Regional Wetlands Indicator (RWI) Classification
This catalog includes the Regional Wetland Indicator (Region 6, Oklahoma and Texas) status for each species. The RWI status for each species was obtained from the wetlands section of the PLANTS Database maintained by the USDA Natural Resources Conservation Service.
Obligate Wetland (OBL) - Occurs almost always (estimated probability >99%) under natural conditions in wetlands.
Facultative Wetland (FACW) - Usually occurs in wetlands (estimated probability 67-99%), but occasionally found in nonwetlands.
Facultative (FAC) - Equally likely to occur in wetlands or nonwetlands (estimated probability 34-66%).
Facultative Upland (FACU) - Usually occurs in nonwetlands (estimated probability 67-99%), but occasionally found in wetlands (estimated probability 1-33%).
Obligate Upland (UPL) - Occurs in wetlands in another region, but occurs almost always (estimated probability >99%) in the upland under natural conditions in Region 6. In this catalog, a blank space, "none", or "NI" in the NWI section is usually equivalent to UPL.
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Last update: 11/2/98
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