48 PLANT-LIFE 



one of them enters the oogonium, fuses with the egg-cell, 

 and so fertilizes it. Androspores are usually produced 

 by the same thallus that bears oogonia. 



We see from this brief survey of (Edcgonium that 

 although it is an extremely simple plant as regards its 

 thallus, it is well advanced in respect to sex. And within 

 the ranks of the genus much resourcefulness is displayed. 

 It is important for us to specially note the marked 

 difference between the male spermatozoids and the egg- 

 cells. The egg-cells are passive, relatively large, and 

 well nourished; the spermatozoids are active, small, and 

 furnished with just about enough nutrient stuff to serve 

 their turn. The egg-cell needs much store to nourish that 

 which is to be delivered from the innermost sanctuary 

 of its womb; the spermatozoid requires only sufficient 

 to maintain it during its brief activity — to support it in 

 the sacred mission of bearing an element of Life into the 

 sanctuary, an element that stimulates growth. For 

 (Edcgonium, like all plants and animals, obeys the com- 

 mand, " Be fruitful and multiply, and replenish the 

 earth "; it lives for posterity, and seeks the immortality 

 of its kind. 



The fertilization of (Edcgonium, as we shall see later, 

 is in all essentials the same process as is involved in the 

 highest plants. The likeness of its spermatozoids to 

 zoospores is very suggestive; it seems to indicate that the 

 former have evolved from the latter, that if we wish to 

 discover the origin of the sexual spermatozoid we must 

 look for it in the asexual zoospore. 



But we have another inquiry to make. Embryolo- 

 gists assure us that the fertilized ovum, in its germination 

 and development, tends, at least in part, to epitomize the 



