The following bibliography has been generated by bringing together all references provided by our content partners. There may be duplication.


  • 1996. database, The PLANTS Database
  • 1996. database, NODC Taxonomic Code
  • 2000. database, The PLANTS Database
  • 2011. Lamiales of North America Update
  • CONABIO. 2009. Catálogo taxonómico de especies de México. 1. In Capital Nat. México. CONABIO, Mexico City.
  • Fernald, M. 1950. Manual (ed. 8) i–lxiv, 1–1632. American Book Co., New York.
  • Flora of the Southeastern United States 1060, 1337. 1903. (22 Jul 1903) (Fl. S.E. U.S.)
  • Gleason, H. A. & A.J. Cronquist. 1991. Man. Vasc. Pl. N.E. U.S. (ed. 2) i–910. New York Botanical Garden, Bronx.
  • Gleason, H. A. 1968. The Sympetalous Dicotyledoneae. vol. 3. 596 pp. In H. A. Gleason Ill. Fl. N. U.S. (ed. 3). New York Botanical Garden, New York.
  • Great Plains Flora Association. 1986. Fl. Great Plains i–vii, 1–1392. University Press of Kansas, Lawrence.
  • Hilty, J. Editor. 2015. Insect Visitors of Illinois Wildflowers.  World Wide Web electronic publication., version (09/2015) 
    See:   Abbreviations for Insect ActivitiesAbbreviations for Scientific ObserversReferences for behavioral observations
  • Isotype: Pennell, F. W. 1922. Proc. Acad. Nat. Sci. Philadelphia. 73: 494.
  • Isotype: Pennell, F. W. 1935. Acad. Nat. Sci. Philadelphia Monogr. 1: 227.
  • Orrell T. (custodian) (2015). ITIS Regional: The Integrated Taxonomic Information System (version Dec 2014). In: Species 2000 & ITIS Catalogue of Life, 26th August 2015 (Roskov Y., Abucay L., Orrell T., Nicolson D., Kunze T., Flann C., Bailly N., Kirk P., Bourgoin T., DeWalt R.E., Decock W., De Wever A., eds). Digital resource at Species 2000: Naturalis, Leiden, the Netherlands. ISSN 2405-8858.
  • Radford, A. E., H. E. Ahles & C. R. Bell. 1968. Man. Vasc. Fl. Carolinas i–lxi, 1–1183. University of North Carolina Press, Chapel Hill.
  • Small, J. K. 1933. Man. S.E. Fl. i–xxii, 1–1554. Published by the Author, New York.
  • Voss, E. G. 1996. Michigan Flora, Part III: Dicots (Pyrolaceae-Compositae). Cranbrook Inst. of Science, Ann Arbor.


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