322 PLANT-LIFE 



Notwithstanding the devices employed by herma- 

 phrodite flowers to ensure cross-fertilization, it seems 

 probable that in most cases self-fertilization happens 

 occasionally, and we know of many flowers which have 

 arrangements whereby self-fertilization can take place 

 if crossing is not secured, or even as supplementary 

 thereto. Perhaps one reason for the remarkable success 

 of the Compositse (p. 217) is their ability to ripen all 

 possible seeds, by supplementing cross- with self-pollina- 

 tion. In their case the stigmas, before they finally quit 

 business, even if they have been previously pollinated, 

 curl over and search anthers for pollen. 



The importance of insects to flowers, and of flowers 

 to insects, is, then, enormous, and we may well marvel 

 at their interdependence and their mutual adaptations. 

 But before we leave the subject of pollination, we must 

 note that animals other than insects are sometimes 

 engaged in the work. Of what is called Ornithophyly 

 (Gr. ornis, ornithos, a bird) we have no British instances, 

 but in tropical and South America humming-birds 

 engage in pollination, and the same is true in regard to 

 the honey-birds which occur in the tropical regions of 

 Asia, Africa, and Australia. It has been observed that 

 a certain plant, Freycinetia, found in the Malay Archi- 

 pelago, is pollinated by the flying-fox; also that snails, 

 in a few cases, are useful to plants. The latter are 

 credited with the pollination of the half-buried flowers 

 of Aspidistra, and also those of the Golden Saxifrage 

 {Chrysosflenium) . 



Turning now to the concluding theme of this chapter, 

 we shall see, to a brief extent, how the perpetuation of 



