1918] Kendall: Abscission of Flowprs and Frnifs in Sola'naceae 407 



8. Fertilization has no intluenee whatever in preventing abscission 

 when the latter is induced by a transverse cut completely through tlie 

 flower at the base or middle of the cah'x (table 3, c and d). 



9. Certain types of injury, such as entire removal of the calyx and 

 stamens or removal of the entire calyx and half the corolla, evidently 

 cause abscission only by preventing fertilization (table 3, a and h). 



Taking up now the results given in table 4. which dealt with 

 Fj H179. it will be seen that this hybrid is more sensitive to injury 

 than is N. Langsdorffli. Nevertheless, it is very plain that the general 

 conclusions announced above for this latter species hold for F^ H179 

 also. There follows a partial summary of the results in table 4 and 

 a comparison of these results with those obtained in the experiments 

 on N. Langsdorffli. 



1. It seems that removal of the calyx causes fall of much larger 

 buds than in X. Langsdorffli (table 4, d). 



2. F^ H179 is evidently much more sensitive in its abscission re- 

 action to a transverse cut through the flower at the middle of the calyx 

 than N. Langsdorffli (table 4, a). 



3. It would seem that slitting the calyx and corolla even to the 

 extent of dividing these organs into four longitudinal strips does not, 

 as a general rule, cause abscission. Such an injury does cause abscis- 

 sion only in extremely small buds (table 4. gr). 



4. It appears that puncturing the calyx, corolla and ovary so 

 that a hole is formed about 2 ram. in diameter in the latter organ 

 causes fall in flowers of all sizes up to two or three days past anthesis 

 (table 4. h) . Since it is evident that such a hole through the calyx 

 and corolla alone would not cause abscission (table 4, ^). abscission 

 in this case must be induced by injury to the ovary. 



5. It is evident that a slit completely through the pedicel for its 

 entire length fails to cause fall in buds or open flowers, but where an 

 effort is made to destroy completely the connection between the flower 

 and stem abscission will occur (table 4, i). 



(i. Removal of the style or stamens, as a general rule, causes fall 

 only in young buds, but removal of the former organ is probably more 

 eft'ective in causing flower-fall than removal of the stamens (table 4. e 

 and /). On the other hand, where half the corolla is removed along 

 with the stamens fall occurs in larger buds than where only the latter 

 organs are removed (table 4, ?>). 



7. Removal of only half the corolla apparently does not induce 

 abscission (table 4, c). 



