LIPE HISTORIES OF FUNGI 275 



wind to the leaves of nearby barberry bushes, where they 

 germinate. The resulting myceHum 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 Austraha where 

 barberries do not grow, the barberry stage is eliminated. 

 Soon this mycehum 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 



,~ TT TT 



Urediniospores (early summer) Teliospores (late summer) 



4-4- . J-i 



Germination Rest (Nuclear fusion) 



Mycelium Germination 



ii 4-4- 



Urediniospores Basidium 



4-4' 4' \Redtiction 



Germination Sterigmata 



ii 4. 



Etc. Basidiospores (sporidia) 



I 



To barberry 



4. 4. 



Pycnia ^cia [Cell-fusion) 



I i4. 



? ^ciospores 



Rust- on grain 



Near the lower epidermis are formed the ''cluster- 

 cups," or (Ecia^ (aecidia). They break through to the 

 ^ Sing, oscium. 



