Diario del proyecto Cacti of Ontario

Argus, G.W., C.J. Keddy, K.M. Pryor and D.J. White. (1982-1987). Atlas of the Rare Vascular Plants of Ontario, G.W. Argus & D.J. White (eds.). National Museum of Natural Sciences, Botany Division, Ottawa, Ont.

Beschel, R.E. (1967). The cactus at Kaladar. Blue Bill (Quarterly Bulletin of the Kingston Field Naturalists) 14(2): 11-12.

Benson, L. (1982). The Cacti of the United States and Canada. Stanford University Press, Stanford, CA, 1044 pp.

Britton, N. L., and Rose J. N. (1920). The Cactaceae. Vol 1. Carnegie Institute of Washington, Washington, DC., 236 pp.

Burgess, T.J.W. (1882). Notes From Canada. Botanical Gazette Vol. 7, Issue 8/9, pages 95-96.

Burgess, T.J.W. (1888-1889). The Lake Erie shore as a botanizing ground. Journal and Proceedings of the Hamilton Association 5: 41-59.

Consaul, L., S. Darbyshire, and A. Dugal. (1998). The status of the fragile prickly pear cactus (Opuntia fragilis) in Nepean, Ontario. Trail and Landscape 32: 175-181

Cota-Sánchez, J. H. (2002). Taxonomy, distribution, rarity status and uses of Canadian cacti. Haseltonia 9: 17-25.

Drezner, T. D. (2017). North and South: Morphological Variability in the Endangered Opuntia cespitosa in Canada and Variation with Environmental Conditions. Castanea, 82(1), 8–23. http://www.jstor.org/stable/26353871

Drezner, T. D. (2017). Shade, reproductive effort and growth of the endangered native cactus, Opuntia humifusa RAF. In Point Pelee National Park, Canada. The Journal of the Torrey Botanical Society 144(2), 179-190.

Drezner, T. D. (2019). Vegetation associations of the endangered Opuntia cespitosa (Prickly Pear, Cactaceae) and microsite variation in Point Pelee National Park, Ontario, Canada. Physical Geography. 42. 1-17.

Frego, K.A., and R.J. Staniforth. (1986). The Brittle Prickly-pear Cactus, Opuntia fragilis, in the boreal forest of southern Manitoba. Canadian Field-Naturalist 100(2): 229-236.

Frego, K.A., and R.J. Staniforth. (2000). Ecological History and Population Dynamics of a Disjunct Population of Brittle Prickly-pear Cactus, Opuntia fragilis (Cactaceae), in eastern Ontario. Canadian Field-Naturalist 114(1): 98-105.

Gorelick, R. (2015). Northern Range Limit of Opuntia fragilis and the Cactaceae is 56°N, Not 58°N. Madroño 62(2), 115-123, https://doi.org/10.3120/0024-9637-62.2.115

Hancock, K., S. Darbyshire, and R. Huntley. (2005). Canada's Kaladar cactus. British Cactus and Succulent Journal 23(2): 50-55.

Hyunh, M. (2023). Tracking the Dispersal of the Endangered Eastern Prickly Pear Cactus (Opuntia cespitosa) by Animal Vectors in Canada. Masters Thesis, York University, Toronto, ON, 119 pp.

Macoun, John, 1831-1920. (1922). Autobiography of John Macoun, M.A. : Canadian explorer and naturalist, assistant director and naturalist to the Geological Survey of Canada, 1831-1920. doi:http://dx.doi.org/10.14288/1.0343216

Macoun, J. (1883). Catalogue of Canadian Plants, Part I, Polypetalae. Dawson Brothers, Montreal. 192 pp.

Macoun, J. (1886). Catalogue of Canadian Plants, Part III, Apetalae. Dawson Brothers, Montreal. 395-623 pp.

Majure, L.C. and E. Ribbens. (2012). Chromosome Counts of Opuntia (Cactaceae), Prickly Pear Cacti, in The Midwestern United States and Environmental Factors Restricting the Distribution of Opuntia Fragilis. Haseltonia 2012(17), 58-65.

Majure, L.C., W.S. Judd, P.S. Soltis, and D.E. Soltis. (2017). Taxonomic revision of the Opuntia humifusa complex (Opuntieae: Cactaceae) of the eastern United States. Phytotaxa 290 (1): 001-065.

Moss, E. H. (1959). Flora of Alberta. University of Toronto Press, Toronto, ON, 546 pp.

Mottiar, Y., P. Chafe, and E. Ribbens. (2015). Imperfect Flowers of Opuntia fragilis in Kaladar, Ontario, Haseltonia 20: 22-25.

Oldham, M. & Brinker, S. (2009). Rare Vascular Plants of Ontario, Fourth Edition. DOI: 10.13140/RG.2.2.19537.84324.

Ontario Bureau of Mines (1896). Fifth Report of the Ontario Bureau of Mines; Ontario Bureau of Mines,
Annual Report, 1895, v.5, 51p.

Parfitt, B. D. (1991). Biosystematics of the Opuntia polyacantha complex (Cactaceae) of western North America. Ph.D. Dissertation. Arizona State University, Tempe, AZ, 115 pp.

Parks Canada Agency. (2023). Report on the Progress of Recovery Strategy Implementation for the Eastern Prickly Pear Cactus (Opuntia humifusa) in Canada (2018 – 2022). Species at Risk Act Recovery Strategy Report Series. Parks Canada Agency, Ottawa. 9 pp.

Reznicek, A. A. (1982). The cactus in southwestern Ontario. Ont. Field. Biol. 36: 35-38

Reznicek, A. & Catling, P. (1989). Flora of Long Point, Regional Municipality of Haldimand-Norfolk, Ontario. 28. 99-175.

Ribbens, E. (2008). Opuntia fragilis: taxonomy, distribution, and ecology. Haseltonia 14: 94-110.

Staniforth, J., Cody, W.J., and Frego, K.A. (2002). Bill Dore's notes on the Kaladar cactus (Opuntia fragilis). Canadian Field-Naturalist 116(4): 547-550.