260 STUDIES IN SEEDS AND FRUITS 



the dehiscent capsule and legume it is stated that when ripe 

 the pericarp usually splits into valves. One may note in 

 passing that this can only be said of the capsule. How- 

 ever, each of these statements taken independently has the 

 sanction of experience ; but it is an error to connect them 

 together in a classification of fruits, since they are essentially 

 incongruous. 



In the first place, as regards the two main divisions into 

 succulent and dry fruits, it is apparent that we are here con- 

 trasting moist fruits that have yet to dry with those that have 

 more or less completed the drying process. As already 

 indicated in Chapter XI, the moist fruit is a living fruit, 

 whilst the dry fruit is a dead one. Strictly speaking, 

 there is no such marked distinction in nature between moist 

 Nature does and dry fruits, except such as is connected with the differ- 

 sucha - 8 ^ 6 ence between a living and a dying or dead fruit. To be 

 distinction, convinced on this point we have only to look at the 

 columns of the following tables, though this view has 

 already been established in the previous chapter. Where, 

 for instance, are we to find amongst other types of fruits 

 the stage that is representative of the air-dried capsule of 

 Datura ? If we followed the method of the systematist 

 we should find it in the moist drupe of the Sloe (Prunus 

 communis). A glance at the tables will show that in so doing 

 we should be comparing a dead and dry fruit with a moist 

 and living one. Both the living capsule and the living drupe 

 in these two plants lose about the same amount of water 

 when they die and dry up (70 to 73 per cent, of their 

 weight) ; and if we contrast them we should either compare 

 them when they have attained their maximum size on the 

 plant as moist living fruits, or when they have lost their 

 vitality and have dried up. This is the only valid mode of 

 comparing fruits, and the failure to adopt it leads to erroneous 

 conceptions of the biological significance of the process of 

 dehiscence. The dried dehiscing capsule and the shrivelled 

 drupe go together. 



