PROTOBASIDIOMYCETES 389 



1. Pucciniaceae. The teleutospores usually consist of a single 

 cell or a vertical row, sometimes, however, united into the form of 

 a relatively small head. The spores are borne on a simple or com- 

 pound pedicel. The uredospores are single, on hyaline, deciduous 

 pedicels. The aecidia are generally provided with a well-developed 

 peridium. The genera here considered are Uromyces, Puccinia, 

 Gymnosporangium, Gymnoconia, Phragmidium. 



2. Cronartiaceae. The teleutospores are without pedicels, and 

 they originate in chains, or series, more or less free at maturity, or 

 united into complex bodies. Chrysomyxa and Cronartium are the 

 important genera. 



3. Coleosporiaceae. The teleutospores are united into a layer 

 generally wax-like in texture, and orange-red in color. The spores 

 are generally without pedicels, at first unicellular, but soon dividing 

 into four cells, that is, to form the promycelium within the spore, 

 each cell of which, therefore, produces a sterigma and basidiospore. 

 The genus Coleosporium includes the more important species. 



4. Melampsoraceae. The teleutospores form a closely adherent 

 crust-like layer, each cell of which germinates by a typical promy- 

 celium. The uredospores are borne singly, and the aecidia are with 

 or without peridia. Melampsora is the chief genus. 



The genera above mentioned may be briefly described as follows : 



Uromyces. The teleutospores are unicellular with a terminal 

 germ pore ; the uredospores are generally provided with many evi- 

 dent germ pores ; the aecidia are provided with peridia, the aecidio- 

 spores are without germ pores, and the spermogonia are spherical 

 with minute circular ostiola. 



Puccinia. This genus is similar to Uromyces except that the 

 teleutospores are two celled. Unicellular teleutospores may also 

 occur in some species. 



Gymnosporangium. The teleutospores are commonly two celled, 

 exceptionally three or four in a row. They are borne in pustules ; 

 and, at maturity, owing to the development of substances resulting 

 partially from the gelatinization of the long pedicels, they are 

 pushed out into jelly-like masses, sometimes horn-like in form. 

 The spores are often provided with several germ pores arising 

 near the side wall, though apical germ pores may be present. 

 There are no uredospores, and the aecidia (rcestelia) are often 



