Monkey Flowers prefer very wet conditions. The only place I have seen them in our area was on the edge of a tiny pond in the deep woods. Mimulus guttatus is its former name under which it can be found in older books.
You do have to look closely, but if you do, you can just make out tiny yellow flowers in the midst of the dense foliage.
Even though they resemble snapdragons, they are only distantly related, belonging to the same order, Lamiales. Order Lamiales includes Mint, Penstemon, Broomrape, and Figwort.