THE HOMOLOGIES OF FRUITS 261 



The same rule applies when we look for the representative 

 of the Datura capsule amongst the legumes or the berries. 

 A Canavalia pod, an Arum berry, and a Datura capsule 

 contain about the same amount of water in the fuU-orown 

 living state, and can only be compared in the same condition 

 either as moist living fruits or as dry dead ones. We thus 

 come to perceive that all fruits, when they reach maturity 

 on the plant, whether drupes, legumes, berries, capsules, All mature 

 etc., are moist fruits and cannot be distinguished from each are'moiS^*^ 

 other by their water-contents. Nature does not recognise ^'■"**s- 

 the distinction between moist drupes and berries on the 

 one hand and dry legumes and capsules on the other. 

 Group for group, the contrast between capsules, legumes, 

 berries, drupes, etc., as regards their water-contents in the 

 full-grown living condition, is relatively small ; and in 

 each group we find much the same variation in the amount 

 of water lost in drying, namely, between 50 and 80 or 85 

 per cent. 



The differences are mainly developed when we allow the 

 drying to take place in all cases, the berry and the drupe to 

 shrivel up, and the capsule and the legume to dry and dehisce, 

 the ultimate contrast between the asymmetry of the one kind 

 and the retention of the regular form in the other being 

 dependent on the nature of the tissues composing the pericarp. 

 Nature makes no deliberate effort to assist the systematist, 

 and inconsistencies of the kind above noted are inseparable 

 from our necessarily arbitrary endeavours to systematise her 

 processes. The error involved above is of course the com- 

 parison of fruits that are not in the same stage. But other 

 inconsistencies are apt to follow. Thus, as already noticed, it 

 is implied in the above statements from The Handbook of the 

 British Flora^ that dry dehiscent fruits like those of the capsule 

 and the pod open when they are " ripe." This might indicate 

 that dehiscence occurs in these fruits in the moist, mature 

 condition. But, as we will see in Chapter XIII, this is 

 only true of the capsule, the legume opening when the fruit 



