Bartonia paniculata

Bartonia paniculata, commonly known as twining screwstem, is a saprophytic, annual or biennial species that grows in acidic, sandy-peaty wetlands.

Distribution

Bartonia paniculata is the northernmost-ranging species in the genus Bartonia. It is found along the Atlantic coastal plain; its widespread range crosses 29 American states and five Canadian provinces, and overlaps with that of Bartonia virginica. The subspecies texana is found in eastern Texas and northeastern Louisiana; it was previously identified as Bartonia texana.

Conservation

Twining screwstem is legally protected in the state of Michigan as a threatened species.
Populations of the subspecies texana have declined by 50% over the past 57 years. It is found within the baygalls of the coastal plain forests of southeastern Texas. As the baygalls have become rarer as a plant community, the texana subpopulation has also declined.