168 



MEMOIRS OF THE jS'EW YOUK BOTANICAL GAKDEK 



orchard tree is likely ever to receive. If trees of these varieties 

 readily set fruit without cross-pollination, the tented trees 

 should have borne heavy crops. 



Here the comparisons of yields are between teAted trees with 

 abundant and almost complete enforced self- and close-pollina- 

 tion and trees submitted to open pollination. Honey bees were 

 not kept in the vicinity of Mr. Krome's orchard and they were 

 rarely seen in it. The orchard pollination was accomplished by 

 wild insects and chiefly, it would appear, by certain flies and 

 wasps. Proper cross-pollination between A and B varieties may 

 have been frequent or scant. For an adequate comparison, the 

 results obtained for tented trees should be checked against those 

 obtained when there is repeated and abundant cross-pollination 

 between varieties reciprocating in flower behavior. Xo such 

 data were obtained and such data would be difficult to obtain. 

 Even when two trees of different and reciprocating varieties are 

 enclosed in one tent, individual bees may not freely make the 

 cross-visitations necessary to proper pollination. Further mat- 

 ters concerning the relations of insects to pollination of avo- 

 cados has been discussed in considerable detail elsewhere (Stout, 

 1924 c, and 1925). 



Some results of tenting experiments with avocados con- 

 ducted at Point Loma, California (Clark, 1923, 1924), indicate 

 that under certain conditions some A^arieties may set consider- 

 able fruit or perhaps yield good crops to enforced self- and close- 

 pollination by bees. The daily sequence of blooming reported 

 for Point Loma by Clark as "usual" for Fuerte and Spinks 

 is the irregular and off-stride and exactly the reverse of the 

 normal for these varieties. Possibly at the Point Loma location 

 proximity to the ocean may very generally give an off-stride 

 blooming that may somewhat favor fruit-setting to self- and 

 close-pollination. 



A few varieties of avocados will frequently set fruits for 

 nearly every flower. They will do this when the flowers are en- 

 closed in a paper bag so that all cross-pollination is impossible 

 and all insects visitations are prevented. As many of these 

 fruits api)areiitly contain no embryos, they evidently set without 

 pollination and fertilization. Usually these fruits soon fall. In 



