CROSS-FERTILIZATION OF PLANTS. 



263 



Some Devices Tending to Insure Cross-Fertilization of 



Plants. 



Maurice Ricker. 



The oak has a wind-pollinated flower. In some plants the pollen is 

 carried by water. A large number of the conspicuous flowering plants 

 are pollinated by insects, bees taking the leading part, though moths, 

 butterflies, flies, beetles and bugs do much of the work. Some of the 

 deep throated flowers, as the honey-suckle, are pollinated by the hum- 

 ming bird. Other especially adapted plants are said to be pollinated 

 by snails. 



Christian Konrad Sprengel was a pastor in a German parish until he 

 neglected his duties, to the extent that he lost his position. This neglect 

 came about through his love of the study of plants. He then made a 

 precarious living by teaching the languages and mathematics, and con- 

 tinued his investigations, the results of which appeared in 1793 in a vol- 

 ume entitled "Das Endeckte Geheimnis der Natur." He shows in this 



Fig. 24. 



book a perfect understanding of the nature of fertilization and believes 

 that insects play a part in putting pollen upon the stigma. Waetcher 

 in a memoir in 1801, taught the structure of the orchid pollen-mass, or 

 pollinia, as it is now called, and showed that it must be removed by an 

 insect. 



It remained for Darwin to discover the real secret of nature. He 

 approached the subject through experimentation upon flowers fertilized 

 by their own pollen as contrasted with those which are fertilized by the 

 pollen of other flowers. His book on the "Fertilization of Orchids by In- 

 sects" appeared in 1862, nearly 70 years after Sprengel's work was first 

 published in Berlin. We have illustrated the difhculties in the way of 

 accepting Sprengel's work and Darwin's final solution of the problem by 

 four charts, after Gibson. 



