232 CANNA WABSCEWICZI. CHAP. VL 



not heavier, on the contrary a little lighter, than those from the 

 self-fsrtilised flowers, as was thrice ascertained. On one occasion 

 I weighed 200 of the crossed and 106 of the self-fertilised seeds, 

 and the relative weight of an equal number was as 100 for the 

 crossed to 101 5 for the self-fertilised. With other plants, when 

 the seeds from the self-fertilised flowers were heavier than those 

 from the crossed flowers, this appeared to be due generally 

 to fewer having been produced by the self-fertilised flowers, and 

 to their having been in consequence better nourished. But in 

 the present instance the seeds from the crossed capsules were 

 separated into two lots, namely, those from the capsules con- 

 taining over fourteen seeds, and those from capsules containing 

 under fourteen seeds, and the seeds from the more productive 

 capsules were the heavier of the two ; so that the above explana- 

 tion here fails. 



As pollen is deposited at a very early age on the pistil, gene- 

 rally in contact with the stigma, some flowers whilst still in 

 bud were castrated for my first experiment, and were afterwards 

 fertilised with pollen from a distinct plant. Other flowers were 

 fertilised with their own pollen. From the seeds thus ob- 

 tained, I succeeded in rearing only three pairs of plants of equal 

 age. The three crossed plants averaged 32 -79 inches, and 

 the three self-fertilised 2 '08 inches in height; so that they 

 were nearly equal, the crossed having a slight advantage. As 

 the same result followed in all three generations, it would be 

 superfluous to give the heights of all the plants, and I will give 

 only the averages. 



In order to raise crossed and self-fertilised plants of the second 

 generation, some flowers on the above crossed plants were crossed 

 within twenty-four hours after they had expanded with pollen 

 from a distinct plant ; and this interval would probably not be too 

 great to allow of cross-fertilisation being effectual. Some flowers 

 on the self-fertilised plants of the last generation were also self- 

 fertilised. From these two lots of seeds, ten crossed and twelve 

 self-fertilised plants of equal ages were raised ; and these were 

 measured when fully grown. The crossed averaged 36 -98, and 

 the self-fertilised averaged 37 '42 inches in height; so that here 

 again the two lots were nearly equal ; but the selMertilised had 

 a slight advantage. 



In order to raise plants of the third generation, a better plan 

 was followed, and flowers on the crossed plants of the second 

 generation were selected in which the stamens were too short tc 



