THE REST-PERIOD OF SEEDS 423 



and the rest-period begins. In other words, the fruit dies and 

 the seed lives, or rather it retains the potentialities of life. In 

 Chapter XIII I have dealt with the difFei-ent behaviours of 

 the legume and the capsule as regards dehiscence, the first 

 dehiscing after drying is nearly or quite complete, the second 

 before drying commences or in its earliest stage. As the result 

 of these changes, the seeds shrink and harden rapidly when 

 exposed in the drying, dehiscing capsule, and less rapidly, but 

 not less effectually, in the drying but still closed pod. 



If it were not for the drying of the fruit there would be 

 no reason why the soft seeds in the moist living fruit should 

 not proceed continuously with their development and dispense 

 with the rest-period altogether. In theory this should be 

 brought about by preventing the drying of the fruit. In 

 practice actual experiment has shown that this can be arranged, 

 as I have done with different fruits of Vicia, Arenaria, QuercuSy 

 and Iris, by placing the fruit in moist, warm conditions when 

 in the full-grown living state. Under such circumstances the 

 capsular valves separate, whilst the legume decays rather than 

 dehisces, and the seeds will be found germinating In a week or 

 two without having experienced any pronounced check in the 

 development of the embryo. 



But these are not the conditions usually presented in 

 nature. The capsule dehisces and dries, whilst the legume 

 dries and dehisces ; and the further development of the 

 embryo is arrested by the resulting shrinking and hardening 

 of the seed. On the assumption that the continuous growth 

 of the embryo-plant is the primal normal condition, there is 

 an obvious lack of co-operation or co-ordination here, since 

 experiment is able to arrange for the working together of the 

 conditions so as to ensure the uninterrupted growth of the 

 embryo. There is a lack of co-ordination in the capsule, 

 because the seeds are exposed in the moist fruit before the 

 embryos can lead an independent existence. There is a lack 

 of co-operation in the legume, because the pod begins to dry 

 before the seeds can sprout. 



