Cronquist, A. J. 1994. Vascular plants of the intermountain west, U.S.A. 5: 1–496. In A. J. Cronquist, A. H. Holmgren, N. H. Holmgren, J. L. Reveal & P. K. Holmgren (eds.) Intermount. Fl.. Hafner Pub. Co., New York.