120 BOTANY. [chap. iv. 



the fertilized body, on germination, to commence assimi- 

 lating food for itself from the very first, even before a 

 single additional cell could be added to its size, whereas 

 where the oosphere remains in contact with the whole 

 or a portion of the parent plant after fertilization, a 

 certain amount of food is supplied by the parent which 

 gives the germinating plant a start in life, in fact, 

 supplies it with a reserve of food that it can draw upon 

 until it has built up assimilating structures ; hence, other 

 things being equal, it is not to be wondered at that the 

 free oosphere idea is not dominant. 



In some species of Fucus, in fact in most, a given 

 plant produces either antherozoids or oospheres only ; in 

 fact, the plants are male or female, hence cross-fertiliza- 

 tion is absolutely secured. 



In the remainder of the Cryptogams, as the mosses, 

 ferns, and club-mosses, the oosphere is motionless and 

 remains in contact with the parent plant at least until 

 germination commences, the antherozoids in all cases 

 being motile, as in Fucus, and reaching the oosphere 

 through the agency of water, and this point more than 

 any other constitutes the distinction between Cryptogams 

 and Phanerogams, the two primary divisions of the Vege- 

 table Kingdom. This in turn explains the absence 

 from Cryptogams of those showy portions of the flower 

 so conspicuous in most Phanerogams, and evolved for 

 the purpose of attracting insects in connection with 

 fertilization, the methods of which will eventually be 

 described in detail, Eemembering that the primordial 

 types of plant life were aquatic forms, the advantage of 

 voluntary movements of the portions concerned with 

 fertilization in such is obvious, the male organs or 



