PROTOBASIDIOMYCETES 



411 



first as small, flask-shaped bodies, shown in Fig. 202, breaking 

 through the upper epidermis of the leaf. Somewhat later, and 

 in the same spot, there appear on the under surface the aecidial 



Fig. 202. Puccinia graminis. (After Ward) 

 , section of barberry leaf showing spermogonia and ascidia ; b, secidium 



stage, which breaks through the epidermis in somewhat similar 

 manner. The spermogonium shows a very simple development, 

 resulting by the gradual growth in extent of a small mass of fila- 

 mentous hyphse developing in an intercellular manner just beneath 



