PLATE 
3 
Germinating spores of Urocystis tritici, showing origin of a binucleate condition of 
the germ tube on germination of sporidium: 
A. —Sporidium with single nucleus. X 450. 
B. —Sporidium with dividing nucleus. X 450. 
C. —Germ tube with 2 nuclei. X 250. 
Mycelium and spores of Urocystis tritici: 
D. —Intracellular (a) and intercellular (b) mycelium at nodes of infected plants. 
X 45 °- 
E. —Intercellular mycelium, showing first stages of spore formation. X 450. 
F. —Spore formation, early stages. X 450. 
G. —Spore formation, later stages, formed for most part from intercellular mycelium. 
X 45 °- 
H. —T. S. wheat leaf showing mature spores and sporeballs in section. X 200. 
I. —T. S. wheat leaf showing sorus of spores. X 40. 
