Literature
The following references relate mainly to native violets of the Great Plains and eastern North America but also include studies conducted in North America on introduced violets. Some references to western North American taxa are included but the list is not comprehensive.
Alexander, E. J. 1963. Violaceae. In Gleason, H. A., The new Britton and Brown illustrated flora of the northeastern United States and adjacent Canada. Hafner Publishing Co., Inc., New York, NY. 552-567.
Anderson, E. 1954. An analysis of introgression in a population of stemless white violets. Annals of the Missouri Botanical Garden 41: 263-269.
Anderson, E. 1949. Introgressive hybridization. John Wiley & Sons, Inc., New York , NY.
Anderson, P. D. 1983. The dynamics and longevity of Viola fimbriatula seeds in the soil (nitrate). Ph.D. dissertation. Harvard University, Cambridge, MA.
Awl, D. J., L. R. Pounds, B. A. Rosensteel, A. L. King, and P. A. Hamlett. 1996. Survey of protected vascular plants on the Oak Ridge Reservation, Oak Ridge, Tennessee. Unpublished report, Environmental Restoration Division, Oak Ridge, TN.
Baker, M. S. 1935. Studies in western violets-I. Sections Chamaemelanium and Nomimium. Madroño 3: 51-57.
Baker, M. S. 1936. Studies in western violets-II. New species and varieties. Madroño 3: 232-239.
Baker, M. S. 1940. Studies in western violets-III. Madroño 5: 218-231.
Baker, M. S. 1949a. Studies in western violets, VI. Madroño 10: 110-128.
Baker, M. S. 1949b. Studies in western violets-IV. Leaflets of Western Botany 5: 141-147.
Baker, M. S. 1949c. Studies in western violets-V. Leaflets of Western Botany 5: 173-177.
Baker, M. S. 1953. Studies in western violets, VII. Madroño 12: 8-18.
Baker, M. S. 1957. Studies in western violets-VIII. The Nuttalianae [sic!] continued. Brittonia 9: 217-230.
Baldwin, B. G., and W. L. Wagner. 2010. Hawaiian angiosperm radiations of North American origin. Annals of Botany 105: 849-879.
Ballard Jr., H. E. 1985. Viola epipsila new to Michigan and the eastern United States. Michigan Botanist 24: 131-134.
Ballard Jr., H. E. 1987. Violaceae. Argus, G. and K. Pryer (eds.). Atlas of Ontario rare plants, [10]. National Museum of Natural Sciences, Ottawa, Canada.
Ballard Jr., H. E. 1990a. Hybrids among three caulescent violets, with special reference to Michigan. Michigan Botanist 29: 43-54.
Ballard Jr., H. E. 1990b ['1989']. Viola ×eclipes, a new hybrid violet. Michigan Botanist 28: 216-219.
Ballard Jr., H. E. 1992. Systematics of Viola section Viola in North America north of Mexico. M.S. thesis. Central Michigan University, Mount Pleasant, MI.
Ballard Jr., H. E. 1993. Three new rostrate violet hybrids from Appalachia. Castanea 58: 1-9.
Ballard Jr., H. E. 1995 ["1994"]. Violets of Michigan. Michigan Botanist 33: 131-199.
Ballard Jr., H. E. 1996. Phylogenetic relationships and infrageneric groups in Viola (Violaceae) based on morphology, chromosome numbers, natural hybridization, and Internal Transcribed Spacer (ITS) sequences. Ph.D. dissertation. University of Wisconsin, Madison, WI.
Ballard Jr., H. E. 2000. Violaceae. In Rhoads, A. (ed.). Flora of Pennsylvania. University of Pennsylvania Press, Philadelphia, PA. 700-710.
Ballard Jr., H. E. 2012. The LEAFY gene illuminates species relationships, allopolyploid speciation and biogeography in the North American Viola canadensis (Violaceae) complex. Botany 2012, Columbus, OH.
