Distribution classifications used in The Compleat Botanica

Wetlands are transitional regions which vary between fully terrestrial and fully aquatic areas.  The water table in wetlands is usually at or near the surface.  Land covered by shallow water is also included in the definition.  In these regions the land periodically supports mostly hydrophytes, or the land is mostly saturated soil, or the land is non-soil and is saturated with water or covered by shallow water at some time during the growing season of each year.

The wetland indicator classification system represents the estimated probability of a species occurring in wetlands versus non-wetlands in a region of study.  It is defined in the "1996 National List of Vascular Plant Species That Occur in Wetlands", U.S. Fish & Wildlife Service, National Wetlands Inventory, Branch of Habitat Assessment. Branch of Habitat Assessment

The hierarchical wetland attribute classification system is defined in "Classification of wetlands and deepwater habitats of the United States", L.M. Cowardin, V. Carter, F. Golet, and E. LaRoe, U.S. Fish Wildlife Service, 1979. Full descriptions of each code is available at U.S. Fish Wildlife Service.

Threatened species are recognized as posing a potential loss to earth's biodiversity. "The United States Federal Endangered Species Act of 1973", U.S. Fish and Wildlife Service Endangered Species Act defines the terms "endangered", "threatened", and "rare".  State management agencies variously use additional terms including "sensitive" and "special concern" to further classify potentially threatened species.  This scheme is employed in the FESA status field.

UNEP World Conservation Monitoring Centre defines the classification system provided under the IUCN Red List field.  See the "The 1994 IUCN Red List Categories", UNEP World Conservation Monitoring Centre, IUCN Red List Categories.

The noxious weed rating system is based on various state management programs which rate plants based on their probability to be troublesome, aggressive, intrusive, detrimental, or destructive to agriculture, silviculture, or important native species, and difficult to control or eradicate.  The California Department of Food and Agriculture lists one such system.  For more details see California Department of Food and Agriculture.

An alternative ranking system for invasive weed management based on an analytic/numeric approach is the "Handbook for Ranking Exotic Plants for Management and Control", Ronald D. Hiebert and James Stubbendieck, U. S. Department of the Interior, National Park Service, Natural Resources Publication Office, 1993.  Handbook for Ranking Exotic Plants