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

References

• Britton, N L., & Brown A. (1913). An Illustrated Flora of the Northern United States, Canada And The British Possessions. 3,
• 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.
• Fernald, M. 1950. Manual (ed. 8) i–lxiv, 1–1632. American Book Co., New York.
• Flann C. (ed) (2013). GCC: Global Compositae Checklist (version 3 (Beta), Feb 2012). In: Species 2000 & ITIS Catalogue of Life, 11th March 2013 (Roskov Y., Kunze T., Paglinawan L., Orrell T., Nicolson D., Culham A., Bailly N., Kirk P., Bourgoin T., Baillargeon G., Hernandez F., De Wever A., eds). Digital resource at www.catalogueoflife.org/col/. Species 2000: Reading, UK.
• Flora of North America Editorial Committee, e. 2006. Magnoliophyta: Asteridae, part 8: Asteraceae, part 3. 21: i–xxii + 1–616. In Fl. N. Amer. Oxford University Press, New York.
• 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.
• Gutierrez, A. B., & Herz W. (1990). Ambrosanolides and other constituents of two rudbeckia species.. Planta Med. . 56(3), 295-297.
• Hilty, J. Editor. 2013. Illinois Wildflowers. World Wide Web electronic publication. flowervisitors.info, version 04/2013.
  See: Botanical Terminology and Line Drawings,  Ecological Terminology,  Website Description,  Links to Other Websites,  Reference Materials
• Hilty, J. Editor. 2013. Insect Visitors of Illinois Wildflowers.   World Wide Web electronic publication. illinoiswildflowers.info, version (05/2013)  
  See:   Abbreviations for Insect Activities,   Abbreviations for Scientific Observers,   References for behavioral observations
• Image metadata at Bioimages (http://bioimages.vanderbilt.edu/)
• Koch, M F. (1930). Studies in the Anatomy and Morphology of the Composite Flower II. The Corollas of the Heliantheae and Mutisieae. American Journal of Botany. 17(10), 995-1010.
• Moerman, D. E. (1998). Native American Ethnobotany. Portland, OR: Timber Press, Inc..
• 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.
• Samuel B. Jones, J.. (1970). Chromosome Numbers in Compositae. Bulletin of the Torrey Botanical Club. 97(No 3), 168-171.
• Scoggan, H. J. 1979. Dicotyledoneae (Loasaceae to Compositae). Part 4. 1117–1711 pp. In Fl. Canada. National Museums of Canada, Ottawa.
• Small, J. K. 1933. Man. S.E. Fl. i–xxii, 1–1554. Published by the Author, New York.
• USDA, NRCS. (2010). The PLANTS Database.
• Urbatsch, L. E., & Cox P. B. (2006). Rudbeckia. (Editorial Committee of Flora North America, Ed.).Flora of North America. 21,
• Voss, E. G. 1996. Michigan Flora, Part III: Dicots (Pyrolaceae-Compositae). Cranbrook Inst. of Science, Ann Arbor.
• Wunderlin, R. P. 1998. Guide Vasc. Pl. Florida i–x, 1–806. University Press of Florida, Gainseville.