43 6 



BOTANICAL GAZETTE 



Lttjne 



laboratory, but in many cases no plants when sown in the field. 

 Unpublished data obtained by Eastham in Canada show that the 

 germination of oats grown in the prairie provinces is often seriously 

 reduced by early frosts. He says, "as far as our observations go, 

 a couple of degrees of frost in the milk stage are in many instances 

 sufficient to ruin oats for seed. In the dough stage they are not 

 nearly so susceptible, and when well ripened and dry stand con- 

 siderable frost without serious injury." Eastham found also 

 that such seed, germinating poorly when harvested, often improved 

 with age. This seems to indicate in such cases the necessity for 

 a period of after- ripening. Through the courtesy of the Canadian 

 seed laboratory and two American seed houses the author has had 

 the privilege of testing several samples of frosted oats. The 

 results are summarized in table VII. 



TABLE VII 



Germination of oats 



The best germination was obtained from hulled seeds in oxygen, 

 though the results are more clear-cut for no. 4948 than for no. 

 4920. No definite conclusions can be drawn as to what percent- 

 age of oxygen is most effective. It is noteworthy that two samples, 

 nos. 3477 and 4948, show much better germination, 23 and 27 per 

 cent respectively, than they did when tested in the Canadian Seed 

 Laboratory six months earlier. This agrees well with the state- 

 ment made above that frosted oats go through a process of after- 

 ripening and improve in viability as they grow older. There is the 

 same need of after-ripening in wild oats (Avena falua), as has been 



