POLLINATION OF THE MANGO. 



bodies, and although a few grains were nearly always present no con- 

 siderable quantities were ever seen. 



While four beetles were taken on mango flowers, one of them with 

 considerable regularity, it is doubtful whether any of the Coleo.ptera 

 plays an important part in pollination. The common species was 

 Euphoria sepulcralis Fab., a grayish black, clumsy insect with a broad 

 body about 1 centimeter long. Chauliognathus marginatus Fab., a 

 slender, much smaller, and more active insect, was seen in one locality 

 on several different occasions. Pachnaeus opalus Oliv., a pale-green 

 species slightly under 1 centimeter in length, was taken only once, as 

 was also Clirysobothris chrysoela 111., a small black species with six 

 shining red spots on the wing cases. It is doubtful whether either of 

 these has a bearing on pollination. 



In spite of the visits of the above-mentioned insects, a large pro- 

 portion of the stigmas are unpollinated, and it seems probable that 

 very little pollen is transferred from one flower to another, most of the 

 stigmas probably receiving pollen from the anther of the same flower. 

 Examinations were made of numerous flowers to determine the num- 

 ber of pollen grains which had lodged on the stigma. For this purpose 

 those flowers were chosen in which all, or practically all, of the pollen 

 had been shed from the anther, but in which the stigma had not yet 

 commenced to turn brown. Such flowers had every opportunity 

 to be pollinated and where they were found to be unpollinated at that 

 time there was very little chance of their being pollinated at all, since 

 the stigma would have soon been past the receptive stage. An exam- 

 ination of 429 such flowers gave the following results: 



Number. 



Stigmas unpollinated 223 



On which 1 grain was found 84 



On which. 2 grains were found 47 



On which 3 grains were found 26 



Number. 



On which 4 grains were found 20 



On which 5 grains were found 13 



On which 6 grains were found 5 



On which 7 to 10 grains were found 5 



The flowers examined were taken from trees in different sections 

 around Miami and under widely differing weather conditions, so that 

 the results probably can be considered a fair average of normal 

 pollination for this region. Differences were noted in the comparative 

 abundance of pollination on different days and different trees, of 

 course, but with one exception these seemed scarcely important 

 enough to warrant notice. After a rather strong wind which blew 

 for about two days, a higher per cent of pollination was found on 

 the Sandersha variety than at any other time. Coupled with this 

 was the presence of large quantities of foreign matter on the pistils, 

 principally fine particles of sand. The flowers had been thrashed 

 about considerably in the wind, and more pollen had reached the 

 stigmas than was normally found in calm weather. 



In damp, cloudy weather the pollen grains swell and are much 

 more difficult to dislodge than when the weather is dry and sunny. 



