452 General Botany 



side of the original cell wall, and a few minutes later the swimming 

 spores pass out from the cell cavity and swim away. Sometimes 

 all the cells in a filament produce swimming spores at about the 

 same time, and hundreds of these small green bodies may be 

 found moving about in the water. At the end of from 15 to 30 

 minutes the swimming spores settle down on some object and 

 become attached. By the end of a day the cell formed from 

 each spore has divided and produced the first two cells of a new 

 filament. 



The protoplasm of other cells, of the same or other filaments, 

 continues to divide until 16, 32, 64, or more bodies have been 

 formed. These are called gametes. They are similar to the 

 swimming spores but much smaller, and each possesses two cilia 

 for swimming. Like a swimming spore, each of them leaves the 

 old cell through an opening in the wall. The gametes swim 

 about for some minutes and then unite in pairs. They are 

 attached at first only by the ciliated ends, but later the two 

 gametes fuse. The body thus formed may grow directly into a 

 new filament, or it may produce swimming spores from each of 

 which a new filament is formed. 



(Edogonium. (Edogonium is another filamentous alga that 

 flourishes in ponds and streams. In early life the filaments 

 are attached, but large masses of them will often be found free in 

 ponds and stagnant pools. From the cylindrical vegetative 

 cells, large swimming spores are formed. Gametes also are 

 produced. These are of two distinct forms, male and female. 

 Plants belonging to the (Edogonium group may be used to 

 exemplify reproduction in many other algae, whose gametes are 

 essentially like those of more complex plants. 



At the time of production of the gametes, some of the cells in 

 the filament enlarge, become rounded, and accumulate starch 

 and other food material ; also, a small opening is formed in the 

 cell wall. The content of this cell is the female gamete or egg, 

 which like other eggs has in it a store of food. 



