19 14] CROCKER & DAVIS— DELAYED GERMINATION 287 



always freed from this structure, leaving only the seed proper. A 

 single harvest of seeds thus prepared shows much variation between 

 the individuals both in appearance and in physiological behavior. 

 Iii color the seeds vary from a deep reddish brown to a light pink. 

 As a general rule the intact dark seeds absorb water less rapidly 

 and to much slighter total amount than the light-colored ones. 

 With the coats broken or removed, they also show far less vigor 

 in water absorption and in growth rate. For this reason, in the 

 experiments here reported, light-colored seeds of plump appearance 

 were selected chiefly. Even with this precaution to remove less 

 vigorous ones, the seeds showed great variation in rate of water 

 absorption and of growth. 



The large 



The air-dry seeds freed from the pericarp retain a 

 large percentage of water. The amount approximates 1 

 varying with the humidity of the air and with the seed, 

 percentage of water retained in contrast to many fatty seeds is 

 probably related to the richness of the embryo in starch and of its 

 walls in pectic substances, and to the high pectic content of the 

 relatively thick coat. 



When seeds were to be used with coats broken or partly removed, 

 it was at first done by inserting a thin knife blade between the two 



mbryo. This me 



many coats i 

 embryo from 



It also often 



embryos at the arch. It was soon found that slight 



m 



em 



>ryo. The break 

 occurs at thin regions well shown in fig. 1. In some experiments, 

 the coats were also removed by similar means from the end of the 

 embryo adjacent to the micropyle. In this case the breaking was 



more irregular, and the size of the pieces showed more 

 although at this end of the embrvo the coat shows very 



definit 



case at the micropyle end. The feature just described also accounts 

 for the method by which the embryo breaks the coat after the seed 

 is treated with an acid or a base. In this case the same sort of 

 cap is pushed off the micropyle end of the coat by the lengthening 



