i88 



HIGHER TYPES OF REPRODUCTION 



walls and germinates after a resting period very much as in the 

 case of Ulothrix. The contents of the gametospore is extruded 

 through the ruptured wall as a delicate sac and then divides, 

 forming four zoospores which produce new plants (Fig. Ii6, C-G). 

 The question will naturally arise as to the force that brings these 

 and other gametes together. The frequently observed aggrega- 

 tion or swarming of the male gametes about the females renders 



Fig. 117. 



Fig. 118. 



Fig. 117. Coleochaete, showing the radiating filaments and hair-like out- 

 growths of the cells. 



Fig. 118. Sexual reproduction of Coleochaete: A, end of a filament bearing 

 the male, an, and female, og, reproductive organs. B, the gametospore is 

 being enveloped by the adjacent filaments of the plant. C, gametospore 

 germinating. Eight cells have been formed, rupturing the walls of the gameto- 

 spore. — After Oltmann. 



probable the view that some substances as organic acids, etc., are 

 developed in the gametes that serve to draw them together when- 

 ever they come within a certain distance of each other. 



The consideration of Coleochaete, a plant of the same order as 



