1916] 
DUGGAR—THE TEXAS ROOT ROT FUNGUS 15 
pletely encircled before the fungus extends to the branches. 
If recovery of affected stalks oceurs at all, it is usually by the 
produetion of very superficial laterals. 
I have not made a careful study of the distribution of 
hyphae in the various tissues, nor of the mechanism of pene- 
tration. From the variety of plants affected it may be in- 
ferred that direct infection by the hyphae is general. The 
presence of lentieels on the enlarged part of the root of cot- 
ton by midsummer may possibly be related to the greater 
susceptibility of this plant, and may also be a factor in de- 
termining the frequency of the centrifugal type. 
During the seasons of 1901-09 a careful search was made 
for spore stages of the Ozoniwm, and while several basid- 
lomycetous fungi were found on old cotton stalks in areas 
where cotton had died from the disease, still no case was 
observed which, upon careful examination, proved worthy of 
experimental study. In the examination made of such ma- 
terial special care was given to the characters of the myce- 
lium. However, while examining a semicircular area of dead 
cotton on the edge of a cotton field in 1902, my attention was 
caught by a buff-colored circular spot on the ground just out- 
side the cotton field in an area of grass and weeds wherein 
several of the latter had died from the Ozoniwm. The ma- 
terial observed proved to be an incrustation, or light powdery 
layer, of spores covering about one square foot in area. One 
small area of a few square inches only, considerably weath- 
ered, was found between the rows of cotton. Removing 
the soil with some of the spore material and making an 
examination under the hand lens it was found that strands 
of the Ozonium pervaded the whole mass, and thus there was 
presented the possibility of a spore form genetically connected 
with the Ozonium. Subsequently, the spore material was 
studied more carefully. At that time it was clear that 
strands of the Ozoniwm were present under the masses of. 
spores, but the observations afforded no evidenee of the 
method of spore production. The masses of small spheroidal 
spores formed a layer sometimes 3 mm. in thickness, and while 
the broken bits of hyphae observed resembled those of the 
zonium, no light was thrown on the relation of spores to 
mycelium. The conditions so much resembled those under 
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