On the co-occurrence of species of () and ().

Species of the genus are collected in association with a subterranean mass generally referred to as a sclerotium. This is one of the few genera of the not associated with plant material - wood or leaves. The sclerotium is composed of hyphae of both species and species. To verify the existence of species in the sclerotia of those species not previously examined and to fully understand the structure and nature of the sclerotium, molecular data and morphological characters were analyzed. Using nuclear ITS rDNA sequences the species co-occurring with species were identified from all examined material. These symbionts fall into two main groups - the group and the group. Divergent time estimates of the and lineages support a co-evolutionary relationship between these two fungi.