14O 1I.()\\IK> 01 THE FIELD AND FOREST. 



Now the pistil grows up through this narrow tube, and 

 at last protrudes beyond it. At first glance it would seem im- 



sible that the flower should not be self-fertilized. But by 

 looking closer it will be found that the pollen all ripens and 

 falls out of the anther before the pistil grows up to the end of 

 the tube where the pollen is produced. Moreover, the stigmatic 

 surface is on the inside of the two lobes which are made by 

 splitting the end of the pistil down. As the pistil pushes up 

 through the tube, by the anthers, these surfaces are shut close 

 together, face to face, so that the pollen could not possibly reach 

 them. These lobes open and expose their stigmatic surface 

 only when they have protruded quite beyond the end of the 

 pollen-bearing anther tube. 



The plate shows not only the position of this organ, but 

 also in the newer flowers at the top the anther tube with no 

 pistil, and, lower down, flowers where the pistil has completed its 

 growth and expanded its yellow-lobed stigma ready for polleniza- 

 tion. Now it is evident that any particular flower must be 

 fertilized by pollen from a flower younger than itself. Associated 

 with this arrangement of parts of which I have spoken are 

 adaptations for securing help in transferring the pollen from the 

 younger to the older flowers, such as a supply of nectar secreted 

 at the bottom of the tubular corolla, and advertised by the bril- 

 liant color of the flower. As has been shown by Mr. Darwin, 

 Prof. J. E. Todd and others, in the case of other species of 

 Lobelia, bees visit the flowers in search of the nectar, and getting 

 their backs dusted with pollen from the end of the anther-tube 

 which arches out over them, carry it to older flowers where the 

 pistil is ready to receive it. 



