PLATE i 
Marquis wheat seedlings, healthy and artificially infected with Helminthosporium 
sativum. The healthy seedling at left was grown from disinfected seed sown in 
sterilized soil. The other six are of the same age and were grown from the same 
lot of disinfected seed but were sown in sterilized soil inoculated at sowing time with 
conidia of H. sativum grown in artificial culture (culture 51a). They show various 
types of primary infection. 
(«8) 
