Scientific Name
Achnatherum thurberianum (Piper) Barkworth (Synonyms: Stipa thurberiana)
Common Name(s)
Thurber's needlegrass
Tribe / Family Name
Stipeae
Flowering Period
June to August
Symbol
ACTH7
Description
Thurber’s needlegrass is a native cool-season perennial bunchgrass that reproduces from seeds and tillers. Culms range from 30–75 cm in height. Its inflorescence is a narrow panicle 7–15 cm long with relatively few spikelets. Spikelets are 1-flowered and awned (the lemma awns 32–56 mm long, twice geniculate and pilose along the first two segments [hairs 0.8–2 mm long], and glabrous or often scabrous along the terminal segment). Ligules are 1.5–8 mm long, membranous, hyaline, acute, and lacerate.
General Info
Thurber’s needlegrass can be found in sagebrush steppe, juniper woodlands, canyons, foothills, plains, and montane sites.
Similar Species
Thurber’s needlegrass looks similar to other needlegrass (Achnatherum) species, especially western needlegrass (Achnatherum occidentale). Both species have awns that are hairy along the first two segments, but can be differentiated from each other by inspecting the length of the ligules. Thurber’s needlegrass has ligules that are up to 8 mm long, and western needlegrass has ligules that are up to 2 mm long. Also, Thurber’s needlegrass often has a purple-tinged, membranous glume, and western needlegrass has a straw-colored, papery glume.
Picture of growth habit.
Close-up picture of narrow panicle inflorescences.
Close-up picture of spikelet.
Close-up picture of palea (left), evenly pubescent lemma (center), and hairy awn (top).
Close-up picture of subequal glumes.
Close-up picture of membranous ligule.
Close-up picture of white, hairy nodes.
Illustration of Thurber's needlegrass. 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.