This is a widespread, variable northern and western species, but probably somewhat adventive to the southeast; 2n = 48 to 68 (FNA 23). It appears similar to the east-central molestiformis, the largely midwestern molesta, the largely south-central festucacea, and the southeastern reniformis, There has been considerable confusion among these species, and brevior may have been generally overlooked in Ky. Most records are from relatively dry soils (at least in the summer). C. brevior may be closest to molestiformis (FNA 23). Perigynia tend to be shorter (mostly 3.4-4.8 mm versus 4-5.4 mm). Perigynium bodies are almost veinless (versus strongly veined), suborbicular with l/w mostly 0.9-1.1 (versus suborbicular to elliptic with l/w mostly 1-1.6), 2-3.2 mm long (versus 2.7-4 mm). Pistillate scales are mostly acute, 0-0.7 mm shorter than each perigynium (versus mostly obtuse, 0.7-1.7 mm shorter). Inflorescences tend to be less congested but with more spikes (3-7 versus 2-5), and the terminal one does not have the distinctively prominent staminate base of molestiformis.