46o 
C. H. CRABILL 
no doubt also exhibit this change and a sector unlike the rest of the 
plant would be the result. 
Similarly with a colony. Different spores might give rise to 
hyphae unlike in their growth characters and sectoring of the colony 
Fig. II. 24 days old cultures of minus and plus strains of II and III for com- 
parison. II — is in the nth generation. II + is in the 3d generation after the 
splitting off of the third minus strain. Ill — is in the 4th generation. Ill + is in 
the 5th generation and shows the small minus sector which gave rise to the 2d minus 
strain from III. The cultural characters of the two minus and the two plus cultures 
are identical. In the minus cultures it will be noticed that some sectors produce 
more pycnidia and more color than others. This fact was taken advantage of in 
trying to develop a plus strain from a minus strain by selection. 
would result. In the present studies sectoring in a single plant has 
not been observed. The sectoring has so far always occurred in 
colonies. Although the data are insufficient for positive proof the 
