RUSTS. 121 



together in tlie pustule is shown in plate VIII. 

 fig. 182, from an allied species. When these spores 

 germinate, which they do with great readiness, each 

 division emits a long tube, which generally remains 

 simple and undivided, and from its extremity is 

 produced a reproductive body of an obovate or 

 nearly kidney-shape. These filaments are about 

 T ^th of an inch in length, of a colourless tran- 

 sparent membrane, along which the orange-red 

 contents of the spores pass into the newly-formed 

 sporidia, or reproductive bodies by which they are 

 terminated. Most of these reniform sporidia dis- 

 engage themselves from the filaments on which thev 

 are produced, and either elongate themselves into 

 a simple and uniform filament, or swell at the 

 extremity as if to reproduce a second spore. If the 

 newly-formed sporidia do not become free, they 

 increase the length of their primitive filament, 

 which by a frequent repetition of the process 

 becomes a tube swelling out at unequal distances. 



The summer spores, or pulverulent spores of the 

 first generation, which are analogous to the Uredo- 

 spores of Aregma, are also capable of germination, 

 for, if placed in favourable circumstances, they will 

 develop very long filiform processes, which either 

 remain simple or become more or less branched, 

 but always nearly uniform in their diameter. M. 

 Tulasne states that he has observed this germina- 

 tion many times, though we have been less for- 

 tunate. 



