THE DEHISCENCE OF FRUITS 279 



pronounced in berries, much less evident in capsules, and 

 often more or less disguised, or very slight, in legumes. 



It is likely that the behaviour of the fruits of Scilla nutans 

 is typical of many capsules but partially filled by their seeds. 

 We will take the case of Stellaria Holostea. Here, as with Stellaria 

 fruits in general, the development of the fruit is far in advance 

 of the seeds. In its early stage, when about the size of a small 

 pea, the capsule is little more than an empty bladder, since the 

 young seeds do not occupy one-tenth part of the cavity. But 

 when the green fruit is full-grown, it is loosely but not entirely 

 filled by its soft white seeds, so that there is no pressure on the 

 capsular walls from within. Afterwards, as the fruit dries, the 

 seeds shrink and only half fill it. The valves, though still in 

 position, become disconnected at the edges, as a slight pressure 

 of the finger will show ; but there seems to be no reason why 

 they should be sundered in the drying process, since they 

 remain in position ; and it would appear probable that the 

 coherence between their edges was broken down, as in Scilla 

 nutans, when the biological connection of the fruit with the 

 parent first began to fail. 



Assuming that the first preparation for dehiscence is 

 accomplished when the capsule ceases active growth and begins 

 to mellow, then we perceive that the next cause of the actual 

 disconnection of the valves may vary according as the seeds 

 completely or only partially fill the cavity. In the first case, Thejdehis- 

 as with Iris, the capsular walls, owing to the loosening of the completely 

 connection between the valves, are no longer able to respond fi ]^j a jj cd 

 to the pressure of the seed-contents by increased growth, ripe capsules. 

 They yield at the weakened sutures and the fruit dehisces, the 

 valves as they wither and dry falling back and exposing the 

 seeds. On the other hand, when the capsule is not full of 

 seeds, so that there is no distension or pressure on the walls 

 from within, the cohesion between the valves is still loosened 

 in the mellowing stage, but they remain in position during the 

 early part or most of the drying. 



A few remarks may now be made on some other capsules. 



