Scientific Name
Pascopyrum smithii (Rydb.) Á. Löve (Synonyms: Agropyron smithii; Elymus smithii)
Common Name(s)
Western wheatgrass
Tribe / Family Name
Triticeae
Flowering Period
June to August
Symbol
PASM
Description
Western wheatgrass is a native cool-season perennial rhizomatous grass that reproduces from seeds and rhizomes. Culms range from 20–100 cm in height. Its inflorescence is a stiff, erect spike 5–17 cm long and not shattering at maturity. Spikelets are usually 12–26 mm long, closely imbricate, appressed along the main rachis, 1 per rachis node (sometimes 2 per node), 2- to 12-flowered, and unawned or awned (the lemma awns 0.5–5 mm long). Auricles are short (up to 1 mm long) and often purple. Ligules are inconspicuous (mostly about 0.5 mm long), membranous, truncate, erose-ciliate, and glabrous.
General Info
This drought-tolerant species can be found along roadsides, ditch banks, and swales, in salt deserts, sagebrush, pinyon-juniper communities, alkaline meadows, prairies, foothills, plains, and montane sites.
Similar Species
Western wheatgrass can look similar to thickspike wheatgrass (Elymus lanceolatus ssp. lanceolatus). To differentiate these two species from each other, look for glumes that are gradually tapering from below mid-length to an acuminate tip that is often slightly curved of western wheatgrass, and glumes that are broadest at or above mid-length with shortly tapering acute to acuminate tips of thickspike wheatgrass.
Picture of growth habit.
Close-up picture of spike inflorescence.
Close-up picture of spikelet.
Close-up picture of membranous ligule and auricle.
Close-up picture of prominent, upper leaf blade surface.
Illustration of western wheatgrass. USDA-NRCS PLANTS Database / Hitchcock, A.S. (rev. A. Chase). 1950. <i>Manual of the grasses of the United States</i>. USDA Miscellaneous Publication No. 200. Washington, DC.