GRASSES OF IOWA. 



117 



fungi, for none of these organisms are truly parasitic. Much 

 of the corn during the season of 1897 showed a fairly good 

 percentage of germination, and yet the stand was very poor; 

 the seed in fact rotted in the ground . This was due to the con- 

 ditions above stated. Good germination requires warm weather, 

 with sufficient rain so as not to dry out the seed. 



CHEMICAL AND PHYSICAL. INFLUENCES ON THE GERMINATION 

 OF GRASS SEEDS. 



Chemical. — It has been customary for a long time to treat 

 wheat and other cereals with certain chemical substances for 

 the purpose of preventing fungus diseases. They have also 



^ Fig. 68. Copper compounds and the germination maize. U. S. Dept. of Agrl. for- 

 mula, 12, 13; o, Bordeaux mixture full strength ; 6, Bordeaux mixture one-half strength. 



