Abstract: Species of the genus Wynnea are collected in association with a subterranean mass generally referred to as a sclerotium.
This is one of the few genera of the Sarcoscyphaceae not associated with plant material – wood or leaves. The sclerotium is
composed of hyphae of both Armillaria species and Wynnea species. To verify the existence of Armillaria species in the sclerotia of
those Wynnea 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 Armillaria species co-occurring with Wynnea
species were identified from all examined material. These Armillaria symbionts fall into two main Armillaria groups – the A. gallicanabsnona-
calvescens group and the A. mellea group. Divergent time estimates of the Armillaria and Wynnea lineages support a
co-evolutionary relationship between these two fungi.