72 



STUDIES IN SEEDS AND FRUITS 



different nature. A sample of the bared kernels weighing 

 lOO grains immediately after the removal of their shells 

 will be found after a period of four or five days to have 

 increased its weight to iii or 112 grains. The gain in 

 weight begins as soon as the hard coats are removed ; and 

 thus my materials became sensibly heavier whilst in prepara- 

 tion for the balance. In one case, for instance, a sample 

 of 500 grains weighed 503 grains after an hour occupied 

 in preparing it for an experiment. This increase in weight 

 is maintained, although in a diminished degree, for a long 

 period. In fact, the bared kernel never returns to the 

 weight it possessed when enclosed in its impermeable cover- 

 ings. As is shown in the table below, after a period of a 

 year and more, it is still 3 or 4 per cent, in excess of its 

 original weight. 



Results of the Exposure to Air of the bared Kernels of 



GUILANDINA BONDUCELLA. (WeIGHT IN GRAINS OF SIX KERNELS 



AT VARIOUS Periods.) 



The explanation, of course, is simple. The kernel when 

 bared, being in a state of ultra-dryness, supplies its deficiency 

 by absorbing water from the air. In so doing it has changed 

 its nature and now responds to the hygrometric variations 

 of the weather, behaving in fact like the kernel of a permeable 

 seed. We have here, then, the disclosure of another striking 

 character distinguishing impermeable seeds, such as those of 

 Guilandina bonducella^ from permeable seeds, like those of 

 Canavalia ensiformis. 



This curious quaHty has been exhibited in varying degrees 



