8o STUDIES IN SEEDS AND FRUITS 



That the absorptive capacity of the impermeable seed, that 

 is to say, its power of absorbing water from the air in the 

 broken condition, varies inversely with the water-contents was 

 implied a few pages back. A small water-percentage and a 

 large absorptive capacity go together, and vice versa. This is 

 brought out in the tabulated results given below for Guilandina 

 honducella. These experiments were carried out in different 

 places and under varying hygrometric conditions, so that only 

 a general result is to be expected. Better examples of the 

 principle that the impermeable seed when broken up takes up 

 water from the air in proportion to its ultra-dryness are given 

 in Chapter VI. 



The be- 

 haviour of 

 the perme- 

 able seed 

 under the 

 oven test. 



Results of three Experiments on the Seeds of Guilandina 



BONDUCELLA, SHOWING THAT WITH IMPERMEABLE SeEDS THE SeED 

 WHICH ADDS MOST TO ITS WEIGHT IN THE BROKEN CONDITION 

 BY ABSORBING WaTER-VAPOUR FROM THE AlR IS THE SeED WITH 



THE SMALLEST Water-contents. (Stated in percentages, the samples 

 varying between 50 and 130 grains.) 



When we contrast the behaviour under the oven test of a 

 permeable and an impermeable seed we obtain very different 

 results. The seed of Canavalia ensiformis, after being subjected 

 to the same oven test in the broken state, regains in a few 

 days most of its lost water from the air ; and after a week or 

 two reaches its original weight affected only by the ordinary 

 hygroscopic variation of 2 or 3 per cent. For example, a 

 sample of seeds weighing 100 grains would be reduced in the 

 oven to about 85 grains. After standing for four or five days 

 its weight would be about 98 grains, and in a few more days 

 it would attain its original weight, varying according to the 



