PLANTS THAT ARE ATHLETES 73 



the game, they lose life. And each act of theirs is 

 to benefit not only themselves but also their chil- 

 dren. In this they are like human parents, who, 

 in order to benefit their children, frequently make 

 great sacrifices, and often even risk their own lives ; 

 in the same way plants take many risks to better 

 the condition of their offspring. 



There are a large number of plants which pos- 

 sess the power of spontaneous motion, very similar 

 to that displayed by the lower forms of animals. 

 A striking example of this is found in one of 

 the Alga?, which has an undulating motion pre- 

 cisely like that of certain lower animals. In some 

 forms of fresh-water Algae, reproduction takes 

 place by the formation of "zoospores" which, though 

 exceedingly small, are covered partly or entirely 

 with tiny cilia or hairs. After these small zoo- 

 spores free themselves from the parent plant, the 

 cilia begin to move very rapidly. In addition to 

 this vibrating of the cilia, the body of the zoospore 

 itself has a rotating movement on its axis, caused by 

 spontaneous contractions; and as a result of these 

 civilised actions the entire plant passes through the 

 water with a motion very similar to that of a fish 

 swimming. This continues for a period of from 

 one to three hours, as if, in a boy-like water- frolic, 

 the youthful plant were making the most of its 



