120 MANUAL OF TROPICAL AND SUBTROPICAL FRUITS 



In spite of numerous insect visits, however, a large number 

 of the stigmas are never pollinated, and it seems probable that 

 very little pollen is transferred from one flower to another. 

 Most of the stigmas receive their pollen from the anther (rarely 

 is more than one fertile) of the same flower. Cross-pollination 

 is in all probability uncommon. In damp cloudy weather the 

 pollen-grains swell and are much more difficult to dislodge than 

 when the weather is dry and sunny. After a heavy dew they 

 will be found in this swollen condition, but when the sun comes 

 out they return to their normal dry form. Protection of the 

 flowers from dew and rain by means of a canvas shelter did not 

 increase the production of fruit in the case of an experiment 

 carried out in Florida. 



Sometimes there is considerable differentiation in the size 

 of the pollen-grains. In most varieties the larger number, 

 however, are uniform in shape and size, plump and apparently 

 perfect. They can be germinated in sugar solution of the proper 

 density, and there is nothing to suggest that impotency is 

 common. 



From the fact that pollination ordinarily is scanty, it might 

 be assumed that productiveness could be increased by making 

 it more abundant. This has not, however, been found to be 

 the case, except when the pollen was obtained from a tree of a 

 different variety (cross-pollination) ; under these conditions 

 there was a somewhat better yield. The total number of 

 flowers produced is so enormous that it is of little importance 

 whether all are pollinated or not. Seedling mangos, which are 

 not pollinated more abundantly than budded varieties, nor 

 furnished with a greater number of anthers, nor, so far as can 

 be ascertained, with pollen of greater potency, often set many 

 more fruits than they can carry to maturity. This has been 

 noted also with several grafted kinds, such as Bennett and 

 Cambodiana. 



Sometimes the entire tree comes into bloom at one time, 



