Abstract
An ascomycete with morphological similarities to Astrocystis (Xylariaceae) was collected from the peat swamp palms Eleiodoxa conferta and Licuala longicalycata in southern Thailand and is introduced here. The new taxon is characterized by carbonaceous black stromata on persistent white hyphae, and brown ascospores surrounded by a thin mucilaginous sheath and with a longitudinal germ slit. No anamorph was observed in nature or in culture. Phylogenetic relationships were investigated based on ITS1-5.8S-ITS2, partial LSU and SSU rDNA sequences using maximum parsimony and Bayesian analyses. Phylogenetic analyses of the ITS regions places the taxon in Xylariaceae, in a clade comprising Astrocystis eleiodoxae and Stilbohypoxylon elaeicola with good support and a sister group to Astrocystis, Kretzschmaria, Rosellinia and Xylaria species, with moderate support. LSU and SSU rDNA data places A. eleiodoxae in a clade with A. cocoes, Rosellinia necatrix and Stilbohypoxylon elaeicola in the Xylariaceae. The data indicates a relationship between A. eleiodoxae and Stilbohypoxylon elaeicola. There are no other Astrocystis sequence data available in GenBank, and based on molecular data shown here and morphological data we described Astrocystis eleiodoxae as a new species.