614 
Journal of Agricultural Research 
Vol. XXVII, No. 8 
Viala and Pacottet (55) report that they had no success whatever in 
germinating ascospores in culture. They used ascospores which germi¬ 
nated on heads developed from the old mycelium in roots kept several 
months in damp chambers. This method would open the way for 
contamination. The writer’s cultures were all obtained from single 
- ascospores germinated in Petri dishes and transferred each to a tube of 
nutrient agar; later cultures were obtained by transfer from these. 
Viala and Pacottet found no difference in the color of the mycelium on 
the different media used, all having shown a malachite green. The 
writer found this green color fairly constant except on the kidney-bean 
media to which tartaric acid and sugar were added. In this medium 
a slight green color was observed in the early stages of growth, but for 
the most part a greenish-yellow color obtained, noticeable particularly 
on the solid medium and to some extent in the liquid medium. The only 
yellow color mentioned by Viala and Pacottet was in connection with 
what they thought were conidiophores, which they noted were white to 
yellowish in the early stages, and their “chlamydosporic fruits” which 
were yellow when young. The conidiophores described by them in some 
of their older cultures have not been observed in the writer’s cultures 
at any time, although some of them are more than two years old. As 
for the chlamydosporic fruits of Viala and Pacottet, structures with such 
appearances are often found in old cultures of fungi and have no sig¬ 
nificance. 
SUMMARY AND CONCLUSIONS 
Whether the name Pilacre should be applied to an ascomycete or not 
is impossible to say until the nature of Fries’ specimen of P. weinmanni 
is known ( 12 ). Without such an investigation, just as pointed out by 
Bayliss-Elliott and Grove (<?), any attempt to settle definitely the question 
of priority with regard to the names which have been applied to the grape 
and apple rootrot fungus would be premature. 
The Roesleria of von Thiimen (52) is an ascomycete which can be 
grown easily in culture from ascospore to ascospore. The spores are 
sometimes septate on germination, producing one or two germ tubes. 
This fact has led some to suggest that it belongs in the family Geoglos- 
saceae. A fine septate felty mycelium is formed, which both in culture 
and frequently on the roots shows a characteristic malachite green. 
Ascocarps are formed in culture in the refrigerator, where the dark, cool 
conditions simulate the natural soil conditions where ascocarps mature 
in the fall of the year. Notwithstanding the fact that ascocarps were 
frequently formed only after the agar had dried out considerably, this 
dryness is clearly not a necessary condition, because fruit bodies were 
formed sometimes on the weft of hyphae floating on the water in the 
bottom of the test tubes containing sterilized roots which were used 
instead of an agar medium (PI. 1, D). The strain from apple rootrot 
is evidently the same as that found on grape, since inoculations of grape 
roots with the strain from apple have resulted in the formation of 
similar ascocarps. 
In discussing the relationship between Pilacre and Roesleria, Bayliss- 
Elliott and Grove {8) state: 
Moreover it became evident that it would do no violence to the facts if it were con¬ 
cluded that Pilacre faginea and P. petersii were also identical with each other, and 
that both resembled the Roesleria so much in character as to make it seem not unlikely 
that Pilacre is only a stage of Roesleria. 
