PLANT-LIFEGENERATION. 239 



tion, in which the children inheriting from 

 both parents, differ from each. Gradually 

 thus the grand diversity of Plant-life has 

 evolved and is still evolving. 



Now comes the curious fact that the flower 

 seeks to differentiate its two sexes as much 

 as possible for the purpose of fertilization. 

 Often the pollen is barren on its own flower, 

 but fertile on a different flower of the same 

 species. To some Orchids their own pollen 

 is poisonous, and self-pollination causes 

 death. Peculiar contrivances of Nature 

 have been pointed out by which the pistil 

 avoids its own stamen. The two organs 

 often mature at different times so that each 

 seeks its counterpart not at home but else- 

 where in another flower (the so-called dichog- 

 amy). Again, some Plants produce on the 

 same stalk both sorts of flowers, the self- 

 pollined and the other-pollined, the first be- 

 ing smaller, lower, seemingly less developed 

 than the second. Finally there is the com- 

 plete separation of the two sexes into two 

 different households (dioecious), each sex 

 having its own Plant. Pollination now oc- 

 curs through more external and more remote 

 means wind, water, birds, insects, even 

 snails, etc. 



The loves of the flowers have been celebrat- 

 ed by poets and lovers; but quite as certain 



