254 
C. W. EDGERTON 
Explanation of Plates XXII and XXIII 
Plate XXII. Plus and minus strains of Glomerella. i. Plus and minus 
strains of the Cottonwood Glomerella in a single colony, showing the minus strain 
with the numerous perithecia confined in the central portion of the colony with the 
white plus strain on the outside. 2. Plus (right) and minus (left) strains of the 
Cottonwood fungus with the line of perithecia between them. 3. Plus and minus 
strains of the Glomerella from okra. 4. Section across boundary line between plus 
and minus strains; perithecia just forming. 5. Section across boundary line between 
plus and minus strains; perithecia mature. 6. Perithecium from the boundary line 
between the plus and minus strains showing the ascospores in a droplet at the orifice. 
Plate XXIII. Plus and minus strains of Glomerella. i. Plus and minus 
strains of the Glomerellas from cottonwood (left) and morning glory (right) showing 
the boundary line of perithecia between the two strains from the same host but not 
between the two strains from different hosts. 2. Plus and minus colonies of the 
morning glory Glomerella on oat juice agar, isolated from a colony that developed 
from a single ascus from the boundary line between the two strains. 
