New York Natural Heritage Program
Twin-leaf
Jeffersonia diphylla (L.) Pers.
Dicots
Jeffersonia diphylla in flower Stephen M. Young
Family: Barberry Family (Berberidaceae)

State Protection: Threatened
listed species are those with: 1) 6 to fewer than 20 extant sites, or 2) 1,000 to fewer than 3,000 individuals, or 3) restricted to not less than 4 or more than 7 U.S.G.S. 7 minute topographical maps, or 4) listed as threatened by U.S. Department of Interior.

Federal Protection: Not Listed

State Rarity Rank: S2
A State Rarity Rank of S2 means: This plant is threatened/imperiled in New York because of rarity (typically 6-20 populations or few remaining individuals) or is vulnerable to extirpation from New York due to biological factors.

Global Rarity Rank: G5
A Global Rarity Rank of G5 means: This species is demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.


Did you know?
Twinleaf is one of only two species in the genus Jeffersonia. The other species, Jeffersonia dubia, grows in Mongolia. Benjamin Barton, a Philadelphia botanist of the 18th-century, was so impressed by Thomas Jefferson's knowledge of natural history he named this plants after him. Twinleaf is said to have been used for treating rheumatism but it can be poisonous if not prepared correctly.

State Ranking Justification [-]
There are 15 populations in the state with two thirds of them containing hundreds to thousands of plants. There are 23 historical populations, many of which have not been searched, and more populations are expected to be found. While the short term trends are stable, logging and invasion by exotic species may negatively affect long term trends.

Short-term Trends [-]

Long-term Trends [-]