CHAPTER IX. 



BRANCH III. OOPHTTA. 



THE EQG-SPOBE PLANTS. 



269. The distinguishing feature of the plants belonging 

 to this division is that they develop a large cell (the oogone, 

 or oogonium), differing from those about it in size and 

 general appearance, which contains one or more rounded 

 masses of protoplasm (the germ-cells), which are subse- 

 quently fertilized by the contents of a second kind of spe- 

 cial cell of much smaller size (the antherid, or antheridium). 

 The oogone is the female reproductive organ, and the an- 

 therid the male. The protoplasm of the latter is in some 

 cases transferred by direct contact to the germ-cell; in 

 other cases it first breaks up into motile bodies (the anther- 

 ozoids), which then come to and unite with the germ-cell. 



270. The germ-cell itself is never motile, and in most 

 cases it remains within the parent-plant until long after it 

 is fertilized. The result of fertilization is the production 

 of a resting spore (here called an oospore) which differs 

 from the germ-cell structurally in having a hard and gen- 

 erally colored coating, and physiologically in having the 

 power of germination and growth after a period of rest of 

 greater or less duration. 



271. The plants of this division vary greatly as to the 

 development of the plant-body. In some cases it is a feebly 

 united colony, while in its highest forms it is a well-devel- 

 oped thallus, with even the beginning of a differentiation 

 into Caulome, Phyllome, and Root, Most of them are 



