Nativity

Native plant Plants that occur naturally in a particular geographic area without direct or indirect human intervention.  For the purpose of the Taxonomic Data Center, a plant native to any area within the geographic range of the Checklist is considered to be native.     Introduced plant For the purpose of the Taxonomic Data Center, an introduced plant is a plant that has been moved or taken from its native range and released intentionally or unintentionally elsewhere through human activity. There are two types of introduced plants: Exotic and Adventive.    Exotic plant Plants from foreign areas (for the purpose of the Taxonomic Data Center, those that occur outside of North America north of Mexico) that have been released intentionally or unintentionally or have been disseminated or escaped as a result of human activity, and become established somewhere within the geographic range treated by the TDC.    A total of 3,802 exotic species, or 17.3% of the North American flora, is known to occur within the geographic area treated.  For all U.S. states, there is an average of approximately 610 exotic species per state, or an average of 21% of each state's flora.  For all Canadian provinces, there is an average of approximately 340 exotic species per province, or 21% of each provincial flora.  Thus, the average percentage of exotic species per U.S. state and Canadian province is identical.   Adventive plant  For the purpose of the Taxonomic Data Center, an adventive plant is a native plant that has been taken from its native range and released intentionally or unintentionally, or been disseminated elsewhere within the geographic area treated, through the direct or indirect influence of human activity.