Fig. 2. The reciprocal alternations of the development of the pistils and 

 anthers of avocado flowers. At right, flowers of Taylor, a typical Class A 

 variety; at left, flowers of Panchoy, typical of Class B. The upper photo- 

 graph shows the appearance of the two classes at the same moment in the 

 forenoon, the lower in the afternoon, when a different set of flowers is 

 open on each tree. In the morning, Class A flowers in their first opening 

 (upper right) are receptive to the pollen which is shed by Class B flowers 

 in their second opening (upper left). In the afternoon, Class A flowers in 

 their second opening (lower right) shed pollen which may be carried to the 

 receptive stigmas of Class B flowers in their first opening (lower left). 

 Photograph by Dr. A. B. Stout. 



