Abstract
In this essay, we focus on the micro-xylariaceous genera (with inconspicuous ascomata and asexual morphs) in the Xylariomycetidae, with special emphasis on Xylariaceae. Are micro-xylariaceous less diverse than macro-xylariaceous genera (with conspicuous stromata) genera? This paper also reviews their taxonomic significance and current systematic relationship and evaluates different characters used in their taxonomic placement. So far, only a few micro-xylariaceous taxa have been studied in detail in comparison with the stromatic macroscopic xylariaceous taxa and the reasons for this are discussed. It is hoped that further sampling and study of different substrata and habitats, with greater emphasis on sequence data, may lead to the discovery of many more micro-xylariaceous genera.