DIMORPHISM IN CONIOTHYRIUM PIRINUM SHELDON 463 
I. Small pieces of agar containing plus and minus mycelium 
respectively were placed side by side on starch agar. In the resulting 
Fig. 14. Culture of a minus strain with the same enlargement as Fig. 13. 
The mycelium is dark throughout the greater part of the culture. The pycnidia 
are few, large, producing shining black masses of spores. The greenish color has 
been removed from the mycelium immediately surrounding the pycnidia. Some 
white fluffy aerial mycelium is present on the surface. 
growth the two sectors were entirely distinct and typical. The minus 
portion was in all cases much larger than the plus portion. 
2. Spores of plus and minus strains were mixed and then used to 
