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TORREYA 



elongate considerably, and there is a slight enlargement of all parts of the 

 flower. 



When it opens the second time (Fig. 7), the flower has an appearance 

 quite distinct from that which it presented during its first anthesis. The petals 

 bend outward even farther than before, until they become slightly reflexed. 

 The stamens now no longer lie inconspicuously in contact with the petals, but 

 stand up prominently in the center of the flower. The three innermost stand 

 quite erect and parallel to each other ; they rise above the stigma and almost 

 conceal it. When the flower closed at the end of its first opening, they were 

 shorter than the pistil ; now they exceed it in length. The six outer stamens 

 rise obliquely around the central group. Soon after the flower has opened, 

 often before it has fully expanded, the anthers begin to open and to shed their 

 pollen. Each anther dehisces by means of four elastic valves (Fig. 8), which 



Figs. 2-4.— Fig. 2. Bud of aguacatillo one day before opening. Fig. 3. Flower closed 

 after first opening. Fig. 4. Flower closed after second opening. All x 5. 



were already prominent on the closed anthers during the first expansion of 

 the flower. There are two long valves for the outer anther cells, and between 

 them two much shorter valves for the two inner anther cells. These valves 

 become detached from the walls of the cells everywhere except at their narrow 

 upper ends. They rise upward and outward until they stand above their 

 respective cells and extend slightly above the end of the anther. They would 

 project far more prominently if they did not shrink so strongly upon opening. 

 The mass of pollen from each cell remains attached to the erstwhile inner 

 surface of the valve, which finally becomes convex, and is thus prominently 

 exposed at the tips of the stamens. The stigma, which was already discolored 

 at the beginning of the second anthesis, soon becomes quite black and withered. 

 It appears to be no longer receptive and is largely concealed by the stamens. 

 During its second opening, the flower is purely staminate in function. 



If one examines a number of trees at any time while their flowers are in 

 full anthesis, he will find that the flowers of some appear to be in their first 



