Mimulus repens (Creeping Monkey Flower) is common native plant in salt marshes and swampy places. It is a low growing (often prostrate) herb with quite rounded, shiny green, opposite leaves about 5-10mm long, and conspicuous mauve flowers with yellow throats. The only confusing species is Mazus pumilio, but that species has leaves in a rosette and flowers with a very small upper lip and a large, three-lobed lower lip.