SEED-NUMBER AND FRUIT-SIZE 343 



changed. For capsules the results obtained vary. Thus, with Iris, we 

 find that as the fruit increases in size and the seeds in number, the 

 seeds add to their weight and size, whilst with Canna they remain 

 unchanged. But when a capsule matures only one or two large seeds, 

 as with the Horse-chestnut (/sculus\ the seeds of the double-seeded 

 fruits are smaller and lighter than those of the single-seeded capsules. 



(7) However, the study of the relation between the number and 

 size of seeds and the proportions of the fruit opens up a difficult 

 problem. Questions concerned with the variation in the number of 

 seeds in the same plant at once present themselves, and these cannot 

 be answered without an inquiry into the abortion of ovules and the 

 failure of young seeds. Much depends in the history of the fruit 

 on whether the original pollination of the stigma resulted in the fertilis- 

 ation of the ovules or merely served to stimulate the growth of the 

 pericarp. These matters are dealt with in the succeeding chapter. 



