Pascopyrum smithii

(Rydb.) Barkworth & D.R. Dewey
Common names: Western wheatgrass
Synonyms: Elytrigia smithii unknown Elytrigia dasystachya unknown Elymus smithii unknown Agropyron spicatum var. molle unknown Agropyron smithii var. palmeri unknown Agropyron smithii var. molle unknown Molle unknown Agropyron smithii unknown Agropyron elmeri unknown
Treatment appears in FNA Volume 24. Treatment on page 351.
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Illustrator: Cindy Roché
Culms 20-100 cm, glabrous. Auricles 0.2-1 mm, often purple; ligules about 0.1 mm; blades 2-26 cm long, 1-4.5 mm wide, decreasing in length upwards, spreading, rigid, adaxial surfaces with prominent veins. Spikes 5-17 cm; middle internodes 4.5-11 mm. Spikelets 12-26(30) mm, with 2-12 florets; lowest rachilla internodes in each spikelet 0.8-2 mm long, 0.5-0.9 mm wide at the top. Glumes 5-15 mm, lower glumes usually exceeded by the upper glumes; lower glumes 0.15-0.8 mm wide at 3/4 length; lemmas 6-14 mm, unawned or awned, awns 0.5-5 mm. 2n = 56.


Wash., Wis., Wyo., N.H., N.Mex., Tex., Mass., Tenn., N.Y., Calif., Nev., Colo., Alaska, Kans., N.Dak., Nebr., Okla., Ark., Ill., Ga., Ind., Iowa, Ariz., Idaho, Alta., B.C., Man., Ont., Que., Sask., Ohio, Utah, Mo., Minn., Mich., Mont., Ky., Oreg., S.Dak.


Pascopyrum smithii is native to sagebrush deserts and mesic alkaline meadows, growing in both clay and sandy soils. Pascopyrum smithii is probably derived from a Leymus triticoides-Elymus lanceolatus cross (Dewey 1975); it is frequently confused with both. Leymus triticoides differs in usually having 2 spikelets per node and glumes that are narrower at the base. In E. lanceolatus, the leaves tend to be more evenly distributed and the glumes have straight midveins, become narrow beyond midlength, and tend to be wider at 3/4 length (0.35-1.6 mm). In addition, the first rachilla internodes of E. lanceolatus are often longer and narrower (the length/width ratio averaging 2.6, versus 1.8 in P. smithii). No infraspecific taxa of P. smithii are recognized here.



Lower Taxa

No lower taxa listed.

Facts about "Pascopyrum smithii"
AuthorMary E. Barkworth +
Authority(Rydb.) Barkworth & D.R. Dewey +
Common nameWestern wheatgrass +
DistributionWash. +, Wis. +, Wyo. +, N.H. +, N.Mex. +, Tex. +, Mass. +, Tenn. +, N.Y. +, Calif. +, Nev. +, Colo. +, Alaska +, Kans. +, N.Dak. +, Nebr. +, Okla. +, Ark. +, Ill. +, Ga. +, Ind. +, Iowa +, Ariz. +, Idaho +, Alta. +, B.C. +, Man. +, Ont. +, Que. +, Sask. +, Ohio +, Utah +, Mo. +, Minn. +, Mich. +, Mont. +, Ky. +, Oreg. + and S.Dak. +
IllustratorCindy Roché +
ReferenceNone +
Source xml grained fna xml/V24/V24 1128.xml +
SynonymsElytrigia smithii +, Elytrigia dasystachya +, Elymus smithii +, Agropyron spicatum var. molle +, Agropyron smithii var. palmeri +, Agropyron smithii var. molle +, Molle +, Agropyron smithii + and Agropyron elmeri +
Taxon familyPoaceae +
Taxon namePascopyrum smithii +
Taxon parentPascopyrum +
Taxon rankspecies +
VolumeVolume 24 +