PLATE 45 
A. —Flax plants growing on North Dakota "flax-sick soil.” a, Resistant No. 4. 
by Cy Reciprocal crosses between resistant No. 4 and susceptible No. 6. All of 
these F! plants died later of wilt, d, Susceptible No. 6. 
B. —Flax plants growing in North Dakota "flax-sick soil," a, Resistant No. 4. 
by Cross between resistant No. 4 and susceptible No. 5. c, Susceptible No. 5. 
C. —Flax plants growing in North Dakota "flax-sick soil." a t Resistant No. 4. 
by Cy Crosses between resistant No. 4 and susceptible No. 5. d t Susceptible No. 5. 
D. —Flax plants growing in North Dakota "flax-sick soil." a, Resistant No. 4. 
by Cross 4D20 between resistant No. 4 and susceptible No. 3. c, Cross 3E14 
between plants of the same two strains as b . d, Susceptible No. 3 (all dead). 
