202 



MEMOinS OF THE XEW YORK BOTAXIC.\L GAKDEX 



EXPLANATION OF CHART 10 



As shown here in this record for the season, the trees of Trapp under 

 observation Avent through the season of bloom without a single moment of 

 time when firsts and seconds were open together. The seconds shed their 

 pollen during the forenoon and were through and fully closed (see upper 

 view in plate 27) from 45 minutes (February 10) to as long as three 

 hours (March 2nd) before the firsts began to open. There was on the 

 basis of this record never a chance for close-pollination. 



In comparison with most other varieties of Class B the Trapp has the 

 first-period anthesis start late in the afternoon when there is only little 

 pollen being shed from A varieties and when the activities of the insects 

 usually working avocado flowers are greatly reduced. Frequently the 

 firsts open after dark but on most days they were fully closed when ob- 

 servations were made as late as 9 : 00 P. M., and with one exception they 

 were fully closed when obsen-ations are made before 7:00 o'clock A. M. 

 the following day. 



In off-stride blooming a set of flowers in the second period of open- 

 ing may remain open and shed some pollen for the greater part of two 

 days (see Febraary 12 and 13th) during which no firsts open. A set 

 which skipped first opening may open as singles the next day but fail 

 entirely to shed pollen (see ]\Iarch 4th), or such a set or part of a set may 

 shed some pollen (see record for I\Iarch 5th). 



If fruit will set on trees of the Trapp without cross-pollination, it 

 seems certain that the opening of firsts late in the afternoon with the 

 next opening on the following forenoon, in this varietj^ at least, favors 

 self-fertilization. It is, however, possible that some fruit may set without 

 any fertilization. 



