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MEMOIRS OF THP: XEW YORK BOTAXICAL GARDEN 



EXPLANATION OF PLATE 28 



1. During irregular flower-behavior, flowers are frequently shedding 

 pollen (flower at lower left) while others on the same branch are open 

 for the first or female opening (see flowei*s at apex of branch). Then 

 there is chance for close-pollination. Such pollinations do not necessarily 

 insure setting of fruit. 



2. For some varieties fruits often start to mature to nearly every 

 flower, but most of these fruits soon fall and at the harv^est the crop may 

 be scant. This condition has led many growers of avocados to believe 

 that the main problem in avocado growing is to provide cultural condi- 

 tions which enable trees to hold and mature fruit. This may often be 

 the case. The flower behavior of these varieties is A or B as for other 

 varieties and is as fully dichogamous. In certain tests, the fruits set 

 when the flowers had been enclosed in bags. Further tests are needed 

 to determine if in these varieties fruit will start to develop without pol- 

 lination or with only self-pollination and whether adequate yields may be 

 had without cross-pollination. 



3 and 4. The flowers of avocados are borne on lateral branches. After 

 yielding flowers for a time, the main axis may produce a few leaves and 

 then resume flowering, as shown here. When the flowering period is over, 

 nearly always an end bud emerges as a vegetative bud, as shown at 4. 

 The fruit therefore hangs from main stems which are leafy at their tips. 



The cluster of flowering branches may continue to bloom for several 

 weeks or even months. If as many as two fruits mature in each cluster, 

 the tree bears a large crop. An increase in the number of flowers that 

 are properly cross-pollinated will without a doubt lead to greater setting 

 of fruit. 



