36 



STUDIES IN SEEDS AND FRUITS 



a number of seeds together. Only the very large seeds 

 were treated individually ; and I here give the shrinking 

 ratios for three full-sized pre-resting seeds of Entada scandens 

 (all of which subsequently germinated), the weight of the 

 resting seed being taken as i. They were 2*46, 2*51, 

 and 2*62. 



My method of determining the swelling ratios was better 

 fitted for ascertaining their range in seeds of the same species, 

 and the sample of results given in the tabic below is sufficient 

 to bring out their relative constancy. 



The great 

 contrast 

 between the 

 shrinking 

 and swelling 

 ratios in 

 different 

 species. 



Species. 



Adenanthera pavonina . 



Cassia grandis 



Entada scandens 



Faba vulgaris (Broad Bean) 



Guilandina bonducella . 



Mucuna urens 



Poinciana regia 



Canna indica . 



Family. 



Leguminosce 



Cannacece 



Number 

 of seeds 

 tested. 



Range of 



the swelling 



ratios. 



2*30 

 2*04 



2 '2 I 



I '95 



2-8o 



1-93 



2-34 



I '43 



2 '60 



2*22 



2-59 



2 -08 



3'26 



2'12 



2 '44 



1-52 



Average 

 ratio. 



2-42 

 2-13 

 2-42 

 2 'ox 



3-08 

 2-05 

 2-32 



The next point to notice is the great contrast which the 

 seeds of different plants display in their combined shrink- 

 ing and swelling capacity. Relatively to their weight some 

 seeds shrink and swell three or four times as much as 

 others. We have seen that as a general rule the water lost 

 in the shrinking is regained in the swelling, the one counter- 

 balancing the other, so that it would be legitimate to 

 estimate the missing ratio where only one value has been 

 found. It will, however, be more convenient at first in 

 dealing with the great range of the capacities to speak only 

 of the swelling ratio, remembering of course its reciprocal 

 character. 



In the tables the swelling capacity is stated as a ratio of 

 the weight of the resting seed taken as i, the reason being 

 that the swelling is only one-half of a reciprocal process which 

 is centred in the resting seed. To avoid, therefore, the in- 



