1918] Kendall: Abscission of Flowers and Fruits in Solcmaceae 393 



allowance must be made for the approximate number of days preced- 

 ing anthesis. Thus, if a flower of the above species is injured three 

 days before anthesis, tbe fall can not be assigned to the injury unless 

 it occurs before ten days have elapsed. The minimum time for 

 F 1 H179 is about five days; thus, any time of five days or more recorded 

 on a flower, injured near anthesis, was considered as "no fall." The 

 minimum time for Lycopcrsicum is about six days. 



Finally, it is necessary to state that the process of reaction to the 

 different types of injury recorded in the following tables was by no 

 means impeded by low temperatures. Xicotiana Langsdorffii was 

 tested out in a greenhouse where the average temperature approxi- 

 mated 75° F. The tests on F 1 H179 and Lycopcrsicum were per- 

 formed in the botanical garden of the University during July and 

 August, when the temperature was also comparatively high. 



The following statement of results is derived in great part but not 

 entirely from the foregoing tables. It has been noticed that cutting 

 off the freshly opened flower at the tip of the pedicel causes the 

 remainder of the pedicel to be thrown off >n from ten to fifteen hours, 

 but after the same operation on developed capsules the pedicel re- 

 mains firm from thirty-six to ninety-six hours after the injury. 

 Removal of the calyx causes the fall of buds in two or three days, 

 depending upon the age of the bud. Removal of half the calyx 

 together with two-thirds of the corolla and all the stamens causes 

 fall in one to four days, depending upon the age of the flower. A 



TABLE 3 



Effect of Pollination of Flowers of N. Langsdorffii var. grandiflora on 



Reaction to Injury 



No. 







Avg. No. 



flowers 



Pollination 



Injury 



days before 









fall 



/ 2 

 a { 2 



pollinated when injured 



calyx and stamens cut 



no fall 



not pollinated 



t ( 



10 



'{1 



pollinated when injured 



calyx " i corolla cut 



no fall 



not pollinated 



1 1 



8 





No. days after pollination when 









injured 







r 2 



1 



all organs cut at tip of pedicel 



2 



1 2 



2-6 



i t 



o 



e-j 2 



7-8 



t c 



2 



1 3 



2 



i calyx, s corolla, stamens, 



4 



L 





style cut 





r 3 



4-5 



t t 



5 



1 o 



"ii 



6-7 



1 1 



2 



fi 



i t 



3 



!> 



i < 



no fall 



