2 

 pel's observations. Dai win's work "On the Fertilization of 

 Orchids,"' published in 1862, gave un impetus to the study 

 which hSs continued till the present time. D'Aarcy W. 

 Thompson in 1883 gives the titles of 814 papers; J. Mac- 

 Leod, 638 papers from 1883 to 1890. 



Among the numerous workers in this line I can only 

 mention a few: Hermann Mueller, Fritz Mueller, Axell, 

 Hildehrand, Lubbock, Grant Allen, Delpino, Kerner, 

 von Marilaun, Forbes, Bennett, Darwin, Loew and Lud- 

 wig. In our own country: Gray, Trelease, Riley, Foerste 

 and Beal, Weed. The work of Mr. Charles Robertson, of Carl- 

 iaville, Illinois, deserves__ special mention. He has done an 

 enormous amount of careful and conscientious work. No 

 other American botanist has collected such valuable data. 

 Those interested in this subject should consult these papers. 

 At the out set it is well to have a clear 

 understanding of what is meant by pollin- 

 ation and fertilization. Pollination is 

 simply the conveying of pollen from the anther to the 

 stigma. Fertilization occurs after the pollen has reached the 

 stigma; it is the impregnation of the ovule. Fertilization 

 has been defined as the union of protoplasm of two diflferent 

 cells. 



Adaptatibusfor ^° °^o«* ^'S^^'" P'^^^^s both kinds 



. „ J . of organs occur in the same flower,' 

 Sexual Reproduction. ° 



so that it is possible to have close 



fertilization — autogamous; — or from flower to flower in the 

 same plant — geitonogamous. But the rule is to be cross fer- 

 tilized — xenogamous. 

 Conditiofls opposed DIOECIOUS. Stamens and pistils oc- 

 To self Fertilization. ^''^ ""^ difl'erent individuals, as in 

 willow. 



