Achnatherum aridum is a species of grass known by the common name Mormon needlegrass. It is native to the southwestern United States from the Mojave Desert in California east to Colorado and New Mexico. Achnatherum aridum is a resident of high desert scrub and woodland habitat at some elevation. It is a tuft-forming perennial bunchgrass without rhizomes. The bunches of stems reach a maximum height of around 85 centimetres (33 in). The inflorescence is a panicle often partly enfolded in the narrow sheath of the uppermost leaf. The spikelets have hairlike awns 4-8 centimetres (1. 6-3. 1 in) long. Achnatherum aridum is a resident of high desert scrub and woodland habitat at some elevation. It is a tuft-forming perennial bunchgrass without rhizomes. The bunches of stems reach a maximum height of around 85 centimetres (33 in). The inflorescence is a panicle often partly enfolded in the narrow sheath of the uppermost leaf. The spikelets have hairlike awns 4-8 centimetres (1