J'eb. 15,1925 Root Rot of Grapevine Caused by Clitocybe Tabescens 351 
became yellowish white to buff and the 
central part darker and often orna¬ 
mented with brownish fibrils. The 
gills were pure white at first and dis¬ 
tinctly decurrent. No evidence what¬ 
ever of an annulus was seen. As a rule, 
about a week was required for the 
embryonic sporophores to develop to 
maturity and shed spores, after which 
they quickly became sodden and dis¬ 
colored. Occasionally, the develop¬ 
ment of the sporophores was checked, 
and they dried up before shedding 
spores. 
The Missouri form causing the 
grapevine root rot behaved essentially 
the same in culture as did the euca¬ 
lyptus form from Florida described in 
of cultures and in other miscellaneous 
ones were an exact counterpart of these 
developed by cultures of the Florida 
form, and the writer is convinced that 
these two forms of root rot represent 
simply two different strains of the same 
fungus, namely, Clitocybe tabescens. The 
more luxuriant development of rhizo- 
morphs and stronger tendency to de¬ 
velop sporophores exhibited by the 
Florida form may possibly be an ac¬ 
quired environmental character. 
On June 30, 1923, a series of cultures 
of the Florida form was started from 
basidiospores taken from a spore print 
cast on the side of the tube in which a 
group of mushrooms had developed in a 
former culture. This series was made 
Table I.— Flask cultures for comparison of the Florida and Missouri strains of 
Clitocybe root rot 
Number of days required for— 
Culture medium and number of 
culture 
Source of organism 
i 
i 
1 
Appear¬ 
ance of 
rhizo- 
morphs 
Dif¬ 
ferentia¬ 
tion of 
sporo¬ 
phores 
Matura¬ 
tion of 
sporo¬ 
phores 
Pieces of Vitis aestimlis root: 
Eucalyptus from Florida.. 
22 
44 
50 
2_ _ ! 
Grapevine from Missouri__ 
15 
3__ ... _! 
__do._____ 
31 
76 
83 
4 ! 
...do__ __ 
33 
5_! 
_do____ 
37 
6_! 
.do...... 
37 
Maltose agar: 
1__ .... _j 
Eucalyptus from Florida. 
7 
37 
50 
2____j 
Grapevine from Missouri__ 
22 
75 
86 
3_ ... 
do_ 
35 
4.. ... 
. ..do. _ . 
35 
77 
87 
5_ _ . ! 
do. . 
37 
6.____ 1 
.. ..do.. . 
37 
Raisin agar: i 
1_ 1 
2.__! 
Eucalyptus from Florida__ 
Grapevine from Missouri_ 
7 
18 
36 
42 
3___ ! 
_do..... 
18 
4____ 
_do____ 
18 
5. ... _ 
do.. .. . 
21 
6_ 
do _ 
35 
j 
1 
the four preceding paragraphs, differing 
only in that it gave a very meager and 
more delayed development of rhizo- 
morphs as compared with the latter. 
The Missouri form likewise developed 
fruiting bodies in the cultures much 
more slowly and with much more diffi¬ 
culty than the Florida form. The 
development of these two forms of 
Clitocybe tabescens may be compared in 
Table I, which shows the length of 
time required for each to reach certain 
definite stages of development on three 
different substrata. Inasmuch as the 
writer left Missouri, the cultures were 
abandoned after the lapse of 110 days. 
The fruiting bodies which the writer 
succeeded in developing from the cul¬ 
tures of the Missouri form in this series 
with a view to determining the length 
of time required to run this fungus 
through its full life cycle from spore to 
spore and to compare this with the 
length of time required for mycelial 
transfers of the same form to produce 
fruiting bodies. Unfortunately, spores 
of the Missouri form were not available 
at this time, nor was the opportunity 
afforded the writer of collecting material 
in the field to furnish spores; so that no 
comparison can be made between the 
two forms of Clitocybe tabescens grown 
from the basidiospores. 
The results of the experiment with 
the Florida form, presented in Table 
II, indicate that it makes no difference 
in the length of time required for this 
form to develop fruiting bodies, 
