150 Illinois State Laboratory of Natural History. 



(2). In the Uredineae the names of the teleutospore and 

 uredospore stages are alone considered in the question of prior- 

 ity. ^Ecidial names are not recognized, mainly from the un- 

 certainty that exists as to the genetic connection of the forms, 

 as well as from the obscurity of descriptions, and the inferior 

 value of herbarium specimens as types. 



(3). The name of the author responsible for the specific- 

 appellation has been appended, being inclosed in parenthesis in 

 case the generic association has been changed; and the name 

 of the author of the binomial combination, whether the parts 

 were adopted from others or not, finally follows. In quite a 

 number of cases this author is not known to us, owing to the 

 too prevalent habit of omitting the citation. 



The descriptions of species are taken from nature, and as 

 far as possible from typical or average specimens. The mea- 

 surements given are intended to include the variations which 

 commonly occur in such specimens; but the extreme limits of 

 exceptionally large or small spores are not indicated. In most 

 cases the measurements were made of spores immersed in a so- 

 lution of potash, so as to obtain the size of the mature but 

 undried specimens. For the study of the surface markings, ex- 

 aminations were made when necessary of spores either dry or 

 wetted with pure water, whichever method was found from 

 experience to produce best the particular effects required. The 

 color given is as closely as possible that of nature rather than 

 an interpretation of the appearance of a few spores in the field 

 of the microscope. It need scarcely be said that the tint is 

 much lighter in the latter case. The best objectives of different 

 makers were used, and for the closer studies a magnifying 

 power of about five hundred diameters was employed. 



It has been deemed worth the while to quote the descrip- 

 tion given by another author; usually, when accessible, the 

 original description of the species in each case. The quoted 

 descriptions are printed in different type, and are followed by a 

 reference, with name, date, and page, of the work from which 

 the extracts are made. 



Notes are appended when required; these follow the col- 

 lector's numbers and designations of localities, and are intended 

 to record any special facts about, or information upon, the 



