Swertia caroliniensis or Frasera caroliniensis?

ABSTRACT
Most modern state and regional floras for eastern North America use the binomial <em>Swertia caroliniensis</em> (Walt.) Kuntze, rather than <em>Frasera caroliniensis</em> Walt., for the American Columbo. Cytological studies by Rork (1949) and cytological, morphological and anatomical studies by Post (1956) provide strong evidence that <em>Frasera</em> Walt. is a distinct genus from <em>Swertia</em> L. Recent chemical studies on <em>F. caroliniensis</em> by Stout and Balkenhol (1969) further support the separation of the two genera. Thus, the correct binomial for the eastern American Columbo is <em>Frasera caroliniensis</em> Walt.