Current symbiont phylogenies and hypothesized Escovopsis relationships. (a) Cultivar phylogeny simplified from [9-11] (b) Escovopsis phylogeny from . This phylogenetic reconstruction, the most complete to date, includes very few Apterostigma-associated pathogens. (c) Hypothesized Escovopsis phylogeny in which there are four distinct Escovopsis clades corresponding to the four known cultivar clades. In this hypothesized phylogeny, the Pterulaceae-attacking pathogens are distinct from the Lepiotiaceae-attacking pathogens. * indicates Apterostigma-associated symbionts. Note that the only Apterostigma-associated symbionts outside the G2/G4 clade are those isolated from colonies of A. auriculatum, the only Apterostigma sp. that does not cultivate pterulaceous fungi [11, 13]. See introduction for further details.