DEVELOPMENT OF PLANTS 



199 



usually formed in pairs in small cells and are similar to but 

 smaller than the zoospores, while the female gametes are de- 

 veloped singly in the ordinary cells of a filament which become 

 greatly enlarged and spherical or void in form (Fig. 116, A, B). 

 The female gamete is motionless but the colorless region on one 

 side of the gamete certainly suggests the idea that this body is 



FIG. 117. FIG. 1 1 8. 



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

 growths of the cells. 



FIG. 1 1 8. 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. 



related to the zoospores and male gametes, but that it has lost 

 its cilia. At maturity, openings of various kinds appear in the 

 oogonium through which the male gametes enter and one fuses 

 with the female (Fig. 116, A, o). The thick-walled gametospore 

 that results from this union is set free by the decay of the oogonial 

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



