44 MICROSCOPIC FUNGI. 



The result of these investigations sliows tliat the 

 bean-rust {Uromyces ai^pendicidatiis) , besides sper- 

 mogones^ possesses four sorts of reproductive or- 

 gans^ whicli all serve to propagate the species^ but 

 that one alone of them produces it in a form always 

 identical^ whilst the others present well-marked 

 alternations of generation. Hence it is concluded 

 that there are, 



I. Spores which produce in germinating the pro- 

 mycelium, and 



II. Sporidia. — These give place to a mycelium, 

 which bears afterwards — 



III. ^cidium, — Particular organs which engen- 

 der stylospores, and which produce — 



IV. Uredoy the second form of the stylospores, 

 and later spores (No. I.), which are always asso- 

 ciated with JJredo in the same pustule. The spores 

 and stylospores of JJredo come also upon the old 

 mycelium, which has previously produced ^cidiiim'. 

 The JJredo stylospores always produce JJredo^ and 

 true spores. 



