116 



GRASSES OF IOWA, 



known as a stolon. The old name for the fungus, Mucor sto- 

 lonifer, was given to it because of the production of these sto- 

 lons. In addition to the formation of spores in the sporangium, 

 zygospores are produced in certain races. Two threads of the 

 mycelium lying in proximity and nearly parallel, each pro- 

 duces a tube. These meet, the walls are absorbed, and just 

 back from the meeting point a cell is cut off. The contents 

 from the old cells pass into the newly formed cell. We also 

 observe that the cell of one arm is somewhat smaller than the 

 other. This spore is a resting spore or zygospore. It lies 

 dormant for a period, then germinates by forming directly a 

 conidiophore with its sporangium containing the spores. 



Bacteria. — In an examination of mouldy corn, bacteria have 

 been found in large quantities, but none of these have been 

 studied sufficiently to speak of the power they have in causing 

 rot. Prillieux* states that wheat is often covered with a bac- 

 terial organism that produces a red coloration. Not enough, 

 however, is known of this organism to say whether it is the 

 cause of the disease mentioned by him or not. 



The first step in the germination of corn, as said before, is 

 the absorption of water. If the embryo is vigorous, and con- 

 ditions are favorable, the young embryo will push through the 

 testa and pericarp. 



Fig. 65. Mouldy maize kernels. These failed to germinate, i, Sterlgmatocystis; 

 2, Apergillus; 3, Rhizopus; 4, Penlcillium. 



On the other hand, if it is weak it is unable to do so. A 

 cold, damp soil and frequent rains are not favorable for the 

 embryo to push through, and hence the invasion of saprophytic 



*Prlllieiix. AnnaldeSci. Nat. Bot. VI. 7: 248. 



