FLORAL MECHANISMS 



89 



TRUMPET 



humming-birds. The mechanism acts precisely 

 like that of the iris, scraping pollen from an 

 a r r i V ing 

 humming- 

 bird, but 

 closing as 

 he w i t h - 

 draws with 

 h o m e - 

 grown pol- 

 len on his 

 head. 



The trum- 

 pet-creeper illustrates a principle in the fertilisa- 

 tion of flowers which we should point out. I have 

 noticed that our own trumpet-vine rarely sets any 

 seed-pods, and find in this fact the illustration of 

 a principle in the fertilisation of flowers which 

 should be explained. 



In general, flow^ers are more easily fertilised by 

 pollen taken from the flowers of another plant — 

 less sensitive to pollen taken from another part of 

 their own plant, and scarcely sensitive or entirely 

 sterile to pollen taken from their own anthers. As 

 a demonstration, Fritz IMiiller fertilised a Brazilian 

 species of the Bignonia, which is the family name of 

 our trumpet-creeper, with the following result: 



