THE COURSE OF BIOLOGIC EVOLUTION. 41 



carbonic dioxide of the air which is the chief nourishment of 

 plants. The separation of the sexes, the transition from spore- 

 bearing to seed-bearing plants, the development of a closed 

 ovary for the protection of the germ, and of floral envelopes 

 for the protection of the stamens and pistils, all tended to per- 

 fect the reproductive function and render a higher type possible. 

 These influences were therefore all normal and legitimate in 

 acting directly upon the essential properties of the organism , 

 and had no extra-normal or illegitimate influences come in to 

 modify the results these direct ends would have been the only 

 ones attained. Vegetation would doubtless have still been 

 green as now, there would have been forests of large trees with 

 strong solid trunks and umbrageous foliage ; there would have 

 been green grass and rushes, rank and luxuriant herbage, 

 stately palms and graceful ferns, even as now, but this would 

 have been all. Two of the leading features of' the actual vege- 

 tation would have been wanting, viz., showy and fragrant 

 flowers and highly colored, pleasantly flavored, and nutritious 

 fruits. 



A large, showy, or fragrant .blossom is of no direct use to a 

 plant. Indeed its nourishment is an expense to the normal 

 growth of the plant. Still greater is the cost of the abundant 

 nutritious matter in many fruits. In both these cases the value 

 to the plant is indirect, and when we stud}- the subject deeply 

 we find that the cause of the development of such organs is 

 a sort of teleological or final cause. Beautiful flowers and 

 edible fruits are extra-normal or illegitimate products of nature, 

 and those who fail to see this have but a crude and imper- 

 fect conception of the course of evolution. 



Fortuitous \~ariation. — In a certain sense every influence 

 that affects an organism is legitimate, and we have seen that 

 the several great types have been brought into existence by 



