[2][3] The genus was circumscribed by the Swiss lichenologist Johannes Müller Argoviensis in 1890, with M. uleana assigned as the type, and at the time, only species.

[5] Microtheliopsis is a genus of lichen-forming fungi that primarily grows on the leaves of understory plants and shrubs (epiphyllous and foliicolous).

[6] The ascomata (sexual reproductive structures) are flask-shaped (perithecial) and small, appearing as solitary, scattered bumps that are easily visible on the leaf surface.

These perithecia are dark brown to black, rounded or slightly elongated, and partially embedded in the algal layer of the thallus.

They are surrounded by irregular, dark brown fungal filaments (hyphae) and have a small opening at the top (ostiole) for spore release.