0. K HECTOR. 5 



such flowers set no grain. It is a matter of common observation 

 that a far larger number of empty husks are to be found in the 

 heads of Aus varieties than in Aman varieties, due probably to 

 the wet weather which often occurs in Lower Bengal when the 

 Aus rices commence to flower. 



In about four days a whole inflorescence will ordinarily have 

 been pollinated in the way described above. 



III. — Cross-Fertilisation. 



Though the above is the normal process, the method of 

 pollination by no means precludes the possibility of cross-polli- 

 nation taking place. It has been pointed out above that the 

 stigmas are not infrequently to be seen protruding from between 

 the open glumes, while the stamens have not lost all their pollen 

 when they assume the hanging position, so that there is every 

 possibility, should self-pollination have failed, of cross-pollination 

 resulting, and we have collected evidence to prove that it is 

 by no means unknown, and under favourable weather conditions, 

 bright sunshine with a gentle breeze, possibly takes place to 

 a greater extent than we have as yet been able to prove. It is 

 practically certain, however, that such cross-pollination as does 

 take place is confined to neighbouring plants in the same plot, 

 and that the pollen of one plant seldom if ever succeeds in 

 reaching the stigma of a plant more than a foot or two away. 



In the following paragraphs an account is given of the 

 evidence we have so far collected as to the extent to which cross- 

 pollination has been found to occur. 



In 1911 single plant cultures of 150 types of transplanted 

 Aman varieties were grown at Dacca farm from single plants 

 selected in the season 1910. No cases of splitting crosses were 

 found in these, and all were passed as pure at harvest time, but 

 in four plots a few variant plants were found. Subsequent 

 examination, however, in the laboratory, of the seed of certain 

 white-grained varieties, proved that in some, red-grained seeds 

 were to be found which had escaped detection at harvest time, 

 and possibly there were others which were not discovered. Six 



