492 



STUDIES IN SEEDS AND FRUITS 



per cent, to its weight, and in Ricinus a little over 40 per cent. But 

 the relatively small amount of w^ater absorbed by the kernel of a seed 

 of Hura crepitans^ when swelling for germination, is counterbalanced 

 by the large amount taken up by the coverings, which increase their 

 weight threefold, as already illustrated in the first table of this note 

 (see also p. 212). In spite of this great absorption, however, the coats 

 do not attain their original weight in the pre-resting seed, whilst the 

 kernel exceeds it. Though the contrast in behaviour is here much 

 exaggerated, it exemplifies a principle in operation in many seeds, as 

 discussed in Chapter IX. 



Table Illustrating the Changes in Weight and in the Proportion 

 OF Parts in the Case of Seeds of Hura crepitans after they 

 HAVE Attained the Maximum Weight and Size in the Pre-resting 

 State. 



( W = weight in grains ; P = percentage. ) 



A shows the progressive stages in the weight and proportions of the coats and kernel, 

 beginning with the later maturing stages, when the pre-resting seed has attained its 

 maximum weight and size, and going on to the resting state and to the swollen state 

 immediately preceding germination. 



B shows the changes in the weight and proportions of the albumen and embryo in 

 the later stages of the maturation of the pre-resting seed, and also the changes in the 

 resting seed and in the seed swollen for germination. 



C shows that the shrinkage of the coats in the later stages of maturation is restricted 

 to the inner crustaceous shell, which hardens as the process advances. 



Note that the data given in column V. refer to the pre-resting seed when the kernel 

 (albumen and embryo) has reached maturity. They are the data used in the table on 

 p. 219. 



