636 MINNESOTA BOTANICAL STUDIES. 



XXXVIII. POLLINATION AND REPRODUCTION OF 

 LYCOPEBSICUM ESCIJLENTUM. 



Bruce Fink. 



The experiments presented in this paper were nearly all 

 performed three years ago, and it was then the purpose of the 

 writer to carry on the work through several years so as to in- 

 clude experiments on reciprocal crossing, close-pollination, 

 atavism and the prepotency of foreign pollen. It has not been 

 possible for me to carry on such experiments during the inter- 

 vening years because not permanently located during the 

 season where such work must be done. Hence, since there is 

 much of interest in the single year's work, it is thought best to 

 publish it, hoping that the experiments which could not be 

 completed in a single year may be brought to a conclusion at 

 some future time. 



I shall not attempt to enumerate the various papers consulted 

 in this work. Though a few of the experiments described 

 below have been tried before with tomatoes and some of the 

 remaining ones with other plants, I need not give references 

 to the published accounts, which are well known to botanists 

 generally. So far as I can ascertain, others of the experiments 

 have never been performed before. Of those that have been 

 tried, the results here recorded are not all in accord with those 

 published previously. 



During experiments in pollination, the plant operated on 

 must be covered while being used, and it is an advantage to 

 know just how long the plant must be under the screen, in 

 order to be certain that it is neither exposed to wind and in- 

 sects too soon nor kept covered longer than is necessary to 

 The experiment to ascertain the time necessary was conducted 

 as follows. Nine tomato flowers were castrated by removing 

 the stamens and marked (1), after twenty -four hours another 

 nine were castrated and marked (2), and after another twenty- 

 four hours a third nine were treated in the same way and 

 marked (3). The twenty-seven were pollinated at once so that 

 one third were pollinated forty - eight hours, another third 



