This early spring native buttercup has the typical 5 glossy yellow petals and numerous stamens that are typical of the buttercup family. To identify most of the 20-30 buttercups in this part of the world it is necessary to look at the stems and leaves. The swamp buttercup is highly variable and some botanists want to divide it into 3 or 4 different species. Others consider it a subspecies of the hispid buttercup (Ranunculus hispidus). Generally, the swamp buttercup has a weak, hollow, smooth stem that often reclines near the ground. It can be one to three feet long.

The leaves are in three segments each with a short stalk. Each segment is deeply lobed. This species also prefers a moist habitat, either in open woods, meadows or thickets. The flowers are of moderate size - about one inch in diameter. The base of each petal is pale greenish-yellow with about 5 fine lines functioning as nectar guides; the remainder of the petal is bright yellow and shiny.