3i8 



STUDIES IN SEEDS AND FRUITS 



The signifi- 

 cance of the 

 fact that in 

 thedrving 

 fniitSthe peri- 

 carp loses 

 far more 

 water than 

 the seed. 



And it is in 

 the behaviour 

 of the peri- 

 carp that 

 fruits differ 

 most. 



pericarp relation in the husky fruit of Barringtonia speciosa is 

 especially instructive. Here, as shown in the table in Note 

 1 1 of the Appendix, the pericarp proportion remains as high 

 as 98 or 99 per cent, until the fruit has attained to one-third 

 of the full size. When the fruit is half size, it is still as 

 much as 96 per cent., and after this falls to 82 per cent, in 

 the full-grown fruit, and to about 50 per cent, when the 

 fruit is lying completely dry on the ground. 



Much significance lies in the circumstance that as the fruit 

 dries on the plant the seeds form a larger proportion of the 

 weight of the entire fruit. When the moist fruit dries the peri- 

 carp loses far more water than the seed, the result being that 

 whilst the fruit-case dies the seed lives. If we were to strike 

 a rough average from the data given in the table on p. 320, and 

 more particularly from the results summarised for types at its 

 end, we would say that whilst seeds as a rule lose half their 

 weight during the drying process on the plant before entering the 

 rest-period, the pericarp loses generally from 70 to 85 per cent. 



It is, however, in the behaviour of the pericarp that fruits 

 differ most, the seeds as a rule presenting much less contrast 

 in this respect. Taking the averages below given, we find 

 that the pericarp sustains the greatest loss of 86 or 87 per 

 cent, in the case of typical fleshy or pulpy berries and typical 

 moist capsules, the living capsule being essentially a more or 

 less fleshy and watery fruit. The significance of this close 

 similarity in behaviour has been already dealt with in Chapter 

 XII ; but it is of interest here to note again that ripe fruits 

 seemingly so contrasted as those of the Apple, Gooseberry, 

 {Ribes), Prickly Pear {Opuntia\ on the one hand, and those 

 of Canna, Datura, Ipomosa, and Iris on the other, yield up 

 much the same amount of water as the fruit-case dries naturally 

 on the plant. Next come fleshy drupes, typically represented 

 by those of Prunus communis, which experience a loss of 75 

 per cent. Then we have the legumes with an average loss 

 of weight of 72 or 73 per cent. ; and last come the large woody 

 capsules, exemplified by those of the Mahogany tree, Ravenala, 



