1886. ] BOTANICAL GAZETTE. 239 
of the spores of Gymn. clavipes. It is out of the question to 
consider Gymn. globosum and Gymn. clavipes as forms of one 
species both from their habit, microscopic structure, and the dis- 
tortions produced. The species to which it appears to be most 
closely related and with which it is even identified by some 
writers is Gymn. fuscum, a species which is considered by Euro- 
pean botanists to have for its ecidium Roestelia cancellata which 
grows on Pyrus communis. Now although in this country one 
often finds pear trees growing close to red cedars attacked by 
hardly eredible that it has escaped the observation of our botan- 
ists unless it is very rare indeed while Gymn. globosum is very 
common. oe 
With regard to Gymn. macropus we have more definite in- 
formation, although here, unfortunately, the case is not quite 
clear. This species has been studied more than any other, not 
only on account of its great size and abundance, but also on ac- 
