Publication: Fl. Bor.-Amer. 2: 221. 1839.
selected vouchers: WTU
Notes: This taxon keys to C. rostrata in H&C.
FNA23: "Carex utriculata is abundant and variable and is often a dominant of wetlands in subarctic, boreal, and north-temperate wetlands. American authors usually treat the taxon as part of the variation of Carex rostrata, but it is a very different plant with a quite different leaf shape in cross section and very different leaf anatomy. Plants from the western and northern portions of the range often have perigynia strongly tinged with purple, though that coloration can also occur rarely elsewhere.
Rarely, Carex utriculata forms hybrids with C. exsiccata, C. hystericina, C. lacustris, C. pellita, C. rostrata, C. rotundata, C. saxatilis, and C. vesicaria. The hybrids are sterile and intemediate in morphology."