Drosera monantha is a tuberous sundew native to the Wheatbelt around Bruce Rock in Western Australia. This attractive species grows large circular rosettes with diameters of around 12 cm and grows in the drainage fields of granite outcrops. The species can be distinguished from D. bulbosa by its larger, rounder leaves and late flowering season.

Previously, it was considered a subspecies of the very similar Drosera macrophylla. Drosera monanthos can be distinguished by its pedicles, which mostly bear a single (mono-) flower (anthos). This is contrasted to the floral scapes of D. macrophylla, which bear 2-8 blooms per peduncle. It is also geographically isolated from the former, occuring more east inside the Wheatbelt.