THE IMPERMEABILITY OF SEEDS 



59 



All are variable or " mixed " in this respect. It would thus 

 appear from the results of the investigations of Dr Gola 

 that impermeability with the Leguminosae is not usually 

 a distinction between species, and hardly ever between 

 genera. 



But although the leguminous genera best represented in 

 the table of Dr Gola are " mixed " in the sense that not one 

 of them can be described as exclusively possessing species 

 with one type of seed, they may differ in degree considerably 

 from each other. The average proportions of permeable and 

 impermeable seeds for the species of the three genera. Acacia^ 

 Astragalus^ and Lathyrus^ are given below ; and from the 

 tabulated results it appears that in order of impermeability 

 Acacia stands first, with an average of 83 per cent, for a species, 

 and Lathyrus last, with an average of 20 per cent. 



Impermea- 

 bility not a 

 generic char- 

 acter, though 

 more charac- 

 teristic of 

 some genera 

 than of 

 others. 



Average Number of Permeable and Impermeable Seeds in the 

 Species of three Leguminous Genera. (Tabulated from data 

 given in Dr Gola's Memoir.) 



In the same way, with regard to species of Leguminosae, 

 it would seem that although as a rule, that is in 80 per cent. 

 of the plants, we cannot employ the presence or absence of 

 impermeability in the seeds as a specific distinction, yet species 

 differ very much in the proportion of impermeable seeds that 

 they possess. 



Such, then, are the preliminary conceptions with reference 

 to impermeability that one forms from the data obtained by 

 Dr Gola. These conceptions will be considerably extended 



