Very similar to ladysthumb (Persicaria maculosa) but without the dark blotch on the leaf and the upper margin of the sheath without cilia. South Dakota Weeds uses the common name of `tanweed` and the scientific name of Polygonum muhlenbergia, but neither name is used elsewhere. The form formerly referred to as Polygonum bicorne is always pink flowered and has either the stamens or styles (but not both) sticking out of the flower.