THE FLOWER BEHAVIOR OE AVOCADOS 



157 



of varieties. The varieties standing first or last in the two 

 groups of A and B remain thus day after day with decided uni- 

 formity. 



Irregular axd abnormal flower-behavior 

 The particular behavior of sets of avocado flowers, as to pre- 

 cise time of opening, duration of the opening, period of over- 

 lap and lapse between sets, is affected by weather conditions and 

 particularly by changes in temperature. In extreme cases the 

 entire sequence of normal behavior is thrown entirely out of 

 stride and the action of the flowers becomes very irregular. 



WHien the temperatures tend to be low the hours of opening 

 are comparatively late in the day (chart 3). With higher day 

 and night temperatures and with increasing hours of daylight 

 the hours are earlier (see chart 4). Thus the "clock" hours for 

 opening tend to be later during the earlier part of the season 

 of bloom (January and February) and earlier in the day during 

 April and May. This general trend to earlier hours is shown 

 when the daily performance of a single variety is charted for an 

 entire season of bloom (see chart 9). 



A change to a lower temperature at night will frequently 

 result in the differences recorded in charts 3 and 4. Here the 

 relative behavior of the two sets of flowers for each variety, the 

 relative behavior for different varieties as such, and the relative 

 performance of the A and of most of the B groups remain quite 

 uniform. The hours of opening for all merely shift to later clock 

 hours. 



With an increasing severity of changes in temperature, flower 

 behavior becomes correspondingly more abnormal until the daily 

 sequence of sets is thrown out of stride and the flowers belonging 

 to one or more sets respond with marked irregularity. 



Even under slight lowering of temperatures, for such varie- 

 ties as Trapp and Taft 's Golden, the first or female opening may 

 be omitted by an entire set or a part of a set (see in chart 3). 

 Such flowers really open but once. They may then shed no pollen 

 at all, they may shed pollen poorly, or they may shed pollen 

 freely and quite fully, depending on conditions of weather. 



The first anthesis of sets of flowers may be delayed from fore- 

 noon to afternoon (in A varieties) and from afternoon to the fol- 



