Arrangements for Securing Union of Sexes 323 



told me why one man is a carpenter and another a farmer; or why 

 the Latin races are artistic while the Teutonic are practical; or 

 why the Germans are the best scientific investigators in all the 

 world. 



The symmetry of my subject would seem to demand that I add 

 to these paragraphs on color, odor, and nectar, another devoted 

 to the mechanical arrangements in flowers in relation to cross 

 pollination. But I despair of giving any adequate idea of this 

 subject in the space that remains at my command, and it must 

 suffice to say that such arrangements are both remarkable and 

 innumerable, involving not only the most extreme modifications 

 in all of the parts, but such special features as sensitively-bend- 

 ing stamens (in the Barberries), closing stigmas (perhaps, in 

 Mimulus), springing stamens (as in Mountain Laurel), explosive 

 stamens (as in Mallows), forcibly-projected pollen-masses (as in 

 some Orchids), and others as striking, which the reader may 

 follow as far as he pleases through the many good books devoted 

 to the subject. 



It is doubtless sufficiently obvious why insects are the animals 

 most used for cross pollination by plants, for their small size, 

 active flight, and especially their nectarivorous habits, make them 

 especially available for this purpose. But it must at the same 

 time be remembered that those very features have doubtless in 

 large part been evolutionarily acquired in conjunction with the 

 corresponding features of the flowers. Insects, however, are not 

 the only animals thus utilized, for certain nectarivorous birds, of 

 which the Humming-bird is the most familiar example, cross 

 pollinate flowers in quite the same manner as the insects. Every- 

 body has seen in our own gardens the Trumpet-creepers and 

 Nasturtiums and Scarlet Salvias visited by Humming-birds. 

 There are plenty of tropical flowers, displaying for the most part 

 large tubular corollas, abundant nectar, and scarlet colors, which 

 have a form, size, and shape well suited to the flying-habits of 

 those birds. Among other animals that effect cross pollination 



