Journal of Agricultural Research 
Vol. XXIII, No. 9 
694 
DEVELOPMENT OP APOTHECIA UNDER ARTIFICIAL CONDITIONS 
Immediately upon receiving the intimation of the existence of a 
perfect stage of this organism the writer took steps to work out a 
means of producing apothecia under controlled conditions. In view of 
the fact that the only apothecia found at first were from tissue transfer 
cultures (isolation record, p. 688, B 1 and B 21), it was thought that the 
fungus might be heterothallic. Consequently several cultures were made 
consisting of mixtures of pure-line strains in various combinations of 
single-conidium, single-ascospore, and tissue-fragment cultures. No dif¬ 
ferences were noted in the development of sclerotia; and, as soon became 
evident, there were no differences in apothecium production. A number 
of other experiments were started, consisting principally of subjecting 
sclerotia to different conditions with the idea of determining their effect 
on apothecium production. An account of these experiments follows. 
Experiment III.—March 12. Some sclerotia from the field, one of them large, 
widespread, and flat, were placed on a layer of moist sand on a glass plate, and the 
whole was covered with a battery jar. This was placed on the laboratory table near 
a window. It was watched carefully for several days without developments, then, 
in the stress of other work, was neglected for some time. During this period the 
sand became quite dry. Notwithstanding this, onjApril 16 five apothecial stalks 
were seen to have risen from the large flat sclerotium. One was about 1 cm. long 
and 1% mm. wide at the end, all the others being not so fully developed. The sand 
was at once moistened before the apothecia had suffered materially. These will be 
designated lot III A At the same time additional sclerotia, which we shall call 
lot III B, were incubated as follows: 
Sclerotia from the field. 
Sclerotia from strain B 21 B (1). 
Sclerotia from strain B 21 C (a) 1, 4, and 7. 
These sclerotia were placed on moist sand in well-marked positions and covered 
with a battery jar, under laboratory conditions. 
Observations were recorded as follows: 
Lot III A. April 24. The largest apothecium, already noted, is developing very 
irregularly. The second has a perfect disk 1% mm. in diam. The third, half as 
large, has a hollow end. The fourth is somewhat shriveled, and the fifth is growing. 
April 26. The first apothecium in its irregular growth is developing two smaller 
distinct disks on the side of the first. 
April 29. Early in the morning the bell jar was lifted, and the second apothecium 
was observed to shoot forth ascospores in a distinct cloud. April 30, the bell jar was 
lifted again, and the spores when ejected were caught on a plate of clear corn-meal 
agar. Single ascospore isolations were made. Apothecia I and II of this lot were 
photographed and later preserved in alcohol. The third was sent to Prof. Whetzel at 
Cornell University. 
May 9. A dozen or so more apothecia, well developed, were noted from this lot. 
Lot III B. May 6. Apothecial stalks are developing from both field and pure 
culture sclerotia. 
May 10. One or two apothecia from the field sclerotia are nearly mature. 
May 15. An apothecium from a sclerotium developed in tube B 21 C (a) 4 is mature, 
as shown by the appearance of a cloud of spores when the cover was lifted. This 
particular group of sclerotia was isolated from the others and covered separately. 
May 16. The cover was lifted and ejected spores were caught on a poured plate 
of corn-meal agar. 
May 17. Another “volley” was caught, the first being too thickly sown. Single 
spore isolations were made, these therefore being second-generation ascospore cul¬ 
tures. That is, starting with an ascospore, the culture has gone through its entire 
life history, gray mold, sclerotium, apothecium, and a new generation started with 
an ascospore. 
Experiment III demonstrates that under favorable conditions of 
moisture and temperature apothecia can be produced extensively. It 
also shows that single ascospore strains of the fungus are in themselves 
capable of producing all the stages of the life history of the fungus— 
that is,^the fungus is purely homothallic. 
