THE DEHISCENCE OF FRUITS 287 



to leave alone. Nature, as we should read her story, is 

 indiiFerent to all. The distribution of seeds by dehiscing 

 fruits thus presents itself as determined by the laws con- 

 trolling the disintegration of dead organised matter ; and 

 in this disintegration the loss of the water necessary for 

 the fruit's vitahty occupies an early stage. It is with the 

 drying of fruits biologically severed from the parent plant 

 that the discharge of seeds by capsules, legumes, and other 

 similar fruits is usually connected. 



As previously pointed out, the typical dehiscence of Thedehis- 

 legumes occurs at or near the close of the drying process, legume is the 

 (The opening can be easily prevented by placing the fruit in a^j^dTrult?^ 

 wet moss, the valves ultimately falling apart'through the decay 

 of the connecting tissues.) If, then, dehiscence takes place in 

 a capsule in a living fruit, it takes place in a legume in a dead 

 fruit ; and all the objections urged in the case of a capsule 

 against regarding the propulsive liberation of seeds as a special 

 adaptation apply even more forcibly to the legume. Late 

 dehiscence is evidently characteristic of all those numerous 

 legumes, with which the reader will be familiar, where the dry 

 valves spring apart suddenly (throwing the seeds often some 

 distance) and then coil up spirally. It is likely, as in the 

 capsule, that the first loosening of the connection between the 

 valves takes place when the fully developed green legume 

 begins to soften or mellow, a stage marking the beginning of 

 the severing of the biological connection with the parent and 

 the ushering in of the drying process. But though such a 

 change is often more or less disguised in legumes, it may 

 be recognised at times in the paler green colour, and more 

 conspicuously in those cases where, as with Casalpinia 

 sepiaria, the green fruit assumes a yellowish tinge. The 

 drying pod generally darkens or blackens, as in Vicia, 

 Lathyrus, Ctesalpinia, Ulex, etc. ; but there are whole groups, 

 as with Canavalia, where the fruit as it dries becomes 

 lighter in colour and ultimately has a nondescript, parchment- 

 like appearance. 



