PLATE i8 
Helminthosporium sativum 
Aa-b.—Kernels of wheat affected with "black point/* lateral and dorsal views. 
X3. 
Ba-b.—Wheat kernels attacked by H. sativum, showing extensive discoloration 
of embryo and ventral suture; median longitudinal section and lateral view. X3. 
Ca-b.—Wheat kernels showing severe discoloration in region of embryo; lateral 
and dorsal views. X3. 
D. —Portion of mature wheat head, showing grayish efflorescence on glumes, com¬ 
posed of fructifications of H. sativum, X3/2. 
E. —Wheat seedling grown from “black-pointed" kernel showing moderately 
severe infection with H. sativum; discoloration of the basal sheath and two foliar 
spots. XH‘ , 
Fa-q.—Conidia of H. sativum produced on wheat head, showing atypical irregu¬ 
larities in shape, size, and septation. X500. 
Ga-k.—Typical conidia produced on infected leaves of A repens, illustrating 
variation in shape, size, and septation. X500. 
H.—Upper leaves of Agropyron repens attacked by H. sativum, showing abundance 
of small elongated foliar spots. XH 
