Jeffersonia, a vernal plant of the natural order berberidacece, occurring in rich woods from western New York to Wisconsin and southward, named in honor of Thomas Jefferson. It is popularly known as twin-leaf, from its two-parted leaves, a character recognized in its specific name, J. diphylla; the long-petioled leaves arise in a tuft from the matted fibrous roots, and among them are naked flower stems, each terminated by a handsome white flower an inch in diameter, not unlike that of the bloodroot, and appearing in April and May. The calyx falls as the flower opens; petals and stamens eight; pistil single, which when ripe becomes a pear-shaped pod, which opens by a horizontal slit extending half way around it. In England the jeffersonia is valued as a plant for the spring border; well established clumps flower profusely, though the bloom is of short duration. Medicinal qualities have been attributed to the plant, which has in some localities the name of rheumatism root.