270 



PLANT DISEASES 



wheat head get on the mature grain at harvest time 

 and cling to the grain through the winter. They are 

 planted with the grain in the spring. When the grain 

 commences to sprout, the smut spore commences to 



FIG. 137. Spores of Fungi. 



I.sack with spores; 2, basidium and spores from a mushroom; 3, spore case of mold containing 

 numerous spores; 4, tuft of pinched-off spores of blue mold; 5, swimming spores of an 

 algal fungus; 6, spore of a black mold produced by a breeding act stalks of the breeding 

 cells are seen below the spore, i, 2, and 5, after DeBary; 3, after Sachs; 4 and 6, after 

 Brefeld. 



sprout and the hyphae, or threads, make their way to 

 the inside of the grain plant. They stay inside of the 

 plant and grow up with it until the wheat plant heads 

 out, when the parasite inside fills the kernels with its 

 threads ana then forms spores again. Now with a 

 knowledge of chis life history it can readily be seen that 



