PLATE I 
The reaction of Pentad, Kubanka No. 8, and F3 hybrids to biologic Form XXXIV. 
A. —Pentad, the resistant parent, normally giving the o-type of infection with an 
occasional uredinium. 
B. —^Kubanka No. 8, the susceptible parent, giving numerous uredinia more or less 
surrounded by chlorotic areas. 
C. D, E.—^Typical F3 families that appeared resistant, heterozygous, and suscep¬ 
tible, respectively. 
