278 



STUDIES IN SEEDS AND FRUITS 



Scilla 

 nutans. 



The normal 

 dehiscence of 

 an actively 

 growingfrait 

 impossible 

 for physio- 

 logical 

 reasons. 



TABLE SHOWING THE Loss OF WEIGHT WHEN DRIED IN AIR OF FULL- 

 SIZED, MOIST, CAPSULAR FRUITS, BOTH BEFORE DEHISCENCE AND 

 IN THE EARLIEST STAGE OF DEHISCENCE, THE DEHISCING FRUITS 

 BEING GATHERED IN THAT CONDITION FROM THE PLANT. 



Note. The average was taken of from five to ten fruits in each case. 



But it is often very difficult, by observing capsular fruits 

 on the plant, to eliminate the drying factor ; and the most we 

 can often say in such cases is that dehiscence takes place in 

 the living fruit before the drying is very evident. In the case 

 of Scilla nutans , for instance, we find the full-grown green 

 capsule in a condition of strain, not, however, on account of 

 the pressure of the enclosed seeds, since they only partly fill 

 the cells, but through the turgidity produced by active growth. 

 Though green and moist, it ruptures with a " pop " when 

 squeezed between the fingers. A little later the fruit becomes 

 paler, looks a little dryer, and its turgid appearance has dis- 

 appeared. If we press it gently, there is no longer an elastic 

 resistance, and the valves, though still in position, are seen to 

 be partially disconnected. The fruit has dehisced, although 

 still green and fairly moist, and only the pressure of the finger 

 reveals what has occurred. Here it seems impossible to 

 separate the dehiscence from the early stage of drying ; and 

 yet the loosening of the cohesion between the valves was 

 probably effected in the mellowing stage when the firm, turgid 

 green fruit became softer and almost flaccid. On physio- 

 logical grounds I would suppose that the dehiscence of a green 

 fruit in active vitality could never be normally produced either 

 by internal or external causes, and that dehiscence could only 

 occur after the biological connection with the parent begins to 

 be severed. This I take to be the mellowing stage of fruits, 



