This is a first of a series of papers where we bring collaborating mycologists together to produce a set of notes of 50 taxa of fungi, including the new genera Phaeopoacea, Kalmusibambusa and Neoramichloridium, 33 new species, three new combinations, two reference specimens, one epitype, an asexual report and new host records or distribution records for seven species. In this paper, we deal with 50 taxa on grasses (Poaceae or Gramineae). Grasses are ecologically dominant, monocotyledonous plants, which occur in almost every habitat worldwide. In this study, molecular sequence data and descriptions linked to morphological illustrations are used to show the diversity and taxonomy of grass-inhabiting fungal species. Sixty strains of newly collected dothideomycetous species on Poaceae in China, Italy, Russia and Thailand were identified based on morphological characters and analyses of sequence data. This research is expected to stimulate interest in grass fungi.