STINKING SMUT OF WHEAT 



219 



are capable of entering the tissues of a very young wheat 

 plant. 



Fig. 52. Tilletia iritici. i, ear of wheat 

 diseased ; 2, spore, x 300 ; 3, 4, spores ger- 

 minating and producing a germ-tube bearing a 

 cluster of secondary spores at the tip, x 300 ; 5, 

 two secondary spores that have conjugated or 

 become united by a short, transverse neck ; one 

 of the secondary spores has produced a coni- 

 dium, x 300 (3-5 after Brefeld). 



The secondary spores produced in the air germinate 

 readily in a nutritive solution as saprophytes, forming a 



