Krigia is diverse and limited to North America. On molecular evidence, it stands apart from other clades of Cichorieae and is best placed as a monotypic subtribe (J. Lee et al. 2003; Lee and B. G. Baldwin 2004). Early studies classified the pappose and epappose species as different genera. A unified view of the genus was taken by L. H. Shinners (1947), and this has been supported by recent morphologic and molecular studies (K. J. Kim and T. J. Mabry 1991; Kim and B. L. Turner 1992; Kim et al. 1992b, 1992c; Kim and R. K. Jansen 1994). The most common base number is x = 5, with lower and higher numbers having arisen through dysploidy, autoploidy, and both ancient and recent alloploidy (K. L. Chambers 1965, 2004; A. S. Tomb et al. 1978; C. C. Chinnappa 1981; Kim and Turner).