PLATE 2 
Puccinia graminis tritici form III on Baart (A) and Kanred (B-G) 
A. —Baart. Series showing alterations of nuclei in infected area. X 1130. 
a. Normal nucleus from uninfected tissue. 
b, c, and d. Nuclei from seven-day infection, showing progressive expansion of 
nuclei, increase in nucleoli and loosening of chromatin net. 
e. Maximum size, 10-day infection. 
/, g, and h. Progressive collapse of nucleus. Ten- and 14-day infections. 
B. —Kanred. Four-day infection. Two appressoria at one stoma. Each produced 
a substomataT vesicle (e and f ). The infecting hyphae grew in opposite directions 
and each produced a haustorium, c and d, in an epidermal cell. Outer guard cell 
wall modified at b. X 730. 
C. —Kanred. Seven-day infection. Guard cell killed by appressorium of fungus a. 
Adjoining epidermal cells weakened and broken. X 730. 
D. —Kanred. Seven-day infection. Young haustorium a forming from the mother 
cell b. X 1130. 
E. —Kanred. Seven-day infection. Cell surrounded by vigorous hyphae. Large 
haustorium c from mother cell d. X 1130. 
F. —Kanred. Nine-day infection. Fungus cell from mycelium below uredinium. 
Cytoplasm nearly gone. Nuclei distinct. X 1130. 
G. —Kanred. Eleven-day infection. Mesophyll cell from region where mycelium 
is nearly empty. Haustoria at o, 6, and c also partly drained. Nucleus in hau- 
storia distinct. X 1130. 
