Jeffersonia

Jeffersonia, also known as twinleaf or rheumatism root, is a small genus of herbaceous perennial plants in the family Berberidaceae. They are uncommon spring wildflowers and grow in limestone soils of rich deciduous forests. Jeffersonia was named for United States President Thomas Jefferson by his contemporary Benjamin Smith Barton. This genus was formerly grouped in genus Podophyllum. Twinleaf is protected by state laws as a threatened or endangered plant in Georgia, Iowa, New York, and New Jersey.

== Description == Jeffersonia diphylla has leaves and flowers that are smooth and emerge directly from the rhizome. The leaves are divided into two leaflets which are half-ovate in shape with entire or shallowly toothed margins. It has showy white flowers with four sepals, eight petals, eight stamens, and a singly pistil; the flower resembles bloodroot flowers. The short-lived flower appears in April or May before the forest canopy appears (see spring ephemeral). The fruit is a green pear-shaped capsule with a hinged top. The characteristic leaves are large and nearly divided in half, giving rise to its common name, twinleaf. It rarely grows taller than . As with other deciduous forest plants, the seeds are dispersed by ants, a process known as myrmecochory.