6. Elymus longifolius (J.G. Sm.) Gould (squirreltail)

Pl. 187 a, b; Map 751

Sitanion longifolium J.G. Sm.

S. hystrix (Nutt.) J.G. Sm. var. brevifolium (J.G. Sm.) C. Hitchc.

E. elymoides (Raf.) Swezey ssp. brevifolius (J.G. Sm.) Barkworth

Plants without rhizomes, forming tufts. Flowering stems 20–55 cm long, glabrous. Leaf blades 2–16 cm long, 1.5–5.0 mm wide, flat or with the margins inrolled, glabrous, roughened or less commonly hairy on the undersurface, with a pair of usually prominent auricles at the base. Inflorescences 7–15 cm long, erect or slightly arched, appearing somewhat flattened, with clusters of mostly 2 spikelets per node, disarticulating at the nodes at maturity, the joints shed as a unit with the attached spikelets. Spikelets with 2 or 3(–6) florets, loosely ascending. Glumes similar in size and appearance, 40–110 mm long (including the long awn), the body 8–10 mm long, 1–3 mm wide, linear to narrowly lanceolate, 1‑nerved, somewhat thickened and hard toward the base, glabrous, tapered indistinctly into a long, roughened awn that is bent or curved outward at maturity. Lemmas with the body 7–12 mm long, elliptic‑lanceolate, faintly 3‑ or 5‑nerved, roughened or hairy, the tip with the awn 25–100 mm long, roughened, bent or curved outward at maturity. Paleas mostly 6–12 mm long. Anthers 1–2 mm long. 2n=28. May–June.

Introduced, known from a single historical specimen from Jackson County (western U.S. and adjacent Mexico east to South Dakota and Texas). Habitat unknown, but probably a highly disturbed area, such as a roadside.

Some authors treat this taxon as a variety or subspecies of the widespread and closely related E. elymoides (Sitanion hystrix). It belongs to a small group of four species native to western North America that are sometimes segregated as the genus Sitanion, based on their shattering inflorescence axis. Further west, the species is considered undesirable in pastures and on rangeland, because the long awns can cause injury to the noses, eyes, mouths, and intestines of cattle and other species that attempt to graze on them.