176 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



EXPLANATION OF PLATE 25 



In the second or male anthesis, avocado flowers are as shown here. 

 The contrast to their appearance in the first opening is marked (com- 

 pare with PLATE 24). Now the stamens are larger and they are more erect. 

 Part of them stand above and closely about the pistil, which is often dis- 

 colored and shriveled, as shown in the upper insert. During the second 

 opening pollen is shed by uplifted valves shown here and in the lower 

 insert. In its second opening the flower functions as a male. 



The principal stages in the cycle of dianthesis typical of each flower 

 of any avocado tree may be traced in the plates 25 and 26 as follows : 



No. L Flower bud not yet old enough to open. 



No. 2. Flower in the first or female opening. 



No. 3. Flowers that have been open for the first period and are now 

 closed in the interval before it is time to open for their second period. 



No. 4. Flowers open for the second or male opening. 



No. 5. Flowers closed after the second opening. The cycle of flower 

 behavior is complete. 



The flowers (except the in.serts) here shown are of the Taylor variety 

 and the picture was taken at 3 :00 P. M. In this variety normally all the 

 flowers open in the afternoon are those open for the second time. The 

 entire tree functions only as a male in the afternoon. The dichogamy is 

 synchronous. This condition greatly limits or even prevents pollination 

 between flowers of the same tree or of trees of the same clonal variety. 



At h is shown a pistil at the time of the second antliesis, exhibiting the 

 dead and shriveled tip as it frequently appears at this time. 



At c are shown several stamens with uplifted valves on which pollen 

 is exposed. 



