THE THREE CONDITIONS OF THE SEED 51 



Sometimes these deviations from the normal behaviour of 

 a seed become fixed ; and Nature then facilitates our inquiries 

 by presenting in the same species two types of seeds which are 

 distinguished not only in size and colour, but also by their 

 different degrees of impermeability. Such seeds have also 

 two corresponding degrees of swelling capacity, the permeable 

 seeds requiring much less water than the impermeable seeds. 

 Entada polystachya, as observed by me in Grenada, is a case of 

 this kind. Here we find two types of seeds differing from 

 each other in almost all the critical points that distinguish 

 permeable and impermeable seeds, and equally capable of 

 reproducing the plant. As indicated in the table below, they 

 differ in colour, size, and weight, as well as in their swelling 

 capacity, the permeable seed increasing its weight by about 

 124 per cent, before germination, whilst the impermeable seed 

 requires more water and adds 1 50 per cent, to its weight. 



COMPARISON OF THE TWO TYPES OF SEEDS PRODUCED BY 

 ENTADA POLYSTACHYA 



(c) Entada 

 polystachya, 

 which dis- 

 plays the 

 same prin- 

 ciple in its 

 two types of 

 seeds. 



Different hypotheses present themselves in explanation of 

 this relation between the swelling capacity and the permeability 

 of a seed. For example, it may be suggested that it is merely 

 a matter concerned with the water-contents or hydratation of a 

 ,seed, a view that would accept, without explaining, the impli- The question 

 cation of these experiments, that impermeable seeds contain ^ 

 less water than permeable seeds. To form an opinion 

 would be to prejudge a matter which will prove to be far more way. 



now permeability 

 UW blocks the 



