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

References

• Ames, O. & D. S. Correll. 1952. Orchids of Guatemala. Fieldiana, Bot. 26(1): i–xiii, 1–395.
• Anonymous. 1986. List-Based Rec., Soil Conserv. Serv., U.S.D.A. Database of the U.S.D.A., Beltsville.
• Breedlove, D. E. 1986. Flora de Chiapas. Listados Floríst. México 4: i–v, 1–246.
• CONABIO. 2009. Catálogo taxonómico de especies de México. 1. In Capital Nat. México. CONABIO, Mexico City.
• Correll, D. S. & M. C. Johnston. 1970. Man. Vasc. Pl. Texas i–xv, 1–1881. The University of Texas at Dallas, Richardson.
• Dodson, C. H. 1992. Checklist of the Orchids of the Western Hemisphere. draft:.
• Engelm. & A.Gray. 1845. In: Boston J. Nat. Hist. 5: 236
• Felder, D.L. and D.K. Camp (eds.), Gulf of Mexico–Origins, Waters, and Biota. Biodiversity. Texas A&M Press, College Station, Texas.
• Fernald, M. 1950. Manual (ed. 8) i–lxiv, 1–1632. American Book Co., New York.
• Flora of North America Editorial Committee, e. 2002. Magnoliophyta: Liliidae: Liliales and Orchidales. 26: i–xxvi, 1–723. In Fl. N. Amer. Oxford University Press, New York.
• Gleason, H. A. & A. J. Cronquist. 1968. The Pteridophytoa, Gymnospermae and Monocotyledoneae. 1: 1–482. In H. A. Gleason Ill. Fl. N. U.S. (ed. 3). New York Botanical Garden, 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.
• Godfrey, R. K. & J. W. Wooten. 1979. Aquatic Wetland Pl. S.E. U.S. Monocot. 1–712. The University of Georgia Press, Athens.
• Govaerts R. (ed). For a full list of reviewers see: http://apps.kew.org/wcsp/compilersReviewers.do (2013). WCSP: World Checklist of Selected Plant Families (version Oct 2011). 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.
• Great Plains Flora Association. 1986. Fl. Great Plains i–vii, 1–1392. University Press of Kansas, Lawrence.
• 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/)
• Long, R. W. & O. K. Lakela. 1971. Fl. Trop. Florida i–xvii, 1–962. University of Miami Press, Coral Cables.
• 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.
• Scoggan, H. J. 1978 [1979]. Pteridophyta, Gymnospermae, Monocotyledoneae. 2: 93–545. 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.
• Type collection: Small, J. K. 1898. Bull. Torrey Bot. Club. 25: 610.
• Voss, E. G. 1972. Gymnosperms and Monocots. i–xv, 1–488. In Michigan Fl. Cranbrook Institute of Science, Bloomfield Hills, Michigan.
• WoRMS (2013). Spiranthes vernalis Engelmann & A. Gray, 1845. Accessed through: Tunnel, W.; Moretzsohn, F. (2013) Gulf of Mexico register of marine species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=418800 on 2013-03-02
• Wunderlin, R. P. 1998. Guide Vasc. Pl. Florida i–x, 1–806. University Press of Florida, Gainseville.