The rusts so far considered are some of the more ordinary species, 
belonging to the Aecidiacee. There are species in both the Uredinaceze 
and the Coleosporiacee, however, which seem to have the same ability to 
maintain themselves indefinitely in the uredinial stage. 
Among the Uredinacee two of the most Common rusts are’ Welampsora 
Meduse on Populus and M. Bigelowii on Salix, both of which have :ecia on 
Larix, The wecia are so much alike that it is impossible with our present 
knowledge to tell them apart. It seems well here, therefore, to consider 
the two species together, although there are definite morphological charac- 
ters in the urediniospores which mark them as clearly distinct from each 
other. The collections of I. Bigelowii in the Arthur herbarium show its 
presence in nine counties of the State, the first collection being made in 
1887 and the last one in 1914, both in Tippecanoe County. The rust is 
common and the epidemic is usually severe. The only explanation which 
seems reasonable for not having collections from all counties in the State 
is in the lack of collectors being at work in those not represented. J/. 
Meduse@ is represented by collections from five counties in Indiana, and the 
same remarks as to prevalence and severity that were applied to MW. Bige- 
lowti apply to this species also. Both of these rusts have a range also far 
to the southward and westward of this region. Their wcia, to the present 
time, have not been collected nearer this region than New York and Wis- 
consin. However, it is likely that they do occur nearer because the larch 
has a range extending as far south as northern Illinois and northern 
Pennsylvania. It also occurs occasionally as an ornamental tree at various 
places in the State. The w#cia probably occur within the hundred eighty 
nile distance from the northern half of the State and perhaps from all 
parts of the State. It does not seem reasonable to think, however, that 
wcia occur within several hundred miles of the southern range of the fungi. 
The natural assumption is, therefore, that they are able to pass the winter 
in the uredinial stage. 
Bubakia Crotonis, on Croton monanthogynus, has been taken four 
times in Indiana, from at least three counties, and over a period of time 
extending from 1896 to 1912. It also extends as far north and west as 
Nebraska. No cium is known for the rust, but the nature of the fungus 
suggests a Pinaceous host and a Ceomoid cium. Ceoma strobilinum on 
Pinus palustris and Pinus teda has been suggested by Arthur.“ Neither of 
*Bull. Torrey Club 33:519. 1906. 
