COVERED SMUT 



719 



sible to infect one kind of cereal with the ' smut ' spores obtained 

 from another species. 



(ii) Wheat-' Smut ' {Ustilago Tritici ]ens.). 



The fungus destroys the walls of the ovary and the glumes, and 

 the chlamydospores are blown 

 away from the plant before har- 

 vest. Each chlamydospore is 

 round or oval, olive -brown, 

 with a slightly rough outer coat, 

 and on germination produces 

 a promycelium which does not 

 bear conidia. 



Brefeld states that the entry 

 of 'smut '-fungi into wheat takes 

 place through the flowers chiefly 

 and rarely, if at all, through the 

 young plants, as in oats. 



(iii) Barley-' Smuts.' 



Two species of Ustilago are 

 met with upon barley, namely, 

 Naked or Loose 'Smut' {U. 

 nuda Jens. = U. Hordei Bre- 

 feld) and Covered 'Smut' {U. 

 Jensenii Rostr. = U. Hordei 

 Pers.). The former, which is the 

 more common in this country, 

 destroys the ear and its chlamy- 

 dospores are blown away before 

 harvest {A, Fig. 241). The 

 chlamydospores of this species 

 produce a promycelium which 



bears no conidia (II, Fig. 242) FiG.24i.—yS, Naked 5mutofbarIey(yi«<8?» 

 , J. . • V J nuda Jens.); 5, covered smut of barley C£/i- 



and cannot be dlStmgUlSnea /,7a^(,/e„„MK Rostr.) (natural size). 



from those of U. Tritici except by infection experiments. 