Ballard Jr., H. E. 2013. Violaceae. In Yatskievych, G., Flora of Missouri. Missouri Botanical Garden Press, St. Louis, MO. 1218-1243.
Ballard Jr., H. E. 2022. Violaceae. Naczi, R.F.C. (ed.), New Manual of Vascular Plants of Northeastern United States and Adjacent Canada, New York Botanical Garden Press, Bronx, NY, accepted pending revision.
Ballard Jr., H. E., R. N. Burwell, and S. L. Lockhart. 2020. Violaceae: Typifications and clarifications of names. In Weakley, A. S., D. B. Poindexter, H. C. Medford, B. A. Sorrie, C. A. McCormick, E. L. Bridges, S. L. Orzell, K. A. Bradley, H. E. Ballard, Jr., R. N. Burwell, S. L. Lockhart, and A. R. Franck. Studies in the vascular flora of the southeastern United States. VI. Journal of the Botanical Research Institute of Texas 14(2): 217-229.
Ballard Jr., H. E., D. A. Casamatta, M. M. Hall, R. A. McCauley, M. C. Segovia-Salcedo, and R. G. Verb. 2001. Phenetic analysis shows conspecificity between Hispaniolan Viola domingensis Urban and North American Viola macloskeyi sensu lato (Violaceae). Brittonia 53: 122-136.
Ballard, H. E., A. C. Cortes-Palomec, M. Feng, Y. Wang, and S. Wyatt. 2011. The chasmogamous/cleistogamous mixed breeding system, a widespread and evolutionarily successful reproductive strategy in angiosperms. Thangadurai, D., C. A. Busso, and M. Hijri (eds.), Frontiers in biodiversity studies, 16-41. Bioscience Publications, Agrobios, India.
Ballard Jr., H. E., M. D. Devine, and K. J. Sytsma. 1997. Centrifugal allopatric speciation in the Viola canadensis complex (Violaceae) based on Internal Transcribed Spacer DNA sequences.American Institute of Biological Sciences, Montreal, Quebec.
Ballard Jr., H. E., and S. C. Gawler. 1994. Distribution, habitat and conservation of Viola novae-angliae. Michigan Botanist 33: 35-52.
Ballard Jr., H. E., J. Paula Souza, and G. A. Wahlert. 2014. Violaceae. Kubitzki, K. (ed.), The families and genera of vascular plants, 303-322. Springer-Verlag, Berlin, Germany.
Ballard, Jr., H. E., B. A. Sorrie, and A. S. Weakley. 2020. Violaceae. In: Weakley, A. S. Flora of the southeastern United States. University of North Carolina, Chapel Hill, NC.: 862-878.[https://doi.org/10.1007/s12225-020-9866-6].
Ballard Jr., H. E., K. J. Sytsma, and R. R. Kowal. 1999. Shrinking the violets: Phylogenetic relationships of infrageneric groups in Viola (Violaceae) based on internal transcribed spacer DNA sequences. Systematic Botany 23: 439-458.
Ballard Jr., H. E., and K. J. Sytsma. 2000. Evolution and biogeography of the woody Hawaiian violets (Viola, Violaceae): Arctic origins, herbaceous ancestry and bird dispersal. Evolution 54: 1521-1532.
Ballard Jr., H. E., and D. E. Wujek. 1994. Evidence for the recognition of Viola appalachiensis. Systematic Botany 19: 523-538.
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Baskin, J. M., and C. C. Baskin. 1970. New county records for the cedar glade endemic Viola egglestonii. Journal of the Tennessee Academy of Science 45: 60.
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Brainerd, E. 1904b. Notes on New England violets. Rhodora 6: 8-17.
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Brainerd, E. 1906a. How stems and stolons disappear in Viola. Bulletin of the Vermont Botanical Club 1: 11.
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Brainerd, E. 1909. Another hybrid between a white and a blue violet. Rhodora 11: 115-116.
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Brainerd, E. 1913b. Is Viola arenaria indigenous to North America? Rhodora 15: 106-111, plate 104.
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