2 BULLETIN 542, U. S. DEPARTMENT OF AGRICULTURE. 



(CoTletotrichum gloeosporioides Penzig), a fungus which frequently 

 attacks the young flower spikes and destroys them. Its activities 

 are largely dependent upon weather conditions, being greatest when 

 the air is warm and moist, with frequent showers. This question 

 was studied by McMurran. 1 Sometimes the flowers appear in dry 

 weather and escape unharmed, but a few days of showery weather 

 later on may provide favorable conditions for the development of 

 the fungus, and the young fruits may be destroyed or badly disfigured 

 and deformed. In some seasons trouble from this source is relatively 

 slight, in others serious. 



Allowing for injury from this cause, which is an important factor 

 in the production of mangos, it was believed that there must be 

 other factors responsible for many of the crop failures of the Mulgoba 

 and other varieties. Several Indian and West Indian writers have 

 suggested that defective pollination might be one of the most im- 

 portant factors, and it was for the purpose of determining its precise 

 importance that the investigations herein described were under- 

 taken at Miami, Fla., in 1915 and were continued in 1916. In 

 connection with any studies such as this on the pollination of fruit- 

 bearing trees, two papers by M. B. Waite 2 should be examined. 



THE MANGO FLOWER AND ITS POLLINATION. 



It has been affirmed by Hartless 3 that the mango is largely, if 

 not solely, wind pollinated. Other writers have also advanced the 

 opinion that the wind is an important agent in effecting pollination. 



It seems evident, however, that the mango has none of the charac- 

 teristics of an anemophilous plant, but, on the other hand, presents 

 well-developed adaptations to insect pollination, so that it may be 

 considered truly entomophilous. The amount of pollen which 

 reaches the stigmas was found to be slightly greater in one instance 

 on a very windy day; but this undoubtedly was due to the brushing 

 of one flower against another or against the surrounding foliage, 

 the panicles being thrashed violently about. 



Some of the principal characteristics of an anemophilous plant 

 are that (1) the pollen is abundant, compensating for the enormous 

 waste in transport; (2) the pollen grains are dry and incoherent, so 

 that they are easily carried by the wind; and (3) the stigmas are 

 commonly large and bushy and freely exposed, so as to have every 

 chance of catching the floating pollen grains. The mango has none 



1 McMurran, S. M. The anthracnose of the mango in Florida. U. S. Dept. Agr. Bui. 52, 15 p., 4 fig., 

 4 pi. 1914. 



2 Waite, M. B. The pollination of pear flowers. U. S. Dept. Agr., Div. Veg. Path. Bui. 5, 110 p., 5 fig., 

 12 pi. 1894. 



Pollination of pomaceous fruits. In U. S. Dept. Agr. Yearbook, 1898, p. 167-180, fig. 32-44. 



1899. 



3 Hartless, A. C Mango crops and some factors influencing them. In Agr. Jour. India, v. 9, pt. 2, 

 p. 141-159. 1914. 



