i8o ANCIENT PLANTS 



of the vital organs may show a development in a direc- 

 tion contrary to what has hitherto seemed advance. 

 Until recently flowers and their organs have appeared 

 to us to be specialized in the more advanced groups on 

 such lines as encourage "cross fertilization". In "cross 

 fertilization ", in fact, has appeared to lie the secret of the 

 strength and advance of the races of plants. But modern 

 cytologists have found that many of the plants long 

 believed to depend on cross fertilization are either self- 

 fertilized or not fertilized at all! They have passed 

 through the period when their complex structures for 

 ensuring cross fertilization were used, and though they 

 retain these external structures they have taken to a 

 simpler method of seed production, and in some cases 

 have even dispensed with fertilization of the egg cell 

 altogether. The female vitality increased, the male be- 

 comes superfluous. It is simpler and more direct to 

 breed with only one sex, or to use the pollen of the same 

 individual. Many flowers are doing this which until 

 recently had not been suspected of it. We cannot yet 

 tell whether it will work successfully for centuries to 

 come or is an indication of "race senility". 



Whether in the epochs to come flowering plants will 

 continue to hold the dominant position which they now 

 do is an interesting theoretical problem. Flowers were 

 evolved in correlation with insect pollination. One can 

 conceive of a future, when all the earth is under 

 dominion of man, in which fruits will be sterilized for 

 man's use, as the banana is now, and seed formation 

 largely replaced by gardeners' " cuttings ". 



In those plants which are now living where the com- 

 plex mechanisms for cross-fertilization have been super- 

 seded by simple self-fertilization, the external parts of the 

 more elaborate method are still produced, though they are 

 apparently futile. In the future these vestigial organs 

 will be discarded, or developed in a more rudimentary 

 form (for it is remarkable how organs that were once 

 used by the race reappear in members of it that have 



