Culms 51-129 cm. Ligules 0.7-2.9 mm; blades 7-14 mm wide, linear to lanceolate, abaxial surfaces smooth, adaxial surfaces sometimes densely pilose basally, otherwise scabrous. Panicles 16-34 cm, dense; lower branches 2-5 cm, divergent. Callus hairs 8-12 mm; glumes 2.7-4.1 mm; lower lemmas 2.5-3.9 mm, membranous, glume like; upper lemmas 1.4-2.4 mm, completely surrounding the ovary; stamens 1, filaments dilated at the base; anthers 1.3-2.3 mm, yellow to orange; styles 0.9-2.4 mm; stigmas 2.1-4 mm, purple to brown. 2n = 20.
Imperata brevifolia is native to wet or moist sites in the southwestern deserts from California, Nevada, and Utah to western Texas. Many of the populations that were used in developing the map no longer exist, but several post-1990 collections have been made in San Bernardino, Sonoma, Fresnoa, Santa Barbara, Butte, and Kern Counties of California. It also persists in the Grand Canyon National Park. Most collections from Nevada, Utah, and Texas were made before 1945, in sites that are now used for housing or agriculture.
Imperata brevifolia was listed as a noxious weed by the state of California. The reason for the listing is not clear; it may have stemmed from confusion of this native species with one of the introduced weedy species. In September 2003, Dr. Fred Hrusa succeeded in persuading the California authorities that Imperata brevifolia should be taken off the state's noxious weed list.