This plant belongs to the purpled-flowered loosestrife family (Lythraceae). Valley redstem is usually found in wetland areas and is a National Wetland Indicator species. The opposite, linear leaves are smooth, somewhat fleshy, and often distended at the base. The pink flowers grow on a short stalk in the leaf axis and have four rounded petals. The plant can grow up to 1½ feet tall. The genus is named after a 17th century German botanist, Paul Ammann.