212 Maine Agricultural Experiment Station. 1920. 



extent. On comparing Table 2 with Table 1 it will be seen that 

 the stunting and dying off of the radicle within the glume is 

 likewise occasioned by the artificial conditions prevailing in the 

 germinator, and hardly occurs in the soil. 



Before discussing briefly the causes of abnormal germina- 

 tion attention should be called to the fact that if a growing 

 organism is to effect a certain performance it is essential that it 

 be sufficiently anchored to prevent its being pushed back or bent 

 aside. If this is not the case the organ will grow in the direction 

 of least resistance. 



Another point to be emphasized is that normally it is the 

 coleorhiza that breaks through the tissues of the lemma. If the 

 coleorhiza fails in this important function the conditions for ab- 

 normal germination are fulfilled. 



Considering the most frequently occurring form of abnor- 

 mal germination, where the lemma is bent from the caryopsis, 

 it is obvious that here the pressure of the extending coleorhiza 

 does not reach the intensity required to break through the base 

 of the lemma. It does, however, reach an intensity sufficient to 

 bend the lemma away from the caryopsis. The coleorhiza thus 

 effects a performance in the direction of lesser resistance and 

 the radicle, after escaping from the coleorhiza, is unable to pene- 

 trate the lemma and grows along the inner surface of the latter. 



The same mechanical cause, though attended by a different 

 external effect, brings about the other irregularities of abnormal 

 germination. In those cases where the caryopsis is raised in the 

 glumes the effort of the extending coleorhiza to break through 

 the lemma is annulled by the caryopsis receding under pressure 

 from the base of the lemma. The radicle upon leaving the col- 

 eorhiza may in turn raise the caryopsis somewhat and then bend 

 upwards and appear at the tip of the glumes, or it may remain 

 with its apex at the base of the glumes and push the caryopsis 

 out and away sometimes for several centimeters from the 

 glumes. 



The degree of adhesion of the glumes to the caryopsis de- 

 termines the kind of abnormal germination and is in turn in- 

 fluenced by the amount of moisture available in the germinator. 



A quite distinct form of abnormal germination is shown by 

 Oryza sativa. In a majority of examined seedlings it was found 

 that the first signs of growth at germination are shown by the 



