This east North American species (2n = 46) is distinct but close to stipata (2n = 48, 52), which occurs in similar habitat (or perhaps less nutrient-rich) but across much of North America and East Asia. C. laevivaginata differs in the adaxial side of its leaf sheaths, which are yellowish-thickened at the apex (versus thin and friable) and flat below the apex (versus rugose-puckered). Also, leaf blades are papillose around stomata (versus not), when viewed at x 25 (FNA 23). Spikes are generally smaller: ca. 3-6 x 1.5 cm (versus 5-15 x 4 cm), but perigynia are similar or just slightly snaller on average (FNA 23).