THE THREE CONDITIONS OF THE SEED 37 



convenience of stating the values of the shrinking and 

 swelling in different terms, a simple reciprocal ratio was 

 invented, as described in a previous page. Thus, to take the 

 seeds of Canna indica^ where the pre-resting seed loses 66 

 per cent, of its weight in entering the resting stage, and where 

 the resting seed adds 50 per cent, to its weight in swelling for 

 germination, the use of percentages for the two results would 

 be clumsy and inconvenient. But stated in this manner : 



Pre-resting seed. Resting seed. Swelling seed. 



1-5 i-o 1-5 



we at once get a clear view of the problem. 



Now, however, when we are dealing particularly with the The employ- 

 swelling capacity, the usual method of stating the increase as centages in 

 a percentage of the weight of the resting seed will be adopted. ^th"he°'^^^ 

 The conversion of the ratio into a percentage is simple enough, swelling 

 the swelling ratio of 1-5 for the seeds of Canna indica being 

 equivalent to an increase of weight of 50 per cent. We see 

 accordingly that with many Leguminosae, where the seed 

 swollen for germination is more than double the weight of 

 the resting seed, the increase amounts to more than 100 per 

 cent. Thus with Abrus precatorius^ where the swelling ratio, 

 taking the resting seed as i, is 2*05, the actual increase in 

 weight is 105 per cent. 



Looking at the extremes of the range of the swelling The range of 

 capacity of seeds in general, we find amongst the hundred capacity/^ 

 and odd plants in the tables two groups that we can handle ^^ ^I^aX 

 fairly well, one where the absorbing capacity is not over extreme 

 60 per cent., the other where it is at least twice as much, ' 



reaching 120 per cent, and over. In the first or "minimum " 

 group are to be included a number of plants in Table B, 

 such as all the Cereals, species of the cruciferous genera 

 Brasska and Camelina, Cannabis sativa, Pinus austriaca, and 

 one or two others, together with several in Table A of the 

 genera Anona, Canna, Citrus, Datura, Ricinus, Theobroma (Cacao), 

 etc., belonging in both cases to a variety of families, but, 



