sentences:  These binucleate rhizoctonias have been divided into genetically distinct "anastomosis groups" (AGs) based initially on hyphal anastomosis tests, subsequently supported by analyses of DNA sequences.At least six of these AGs (AG-A, AG-B(o), AG-C, AG-D, AG-P, and AG-Q) have been linked to "Ceratobasidium cornigerum", which may therefore be considered as a variable species (comprising at least six genetically distinct populations) or as a complex of morphologically similar species.In the latter case, it is not clear which of these AGs (if any) should take the original name "C. cornigerum".