1915] ROSE—DELAYED GERMINATION 435 
this water was supplied, by long soaking or by forcible injection 
under pressure, germination was much improved. 
Results for Pinus austriaca are less conclusive on this point. 
They do show, however, and the same is true for P. Strobus, that 
soaking in either water or weak acid gave greater germination than 
was obtained in the controls, 38 per cent and 13 per cent respec- 
tively. For P. austriaca, better results were obtained from short 
than from long soaking. 
Referring again to table IV, it is possible that the increases in 
germination shown there were due not so much to the cold storage 
in itself as to the thorough infiltration of the seeds with water. 
There is need of much more work on this question before any 
definite conclusions can be drawn. 
Exclusion of oxygen 
No attempt will be made to review former work, since this 
has already been done by SHuLt (28). Results presented in table 
VI seem to indicate that the germination of certain economic 
seeds is delayed for lack of oxygen. They also indicate the need 
of a detailed study of these seeds. 
TABLE VI 
GERMINATION OF SEEDS TREATED WITH OXYGEN OR HYDROGEN PEROXIDE 
Kind of seed roi ong ee Vatieated In 80 eo it cent | Ino. 15 vs cent 
| 
Pieeling 25. tee 14 AOA aes ey 72 
Datura— | 
Golden een aun Semmes 14 Be ee ees 70 
Selig tlt NRT ree T4 Mr eee aa cae 100 
hin ati 
Grand Rapids.......... 10 ° 44 32 
POMS 20 ° go 80 
Datura Wrightii was forced considerably by hydrogen peroxide, 
Datura Golden Queen not at all. Lettuce gave good results, but, 
as has been suggested, this is probably due to absorption of water. 
Effect of frost on seeds 
ATTERBERG (2) says that seeds of oats and barley harvested 
in Sweden after a heavy frost gave fair to good germination in the 
