Mesosetum chaseae Luces, known regionally as “grama-do-cerrado”, is abundant in the Pantanal region in Brazil and contributes significantly to livestock and environmental conservation. This species is under basic studies at Embrapa Pantanal (Nhecolândia subregion, Pantanal, Corumbá, MS, Brazil). In this study, we present data about stigma receptivity, mode of reproduction, and mating system for 10 accessions collected in Nhecolândia subregion (Pantanal). Stigma receptivity was optimal, producing innumerous oxygen bubbles upon testing with hydrogen peroxidase. Clarified ovaries analyzed under interference microscopy showed an embryo sac of the Polygonum type, typical of sexual species. The mating system, tested in protected flowers, indicated allogamy. These data are important for subsidizing future breeding programs for this species.