Epigloea diversispora is newly described from a coastal mountain summit in western Oregon, U.S.A. The species has minute, shiny, jet black ascocarps appearing on a biofilm of mixed cyanobacteria and algae. The spores are diverse in both shape and septation. Immature spores are initially nonseptate and ellipsoid, then become soleiform, then 1-septate, while mature spores are 3-septate and short fusiform. Lichenization is uncertain, but the species appears to form a loosely lichenized thallus with hyphae dispersed in a partly cyanobacterial and partly algal crust on thin soil, moss, and plant detritus, over rock.