Homothallism and monosporous mycelia in Coprinus. 215 
XI. CONCLUSIONS. 
1. Coprinus sterquilinus, C. lagopus, C. stercorarius, C. niveus, 
C. ephemerus, C. curtus, C. stellatus, and C. cordisporus all pro- 
duced rudimentary fruit-bodies on a mycelium which originated 
from a single spore. In C. sterquilinus, C. lagopus, C. stercoraris, 
C. niveus, and C. curtus, these fruit-body rudiments developed 
into perfect fruit-bodies which shed ripe spores. In C. ephemerus, 
C. stellatus and C. cordisporus, under the conditions of culture 
employed, the fruit-body rudiments remained as such and never 
developed into perfect fruit-bodies. 
2. Both monosporous and polysporous mycelia of Coprinus 
comatus failed to produce fruit-bodies in dung cultures. 
3. Brefeld’s statement that fruit-bodies of Coprinus  ster- 
corarius, C. lagopus, and C. ephemerus are produced on a 
mycelium which has developed from a single spore, has been 
confirmed. 
4. As determined by clamp-connection criteria, Coprinus 
sterquilinus, C. lagopus, C. stercorarius, and C. niveus are homo- 
thallic, and C. comatus heterothallic. 
5. Coprinus curtus, C. stellatus, and C. cordisporous do not 
produce any clamp-connections on any of their mycelia whether 
of monosporous or of polysporous origin. It was therefore found 
impossible to decide by clamp-connection criteria whether these 
three species are homothallic or heterothallic. 
6. Coprinus sterquilinus was successfully cultivated in pure 
monosporous cultures for five successive generations. The 
mycelium of the fifth generation was just as vigorous and 
fruited just as rapidly as the mycelium of the first generation. 
The cultivation of C. sterquilinus from mycelia of monosporous 
origin does not, therefore, appear to weaken the fungus in any 
way. 
7. The spores of Coprinus sterquilinus germinate freely in 
perfectly sterile potato agar and dung agar. Incidentally, there- 
fore, I find myself in agreement with Buller and Churchward 
who, in a paper as yet unpublished, state that the spores of 
C. sterquilinus germinate readily without the presence of 
bacteria. 
8. The monosporous mycelia of Coprinus niveus which is 
homothallic, exhibit a considerable range of variability in their 
fruiting powers, some producing perfect fruit-bodies, others 
only fruit-body rudiments, and yet others no rudiments at all. 
The mixing of the monosporous mycelia in pairs was found to 
stimulate fruiting in a marked manner. 
g. Both monosporous and polysporous mycelia of Coprinus 
lagopus, when grown on large dung masses in crystallising 
