Basis for Former Listing
Carex crus-corvi is distributed along drainages of the Mississippi River and also along the southeast coastal plain (Standley 2002). Range-wide it is found in wetland habitats and along floodplains. Carex crus-corvi tends to be rare on the edges of its range (to the north, west, and east) and is considered critically imperiled in Wisconsin, Nebraska, Ontario, Virginia, and North Carolina (NatureServe 2011). Minnesota represents the northwestern-most limit of the species' range (Wheeler 1981).
Carex crus-corvi has been collected only twice in Minnesota; first by J. H. Sandberg in Goodhue County in 1885 (not depicted on map) and later by Fassett and Hotchkiss in Wabasha County in 1926. Both of these collections were from bottomlands in the Mississippi River valley. Carex crus-corvi was listed as a special concern species in 1996.
Basis for Delisting
When C. crus-corvi was designated a special concern species, some potential habitat still remained to be surveyed. Despite botanical inventory work in Goodhue and Wabasha counties and some efforts to specifically search for this species, no remnant populations of C. crus-corvi have been discovered. The loss of this species in Minnesota may be the result of the drastic alteration of its habitat caused by the extensive lock and dam system constructed on the Mississippi River in the 1930s. Carex crus-corvi is now considered extirpated from Minnesota. Therefore, special concern status is no longer necessary and the species was delisted in 2013.