20 PLANT HYBRIDIZATION BEFORE MENDEL 



Linnaeus contends against the view of Morland and others 

 that the pollen itself enters the stigma, descends through the style. 

 and enters the ovary. This concludes the theoretical portion of 

 the dissertation. 



The first experiment which Linnaeus records consisted in re- 

 moving, "circa vesperam mense Augusti," all the stamens from 

 three flowers of Mirabilis longiflora, the other flowers having been 

 destroyed. The flowers emasculated were pollinated with pollen 

 from Mirahilis jalapa. The ovules grew but did not mature, 

 (p. 114.) 



"Another evening," he says, "I instituted the same experiment, but 

 pollinated (irrorabam) with the anthers of its own species, and all the 

 seeds matured." (8c, p. 114.) 



The next experiment is reported as follows : 



"in the month of January of this year Antholyza cunonia bloomed in 

 the window of my room, in an earthen pot, but bore no fruit, because 

 the air, enclosed within the walls, was unable to carry the pollen to the 

 stigma. On a certain day about noon, seeing the stigma absolutely moist, 

 I removed an anther with slender forceps, and lightly rubbed it over 

 one of the expanded portions of the stigmas. The spike of flowers re- 

 mained for eight or ten days, a fruit developing in that flower from 

 which I had previously removed the anther, and swelling to the magni- 

 tude of a bean. This therefore I opened, and saw, in but one of the three 

 cavities, many seeds developing, while the remaining two loculi were 

 absolutely void." {ib., p. 115.) 



In the following April, Linnaeus sowed seeds of Can?iabis in 

 two vessels grown by the window in two different rooms. In one 

 of the vessels, the male and female plants were allowed to grow 

 flowers and bear fruit, which matured in July. The seeds ob- 

 tained, on being planted, germinated in twelve days. In the other 

 of the vessels, all the male plants were removed, at the age when 

 it was possible to distinguish "the antheriferous males" from the 

 "pistilliferous females." The female plants put forth flowers, 

 the pistils of which lasted unfertilized as long as was required in 

 the other vessel for the fruits to come to maturity, when the 

 pistils, in a quite different manner, immediately withered, after 

 the males had entirely shed their pollen. The unfertilized plants 

 retained their pistils in a green, vegetative condition, and did not 

 wither until when, 



"after a long time, they were exposed to the afHatus of the male pollen. 

 Although the virgin plants produced large calices, these were empty of 

 living seeds. . . . From which I am quite sure that for the hemp deprived 



