CHAPTER XIII 



THE DEHISCENCE OF FRUITS 



One is apt to associate the process of dehiscence with dryish 

 fruits, neither very soft nor very hard, and justly so, because 

 many opening fruits belong to this category. Both the capsule The capsule 

 and the legume are classed amongst dry fruits ; and the beforrdry- 

 implication often is that their dehiscence is connected with 1"^^^"^^*^ 

 the relief of strain produced by unequal contraction during drying, 

 the drying of the fruit. My observations indicate that this 

 applies more especially to fruits like legumes, that often only 

 dehisce after they have been considerably dried, and that as a 

 rule it does not concern capsules. The incorrect conception 

 seems to be due in the case of capsules to the tendency to 

 regard as one and the same process the loosening of the cohesion 

 between the valves or carpels, which may take place when the 

 green fruit begins to mellow, and their subsequent drying, 

 when the fruit is rapidly losing its vitality. The sudden relief 

 of tensions generated by drying in the latter part of the dehis- 

 cence, resulting as it sometimes does in the forcible expulsion 

 of the seeds, produces effects that often emphasise the influence 

 of drying in the latter stages of the process, and is apt to favour 

 the idea that dehiscence is merely a matter of desiccation. 



Thus, in Fiola, the breaking down of the cohesion between capsules 

 the valves is one thing, whilst the subsequent folding inwards „nder*^mfist 



of the edges as the valve dries up is another. Whether the conditions 



where drv"" 

 "nipping" and forcible propulsion of the seeds are purposive ingispre- 



or merely accidental can only be determined after an extensive 



273 18 



