The Sterile Fungus !Rhizoctonia. 



63 



were not to be regarded as distinct, and all were thrown together 

 under the name lihizoctonia violacea. In 1858 Kuhn"^ discussed 

 more at length certain forms of economic importance, and made 

 known some new hosts among agricultural plants. Fuckelf reported 

 a perithecial form, Leptosph(Bria {B yssothecitcm) ciroi7ia7is a,ud also 

 a pjcnidial form of Ji. 'medicagi7i{s D. C. The only claim for the 

 relationship of these forms was based upon their association in nature. 



In a similar way other fungi have been subsecpiently suggested as 

 perfect stages of Rhizoctonia, but evidence of genetic relationship 

 is constantly lackino;. 



Among forms more recently described may be mentioned an oak 

 root-fungus discovered by Hartig.;]: It was found closely associated 



18. — Oerminating cells of the Beet Root-Rot Fungus. 



with the ascomycetous form Rossellinia qicercina, so that the 

 reported rhizoctonial stage was described under the latter name. 



Scholtz§ has described Rhlzoctonea strobi^ causing a disease of 

 the Weymouth pine, and he was unable to establish any connection 

 between the hyphse of this Rhizoctonia and those of certain fruiting 

 forms found on plants killed by this disease. 



* Kiihn, J. — Krankheiten der Kulturgewacbse, Berlin, 1858. 

 f Fuckel.— Botan, Zeitung, 34, 1861 (p. 250). 



:J:Hartig, K. — Untersuch. aus d. forstbotan. Institut zii Munchen, 1888. 

 gScholtz. — Rhizoctonia strohi, ein neuer Parasit der Weymouthskiefer. 

 Verhandl. d. zoolog.- botan. Ges. Wien, 47: 541-557, 1897. 



