NATION 



from mature seeds, with intermediate stages at intervals of one day. The dry matter in a barley seed six days 

 more slender than those from mature seeds, develop normally and produce seed. (Fig. 16.) 



In the six-rowed varieties the flowers of 

 the central rows are polHnated before 

 those of the lateral rows. 



In four of the varieties the first 

 samples were taken six days after 

 flowering. In one variety the first 

 sample was taken seven days, in a 

 second, eight days, and in a third, nine 

 days after flowering. These samples 

 were taken by cutting the culms and 

 placing the spikes in paper envelopes. 

 The seeds were not taken from the 

 spikes until the following winter when 

 the germination was tested by sowing 

 the seeds in flats in the greenhouse at 

 Arlington Farm, Virginia. The seeds 

 were placed in rows spaced at definite 

 distances and covered lightly with soil. 



When the experiment was planned in 

 1920 it was thought that germination 

 would first occur in seeds which had 

 developed for about 14 days. In 

 mature seed the embryo is provided 

 with an epithelial layer which secretes 

 the diastase necessary for the digestion 

 of the starch endosperm. The epithe- 

 lial layer is not fully formed until about 



the 14th day after the flower is ferti- 

 lized. There are several other changes 

 that take place at this time which indi- 

 cate approaching maturity. A second- 

 ary stage of starch formation com- 

 mences. The peak of the water content 

 of the kernel is reached at this time. 



It is readily seen in the table that the 

 hypothesis of time of germination was 

 not correct. It was thought that all 

 samples were taken sufficiently early to 

 show the inception and gradual in- 

 crease in percentage of germination. 

 All of the varieties showed germination 

 at six days from flowering. The Baku 

 variety gave a perfect percentage of 

 germination at that age. It may be 

 possible that the Gatami shows the 

 progress that should be expected. On 

 the 6th day after flowering four of the 

 seven central kernels germinated while 

 only three of the seven lateral ones 

 germinated. On the 7th day all of the 

 central kernels were viable while only 

 six of the seven lateral ones grew. It 

 was not until the 8th day after the 

 spikes were recorded as flowering that 



