118 



GRASSES OF IOWA. 



been treated for other purposes. These purposes may be 

 classified as follows; First, to hasten germination; second, to 

 protect the seed from insect and other animal pests; third, to 

 prevent the attacks of iMugi; fourth, to furnish the young plants 

 nourishment. It is very doubtful indeed if any kind of treat- 

 ment with chemicals actually hastens the germination of seeds. 

 Formerly a large class of substances were given which would 

 support and hasten germination. The literature on this sub- 

 ject as given by Nobbe* states that the seeds of certain crucifers 

 when in contact with chlorine germinated in from six to seven 

 hours, while seeds placed in water germinated in thirty-six to 



Fig. 67. Copper compounds and the germination of maize. U. S. Dept. of Agrl. 

 formula. 3, 4, treated with ammonlacal carbonate of copper normal;!. 2, double 

 normal. 



•Samenkunde. 255. 



