EFFECTS OF POLLINATION. 



165 



56. Effects of liberal supply of 

 pollen. 



fruits. The larger fruit (Fig. 56) has all the cells de- 

 veloped and seed-bearing, while the smaller one (Fig. 57) 

 has seeds upon one side 

 only, and the other or un- 

 fertilized side is seedless 

 and nearly solid. The 

 original central division of| 

 this fruit is shown at A 

 This experiment has been 

 repeated several times with 

 substantially the same re- 

 sults. The fl o w e r s, of 

 course, were emasculated 

 in the bud, and were se- 

 curely covered with bags 

 to prevent any interference. 



Four important lessons are to be drawn from these 

 experiments : i. One-sidedness appears to be due to a 

 greater development of seeds upon the large side.* 

 2. This development of seeds is apparently due to the 

 application of the greater part of the pollen to that side. 

 3. An abundance of pollen applied 

 over the entire stigmatic surface, by 

 increasing the number of seeds in- 

 creases the size of the fruit. 4. The 

 pollen, either directly or indirectly, 

 probably stimulates the growth of 

 the fruit beyond the mere influence 

 of the number of seeds ; the growth 

 57. Effects of scanty of fhe solid part in Fig. 57 appears 

 supply of pollen. to indicate this. This secondary in- 

 fluence of the pollen in increasing the size of fruits, both 

 by means of increasing the number of seeds which nec- 

 essarily demand a larger envelope or receptacle and 



*For similar results in the pollination of apples, see Bull. 31, Mich. 

 Agr. Coll. 91 (1887). 



