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GRASSES OF THE COLUMBIA
BASIN OF BRITISH COLUMBIA
This genus is the centre of some controversy due to the re-interpretation of Agropyron. Several species that were originally included in Agropyron by Hitchcock (1951) have been placed in this genus. The species in this genus originate in the Mediterranean region, have been cultivated for forage and erosion control, and are well suited to alkaline soils. In British Columbia there are two Thinopyrum species -- Thinopyrum ponticum and Thinopyrum intermedium -- but only T. ponticum has been collected. T. intermedium (syn. Agropyron intermedium) is likely to occur in the Columbia Basin in the future as an introduced species.
Leaves and Stem: The open leaf sheath is hairy along the margins but smooth across the back of the sheath. The ligules are inconspicuous with some small hairs. The stiff leaf blade is 2-6.5 mm wide, rolled inward and thick-veined, but the magins are not thickened. The auricles are 0.2-1.5 mm long and erect rather than clasping the stem. Flowerhead and Flowers: The slender spike is stiff and 10-42 cm long. The glume tip is blunt and the glumes are weakly keeled. The glumes are shorter than the first flower. The spikelets are slightly longer than the internodes to more than twice as long. The lemmas are prominently nerved and have blunt tips with either no awns or are minutely awn-tipped. The stem axis in the flowerhead does not break apart at maturity. Similiar Species: The spikelets of Tall Wheatgrass and of Intermediate Wheatgrass both have a blunt, clublike appearance due to the lack of awns, but they differ most notably in their leaf blade edges. Intermediate Wheatgrass has thickened leaf blade edges with some hairiness on the upper surface and it has a rhizome. Tall Wheatgrass has no thickened margins and the blades are rough or densely hairy. It is tufted rather than having a rhizome. This species is called Elymus elongatus in Douglas et al. (1994), and is similiar to Elymus hispidus in Douglas et al. (1994), but the presence of a rhizome in Elytrigia intermedia separates the two.
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BC Museum |
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Habitat: Tall Wheatgrass is common in the southern Columbia
Basin and was introduced from southeastern Europe and western Asia
for forage and soil stabilization. It grows along dry roadsides
and on dry slopes in the steppe to alpine zones. In the Columbia
Basin it occurs near Cranbrook, Marysville and Grand Forks.