Category A--Plant species that are invading and disrupting native plant communities in Missouri.
A-1--Widespread, essentially in all counties of Missouri
A-2--Regional species invasive in more than 10 Missouri counties.
A-3--Regional species invasive in 10 or fewer Missouri counties.

Category B--Plant species that are occasional invaders with low levels of impact on native Missouri plant communities, or species which are invading and disrupting the native plant communities of other states, in habitats similar to those found in Missouri.

Category C--Plant species that have the capacity to invade native plant communities along disturbance corridors, or to spread from stands in disturbed sites into undisturbed areas, but which seem to principally spread and remain in disturbed corridors.

Category D--Plant species for which current information does not adequately describe distribution or nature of threat to native plant communities.

Category E--Plant species that, after review of status, do not appear to pose a significant threat to native plant communities.

Exotic: before European contact, not native to the area currently designated as Missouri.
Invasive: entering natural communities, potentially displacing native vegetation.

The Missouri Exotic Pest Plant Council is currently rating exotic invasives according to the threat they pose toward natural ecosystems. For an explantation of the rating categories, and the complete list of potential invasive plants of Missouri click here.