Ceratobasidium cornigerum
Ceratobasidium cornigerum is a species of fungus in the order Cantharellales. Basidiocarps (fruit bodies) are thin, spread on the substrate out like a film (effused) and web-like. An anamorphic state is frequently obtained when isolates are cultured. Ceratobasidium cornigerum is saprotrophic, but is also a facultative plant pathogen, causing a number of economically important crop diseases, and an orchid endomycorrhizal associate. The species is genetically diverse and is sometimes treated as a complex of closely related taxa. DNA research shows the species (or species complex) actually belongs within the genus Rhizoctonia. Taxonomy Corticium cornigerum was first described in 1922 by mycologist Hubert Bourdot, who found it growing in France on dead stems of Jerusalem artichoke. It was subsequently transferred to the genus Ceratobasidium by American mycologist Donald P. Rogers in 1935. Molecular research, based on cladistic analysis of DNA sequences, places Ceratobasidium cornigerum within the genus Rhizoctonia, but this taxonomic problem has yet to be resolved. Anastomosis groups (AGs) Ceratobasidium cornigerum is one of several species whose anamorphic states are sometimes referred to as "binucleate rhizoctonias". These binucleate rhizoctonias have been divided into genetically distinct "anastomosis groups" (AGs) based initially on hyphal anastomosis tests, subsequently supported by analyses of DNA