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GRASSES OF THE COLUMBIA BASIN OF BRITISH COLUMBIA Heather Stewart, Richard Hebda Major Groups of Grasses Table of Contents Glossary Pascopyrum Western Wheatgrass Pascopyrum is one of the new genera created from splitting Agropyron to match genetic evidence (Barkworth and Dewey, 1985). The name comes from the Latin pascuum, meaning pasturi, and the Greek pyros, meaning wheat. The genus contains one species, Pascopyrum smithii, which is endemic to North America. Pascopyrum is very similar to Elymus, and is the result of a hybrid cross between Leymus triticoides and Elymus lanceolatus (Davey 1975). In Hickman (1993), Pascopyrum is separated from Elymus because of its sharp-pointed glumes that are widest at the middle and curved to one side. Pascopyrum also has a blue-green colour on the leaves as well as the flowerhead. In contrast, Elymus has straight glumes that are widest below the middle, and the tip of the glume ranges from pointed to blunt.   Pascopyrum smithii (Rydb.) A. Love Agropyron smithii Rydb. Western Wheatgrass Pasture Wheat Plant: Pascopyrum smithii is a native species that grows to 20-100 cm tall. It is a bluish perennial that forms large clumps, and it has a spikelike flowerhead consisting of usually one, but occasionally two, spikelets per node. Leaves and Stem: The smooth, open sheath has auricles that are .2-1 mm long, and clasp the stem. There is a short, membranelike ligule. The leaf blades are 2-6 mm wide, strongly nerved and inrolled, stiff and a pale blue-green colour. Flowerhead and Flowers: The spikelike flowerhead bears one or two spikelets per node. The almost overlapping spikelets have 6-10 flowers. The slightly curved glumes are widest at the middle and are tapered from the base to the middle and tapered again to a sharp tip. The longer glume equals the first lemma. The lemmas are lance-shaped, rounded on the back, either smooth or hairy, with an awn tip up to 5-15 mm long. The palea is as long as the lemma. Habitat: Western Wheatgrass is a common grass of dry, alkaline soils and flats, such as those around Cranbrook, Canal Flats and Fort Steele. Similar Species: This species was part of the Agropyron complex. It has been moved out of that genus and put into Pascopyrum, which has only one species. Western Wheatgrass is very similiar to Elymus lanceolatus ssp. lanceolatus, especially in a vegetative state. The differences between the genera Pascopyrum and Elymus are: the shape of the glumes; the acute tip of the glume vs the obtuse tip; the strongly hairy inflorescence vs hairy.

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