(Bartonia paniculata iodandra)
Twining screwstem is a very inconspicuous annual or biennial that is probably a saprophytic mycotroph, that is, it gets most of its nutrients from a mutualistic fungus that feeds on rotting plant material. There is some speculation that it may be parasitic or hemiparasitic, obtaining nutrients from the roots of other plants through a fungal intermediary, but tests are lacking. It is found in southern New England in swamps, borrow pits and meadows.