254 THE STRUCTURE OF FLOWERS. 



finders " peculiar to intercrossed flowers are more or less 

 reduced, if not absent. 



4. The partial or total arrest of the corolla. 



5. The mature stamens of the expanded flower retain in 

 many cases the incurved, i.e. an arrested position, which 

 they had in bud ; the anthers thus remain in contact with 

 the stigmas. 



6. The stamens are often reduced in size and number, 

 and the pollen in quantity. 



7. The pollen tubes may often be seen to be penetrating 

 the stigmas, either from grains still within the anther-cells, or 

 evidently derived from those of the same flower. 



8. The styles are shortened, and the stigmas are situated 

 appropriately for direct pollination from the anthers of the 

 same flower. 



9. The partial arrest of the corolla and stamens in their 

 rates of development, allows the pistil to mature with com- 

 parative rapidity. 



10. The consequent early maturation of the stigma, so as 

 to be ready before or simultaneously with the dehiscence of 

 the anthers. 



11. Little or no scent. 



12. Decrease in siz:e or total absence of honey glands, 

 with corresponding little or no secretion of honey.* 



Notwithstanding these various indications of degradation, 

 such flowers are often correlated with special alterations 

 which secure self-fertilisation without a chance of failure 

 — a precariousness which almost always exists in flowers 

 adapted to insects. Thus — contrary to the old but erroneous 



* Miiller, in his "General Retrospect" (Fertilisation, etc., p. 591), 

 also gives a number of modifications, mostly referred to in the text above, 

 of what he describes as " the countless ways in which plants revert to 

 self-fertilisation in default of suflScient insect visitors." 



