Publication: Sp. Pl. 2: 976. 1753.
selected vouchers: WTU
Notes: FNA23: "Carex saxatilis is highly variable in North America. Plants from western North America, often named C. physocarpa, tend to be robust with long peduncles on the pistillate spikes, wide leaves, and large perigynia. These characters decrease in size eastward across North America with successively smaller plants usually referred to as C. saxatilis and C. miliaris. This weak east/west cline is confounded by large amounts of variation within small geographic areas and phenotypic plasticity. B. A. Ford et al. (1991) and B. A. Ford and P. W. Ball (1992) have demonstrated that these segregates represent elements in a continuum rather than discrete taxa.
Hybrids between Carex saxatilis and C. vesicaria (= C. ×stenolepis Lessing; = C. ×mainensis Porter ex Britton) and C. saxatilis and C. utriculata (= C. ×physocarpoides Lepage) have been found in North America (B. A. Ford et al. 1993). These hybrids are infrequent, largely sterile, and intermediate in morphology between the two parents."