SKUTCH : FLOWERS OF THE AGUACATILLO 



113 



opening while those of others are in their second opening. All the myriads of 

 open flowers on any one tree are always found to be in the same stage — either 

 all in the first opening or all in the second. Thus it is possible to recognize two 

 classes of trees, which, following Stout's work (1927) on the avocado, we 

 may designate "A" and "B." If these two kinds of trees are watched during 



Figs. 5-8. — Fig. 5. Flower of aguacatillo in first opening, from side. Note declined 

 stamens and unopened anthers ; x 5. Fig. 6. The same, from above ; x 5. Fig. 7. Flower in 

 second opening from side. Note ascending or erect stamens and opened anthers ; x 5. 

 Fig. 8. Dehiscent anther of the outer series of stamens, with lifted valves and escaping 

 pollen ; greatly enlarged, g — nectar gland, o = pistil, p — petal, s = sepal, st — stamen. 



two consecutive days, with a few of their flowers marked with bits of thread 

 so that they can be recognized in their different stages, a pattern of behavior 

 can be formed. 



Class A comprises those trees whose flowers open for the first time at 

 dawn, and for the second time toward the end of the following morning. The 

 petals of the hitherto unexpanded buds begin to separate from each other at 



