^CIDIACE^. 173 



forming under the epidermis of leaves, petioles, and even 

 flowers. They are of far greater importance than the first 

 series, since they are very destructive to the different kinds of 

 fruits and cereals. They are commonly called ruts and brands. 

 Dualism is frequently met with in this series in the form of 

 uredospores or rust, and teleutospores or brand ; the former 

 stage is also called the summer spores, and the latter the winter 

 spores. This class of fungi are frequently called microscopical 

 fungi, since their identity can not be accomplished unless you 

 bring to your aid a good compound microscope of a medium 

 power, with a one-fifth objective. To study this series of 

 Uredines a person ought to be well acquainted with our 

 phanerogamous plants, especially with the specific botanical 

 name, for the parasite is generally named after the specific 

 name of the plant. 



The natural orders included under the parasitic Uredines are 

 as follows : 



^CIDIACE^. 



PUCCINIACE^. 

 Cooke, in his British Fungi, has a large natural order under 

 this group, Caeomacei, the genera of which are now included 

 under the above two natural orders. 



Order I. ^CIDIACB^. 



Peridium distinctly cellular, cup-shaped, margin free. 



The following genera are included, viz : 



RcESTELiA. — Peridium elongated. 



Peridermium. — Peridium elongated, growing only on pine 



needles. 

 -^CIDIUM. — Peridium cup-shaped, margin recurved. 

 C^OMA. — Spores in vertical chains, with spermogonium. 



