It is endemic to western tropical Africa, where it is only known from the mountain ranges of Guinea and Sierra Leone.

U. macrocheilos grows as a terrestrial plant among wet rocks at medium altitudes.

Peter Taylor recognized these specimens as a different taxon in a 1963 review of African species and treated it as a variety of U. micropetala.

After further discussions with other botanists and review of the specimens, he elevated the variety to the species level in 1986 as U. macrocheilos.

Compared to U. micropetala, U. macrocheilos has much longer corolla lips and less acute fruiting calyx lobe apices.