POLLINATION OF FLOWERS 



35 



Certain parts of the corolla are more brightly colored than the 

 rest of the flower. Butter and eggs is visited by bumblebees, 

 which are guided by the orange lip to alight just where they can 

 push their way into the flower. The bee, seeking the nectar se- 

 creted in the spur, brushes its head and thorax against the stamens. 

 It may then, as it pushes down after nectar, leave some pollen 

 upon the pistil, thus ef- 

 fecting self-pollination, 

 which is the transfer of 

 pollen from the anthers to 

 the stigma of the same 

 flower. Later, in visiting 

 another flower of the same 

 kind, the bee may leave 

 some more of the pollen 

 on the pistil of that second 

 flower. Cross-pollination 

 is the transfer of pollen 

 from the anthers of one 

 flower to the stigma of 

 another flower of the same 

 kind, — some say only if 

 the two flowers are on dif- 

 ferent plants. 



History of the Discov- 

 eries regarding Pollination 

 of Flowers. — Although the 

 ancient Greek and Roman 

 naturalists had some vague 

 ideas on the subject of pol- 

 lination, it was not until 

 the first part of the nine- 

 teenth century that a book appeared in which a German scientist, 

 Conrad Spreng'el, worked out the fact that the structure of cer- 

 tain flowers seems to be adapted to the visits of insects in that 

 it offers easy foothold, sweet odor, and desirable food in the 

 shape of pollen and nectar. Sprengel further discovered the fact 

 that pollen can be and is carried by the insect visitors from the 



Diagram to show how a bee polHnates but- 

 ter and eggs. A bumblebee, upon entering the 

 flower, rubs its head against the long pair of 

 anthers (A), then continuing to press into the 

 flower so as to reach the nectar at N, it brushes 

 against the stigma >S, thus pollinating the flower. 



