Xerotrema

Only a single species, so the description of X. megalospora is that of the genus.

References: Purvis et al. 1992.

Thallus immersed, not producing a stain, lacking algae, or with small amounts of Trebouxioid or Trentepohlioid algae; apothecia round, developing below the wood or bark grains, bursting through the substrate as it emerges; rim black, radially tattered, the tatters arching over the disc; disc whitish; hymenium formed of straight paraphyses weakly embedded in gel; asci thin-walled; spores 1 per ascus, muriform with numerous cells; known from wet forest in central BC, to be sought …[Xerotrema megalospora Sherw. & Coppins]