20 BOTANICAL GAZETTE - — [JULY 
These variations are inexplicable and remind one of the mysterious 
change from the ascigerous to the non-ascigerous condition. so fre- 
quently met in life-history work with the imperfect fungi. 
Variability in spore measurements 
Since the beginning of mycology it has been customary to give 
spore measurements in specific description, probably originally with 
F 1G. 15.—Coniothyrium Fuckelii Sacc.; portions of two colonies showing circles of 
pycnidia near margins. 
the idea of giving some information as to the approximate size of the 
plant concerned rather than to give exact descriptive limitations. — 
With the advance of time, great importance has come to be attached 
to spore measurements, greater perhaps than is warranted, and many 
species are now founded upon divergence in this one character — 
and often upon slight divergence. 
GF \eatatreir 
i eas et 
re 
Fatt SOC SONS heed i ee 
