Astrocystis revisited

Astrocystis species (Xylariaceae) listed in Index Fungorum are revisited. A new species (A. guyanae) and eight new combinations from Rosellinia (A. ambigens, A. dimidiata, A. formosa var. formosa, A. formosa var. flavozonata, A. hemisphaerica, A. marginatoclypeata, A. muroiana, and A. subverruculosa) are proposed, described, and illustrated. A dichotomous key to Astrocystis species is provided, their hosts and distribution are listed, and species concepts are discussed.