CHAP. I. 



PRIMULA VERIS. 



21 



good with some other species of Primula. Conse- 

 quently my anticipation that the plants with longer 

 pistils, rougher stigmas, shorter stamens and smaller 

 pollen-grains, would prove to be more feminine in 

 nature, is exactly the reverse of the truth. 



In 1860 a few umbels on some plants of both the 

 long-styled and short-styled form, which had been 

 covered by a net, did not produce any seed, though 

 other umbels on the same plants, artificially fertilised, 

 produced an abundance of seed ; and this fact shows 

 that the mere covering in itself was not injurious. 

 Accordingly, in 1861, several plants were similarly 

 covered just before they expanded their flowers ; these 

 turned out as follows : 



TABLB 5. 



Judging from the exposed plants which grew all round 

 in the same bed, and had been treated in the same 

 manner, excepting that they had been exposed to 

 the visits of insects, the above six short-styled plants 

 ought to have produced 92 grains' weight of seed 

 instead of only 1 3 ; and the eighteen long-styled 

 plants, which produced not one seed, ought to have 

 produced above 200 grains' weight. The production of 

 a few seeds by the short-styled plants was probably due 

 to the action of Thrips or of some other minute insect. 

 It is scarcely necessary to give any additional evidence, 

 but I may add that ten pots of polyanthuses and 



