Parasitic Fungi of Illinois. 171 



are substantially identical, except that in the former the teleu- 

 tospore consists of a single cell, and in the latter of two cells, 

 formed by a horizontal septum usually placed somewhat below 

 the middle. The aecidium and uredo forms of the two genera 

 are not distinguishable. That the two genera are very 

 closely allied is also shown by the fact that in some species of 

 rromyces two-celled spores are met with, while, especially when 

 not fully nourished, single-celled spores are quite common in 

 certain Pmcinice. Occasionally more than two cells are ob- 

 served in true Pmcinia spores, but in this case there is less dif- 

 ficulty in determining the classification, because the spores in 

 genera characterized by two or more transverse septa (Phrag- 

 midium, etc.) are considerably different in appearance. 



In exact strictness each cell in all these divided forms 

 should be called a spore, for each is independent of the others 

 in germination. Some have even called the whole body a spore 

 sack (ascus), and the single cells spores; but there is no dis- 

 tinct wall for the former. 



The genus has been divided as follows: 



1. Leptopuccinia. Only teleutospores produced, which 

 are firmly attached to their stems and germinate soon after 

 maturity; sori quite firm, mostly hemispherical. 



2. Micropuccinia. Only teleutospores known, these read- 

 ily separating from the pedicels, germinating only after a long 

 period of rest. 



3. Hemipuccinia. Uredo- and teleutospores known, 

 aecidia not known. 



4. Pucciniopsis. ^Ecidia and teleutospores known, uredo 

 wanting. 



5.* Eupuccinia. JEcidia, uredo- and teleutospores known. 



a. Autopuccinia. All sporeforms on the same plant. 



b. Heteropucdnia. ^Ecidia (and spermagonia) on a 



different host species from the uredo- and teleuto- 

 spores. 



The third division now undoubtedly contains many species 

 which further information will transfer to the fifth, and the 

 same may be said, with less probability, of the fourth. Since 

 this classification is not applied in what follows, we simply cite 

 as examples of the first: P. anemones-virginiance, Schw.; P. 



