LIFE HISTORIES OF FUNGI 275 



wind to the leaves of nearby barberry bushes, where they 

 germinate. The resulting mycelium penetrates the epi- 

 dermis, and ramifies between the cells of the leaf paren- 

 chyma, from which it absorbs nourishment. Under 

 certain circumstances, as for example in Australia where 

 barberries do not grow, the barberry stage is eliminated. 

 Soon this mycelium develops a reproductive structure 

 called the pycnium (pycnidium or spermagonium), which 

 breaks through the upper epidermis and produces innu- 

 merable pycnios pores (spermatia). The real nature of 

 this structure is not known. 



OUTLINE OF LIFE HISTORY OF WHEAT RUST 

 Rust on Grain 



n~ ~TT~ 



Urediniospores (early summer) Teliospores (late summer) 



44 44 



Germination Rest (Nuclear fusion) 



44 44 



Mycelium Germination 



4.4. 4.4, 



Urediniospores Basidium 



4< 4- 4 } Reduction 



Germination Sterigmata 



44 4 



Etc. Basidiospores (sporidia) 



To barberry 



4 4 



Pycnia jEcia (Cell-fusion) 



4 44 



? vEciospores 



44 



Rust on grain 



Near the lower epidermis are formed the " cluster- 

 cups," or (Bcia 1 (aecidia). They break through to the 

 1 Sing, acinm. 



