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DistributionMore info for the terms: cover, natural
Dalmatian toadflax is a native of the Mediterranean region from Yugoslavia to Iran . Yellow toadflax is native to the steppes of southeastern Europe and southwestern Asia . Both species have been cultivated as ornamentals for centuries and are widely distributed throughout the world [1,95,114].
It has been suggested that Dalmatian toadflax was introduced to North America as an ornamental in the late 1800s; however, the earliest authentic specimen was collected in California in 1920 [1,114]. Yellow toadflax was introduced to New England in the late 1600s as an ornamental and medicinal plant and continues to be sold in nurseries and seed catalogs. For example, Gutknecht  lists "Linaria vulgaris (common toadflax or butter-and-eggs)" as a plant that is well suited for xeriscaping. The spread of toadflax was facilitated by its use as an ornamental, medicinal, magical, and dye plant, although accidental introduction and distribution along roads and railway corridors, or in crop seed, baled hay, ship ballast, and clothing likely increased its spread [57,95].
Toadflax occurs throughout the continental U.S. and in almost every Canadian province [47,110]. Yellow toadflax is most common in northeastern North America, and localized in other parts of the continent, particularly the western Canadian provinces . The northern limits of yellow toadflax's North American range are approximately 55Â° N to 65Â° N . The latitudinal range of Dalmatian toadflax in North America is from about 33Â° N to about 56Â° N, as compared to a range of about 35Â° N to 47Â° N in Eurasia . Dalmatian toadflax is most common in western North America, especially in California, Oregon, Washington, Idaho, Montana, Wyoming, Alberta, and British Columbia [11,57,77], and it is spreading in the Southwest. For example, it is estimated to have invaded 200,000 acres (80,000 ha) on the Coconino National Forest in northern Arizona as of 2001 .
Toadflax is most commonly found in cultivated fields, roadsides, railways, "waste areas", clearcuts, overgrazed pastures and rangeland, and in plant communities that are typically open or disturbed [6,57]. Neither species occurs as frequently in intact wildlands and natural areas.
The following lists include some ecosystems, habitats, and forest and range cover types in which toadflax is known or thought to be invasive, as well as several that may be invaded by toadflax following disturbances in which vegetation is killed and/or removed (e.g. cultivation, logging, fire, grazing, herbicide application, flooding). These lists are speculative and not exhaustive. More information is needed regarding incidents and examples of particular ecosystems and plant communities where toadflax is invasive.