The coelomycete Melanconiopsis microspora is introduced as a new species from bamboo culms collected in Argentina. Its comparison with the type species of the genus, M. inquinans (from which it differs in the smaller conidia), also resulted in a reappraisal of M. olivacea which is referred back to Sphaeropsis as S. olivacea, the third accepted species in the genus. M. elzoi is probably accommodated in Endomelanconium as a fourth accepted species; notes on the known species in this genus are given.