Erythranthe nudata

Erythranthe nudata, the bare monkeyflower, is a species of monkeyflower endemic to the serpentine soils of Colusa, Lake and Napa Counties in California. It is an annual flower with bright yellow tube-shaped blooms and small narrow leaves.

Taxonomy
Erythranthe nudata is a member of the Erythranthe guttata species complex, a group of closely related wildflower species that vary dramatically in mating system, life history and edaphic tolerance. Species in the E. guttata complex are largely inter-fertile, with some notable exceptions. In particular, E. nudata is reproductively isolated from other complex members via a postzygotic isolating barrier during seed development.