched threails. An example of the branched 

 forms is fotmd in chcetophora, represented in figures 153, 154. This plaiit 

 grows in quiet pools or in slow-rimning water. It is attached to sticks, rocks, 

 or to larger aquatic plants. Man}' threads spring from the same point of 

 attachment and radiate in all directions. This, together with the branching 

 of the threads, makes a small, compact, greenish, rounded mass, which is 



Fig. 153- 

 Tuft of ch^to- 

 phora, natural 

 size. 



