This is as widespread in eastern states as cephalophora, but it tends to occur in more open, disturbed or stressed habitats on more damp fertile soils. It is locally abundant in seasonally wet, clayey or compacted low mowed areas, from remnants of western grasslands to fescue fields, lawns and ditches in the Bluegrass (together with much Juncus dudleyi at some sites). C. leavenworthii is often confused with cephalophora. It can be diagnosed primarily by its perigynia (FNA 23), which have broadly ovate (versus elliptic) bodies widest at 25-40% from base (versus 40-55%), with distal margins smooth or serrulate (versus serrulate). Also, the beaks are shorter (0.3-0.8 mm versus 0.7-1.1 mm), with shorter teeth (0.1-0.3 mm versus 0.3-0.5 mm). Leaves tend to be narrower, the widest per plant 1.1-4 mm (versus 1.9-5 mm); and culms tend to be narrower at base, 1-2.5 mm (versus 2-3.5 mm). See also notes under mesochorea, which tends to occur on more fertile and more mesic sites (with less dry and wet extremes).