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C. W. EDGERTON 
ascogenous anthracnose cultures, an attempt was made to produce 
this between these strains and ascogenous cultures from other hosts. 
Plantings were made in the same plate of both of the strains from the 
Cottonwood and also both of the strains from the morning glory so 
that either strain would come in contact with both of the opposite 
strains. As the colonies developed, the plus strain of each host came 
in contact with both of the minus strains. Perithecial ridges developed 
between the plus and minus strains of the cottonwood fungus and be- 
tween the plus and minus strains of the morning glory fungus, but no 
sign of a ridge formed between the plus strain of the cottonwood fungus 
and the minus strain of the morning glory fungus or between the minus 
strain of the cottonwood fungus and the plus strain of the morning 
glory fungus. One of these plates is shown in Plate II, figure i. The 
prominent perithecial ridges are between the plus and minus strains 
of the same host. 
These experiments seemed to cast doubt on the possibility of this 
perithecial development being due to a chemical or mechanical stimu- 
lus. It would seem, if this were the cause, that some of these very 
closely related forms would also have provided this stimulus. These 
experiments strengthened the theory that the perithecial development 
was really due to a fertilization between two sexual strains. 
To prove that there was really a fertilization between the strains 
was a rather difficult proposition. The mycelial development is so 
profuse in the plates that it is impossible to tell by examination whether 
both strains enter into the formation of the perithecium or not. In 
order to get some data on this point, an attempt was made to culture 
the ascospores that developed in a single perithecium on the boundary 
line. The ascospores of a Glomerella are shed very quickly after 
they form and they ooze out of the perithecium and remain in a little 
droplet at the orifice (Plate I, fig. 6). Dilution cultures were made 
from these little droplets of spores that had oozed out of single peri- 
thecia. If there was a cross fertilization, it would be natural to sup- 
pose that the spores developing in a single perithecium would develop 
into two strains while if there were no crossing and the ridge of peri- 
thecia on the boundary line was but due to some chemical stimulus, all 
of the ascospores would develop into but a single strain in the same 
manner as all of the ascospores from a single perithecium from a single 
strain do. Plates from nineteen different perithecia were made and 
of these seventeen showed colonies of both strains. In the other two 
