Scientific Name
Trisetum spicatum (L.) K. Richt. (Synonyms: Aira spicata; Trisetum montanum; Trisetum subspicatum; Trisetum triflorum; Trisetum villosissimum)
Common Name(s)
Spike trisetum, downy oatgrass, narrow false-oats
Tribe / Family Name
Poeae
Flowering Period
June to August
Symbol
TRSP2
Description
Spike trisetum is a native cool-season perennial bunchgrass that reproduces from seeds and tillers. Culms range from 10–120 cm in height. Its inflorescence is a dense, spike-like to open panicle usually 2–12 cm long, often interrupted at the base, green, purplish, or tawny, usually silvery, and bristly. Spikelets are 5–7.5 mm long, 2(3)-flowered, and awned (awns are 3–8 mm long, geniculate, twisted at the base, and attached just below the tips of the lemmas). Ligules are up to 4 mm long, membranous, rounded to truncate, erose or occasionally finely ciliate, and glabrous.
General Info
Spike trisetum can be found along roadsides, in open woodlands, moist meadows and forests, on rocky ledges, subalpine, and alpine slopes.
Similar Species
Spike trisetum may be confused with other grasses such as pinegrass (Calamagrostis rubescens), prairie junegrass (Koeleria macrantha), and bluegrass (Poa) species, especially after their seed heads open up. Another distinguishing characteristic are the number of awns. Spike trisetum has 2 awns (sometimes 3) and pinegrass has 1 awn. Prairie junegrass is rarely awned and bluegrass species are unawned.
Picture of growth habit.
Inflorescence is a dense, spike-like panicle.
Close-up picture of spikelet.
Close-up picture of ligule.
Illustration of spike trisetum. 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.