38o STUDIES IN SEEDS AND FRUITS 



seeds of both varieties of the plant, the variety with mottled 

 black and pink or red resting seeds and that with pure white 

 resting seeds. The seeds of the last named are also white 

 when very small and undeveloped ; but they need not occupy 

 further attention here. 



The stages in the coloration of the variety with mottled 

 seeds are as follows. In their immature state, when very small 

 and soft, the seeds are pale green, with a pinkish or reddish 

 tinge, the embryo being darker green. As the seeds increase 

 in size they become uniformly pink or reddish, the embryo 

 becoming paler in hue. When the seed approaches maturity 

 as a pre-resting seed the pink colour of the coats deepens, 

 and dark mottling begins when the soft full-grown seed 

 commences to harden its coverings. (It may be noticed in 

 passing that the soft, pink pre-resting seed parts with most of 

 its colour when placed in water. This helps to explain the 

 partial blanching which the half-sized pink seeds sometimes 

 experience in the green pod, a change which has a bearing on 

 the deprivation of colour in the white seeds of the other 

 variety.) 



During these observations and experiments on the seeds of 

 Phaseolus multiflorus some indications pointed to the probability 

 that the black mottling and hardening of the coverings were 

 independent of the drying of the pod, though usually associated 

 with it. Other signs seemed to show that the mottling only 

 became at all evident after the pod had begun to dry. How- 

 ever, the point whether the preliminary drying of the pod was 

 really necessary, or was merely an accidental association, was 

 unexpectedly decided by an experiment begun with quite 

 another object. Some fresh green pods containing only the 

 large, soft, pink seeds, showing scarcely any black mottling, 

 were kept in wet moss in a closed tin for nine days with the 

 purpose of inducing the seeds to germinate without entering 

 the shrinking stage. However, although no seeds were ger- 

 minating, all of them, when the tin was opened, had hardened 

 normally mottled coats. The pods themselves were com- 



