SLENDER WHEATGRASS--Elymus trachycaulus (Agropyron trachycaulum, A. subsecundum, A. caninum)
Description:  Slender wheatgrass, a cool-season, perennial bunchgrass 2 to 4 feet tall, takes its name from the spicate inflorescence which tends to be narrower than those of other common wheatgrasses.  Glumes are almost as long as the entire spikelet and are prominently nerved.  Both glumes and lemmas are generally without hair.  Leaf blades are flat and usually glabrous.  Leaves and stems are often purplish tinted.  Two forms are generally recognized, beardless, subsp. trachycaulus, with short awns < 1/4 inch, and bearded, subsp. subsecundus, with long awns 1/4 to 1 inch.
Habitat, distribution:  Slender wheatgrass is native to a wide variety of habitats from Alaska to Newfoundland, south to Mexico, and in all but the southeastern states.  Across South Dakota, slender wheatgrass is common in a variety of grasslands, including those in the Black Hills.  It is usually scattered but often abundant in the grasslands of the glaciated northeastern plains.
Comments:  Good seeding development contributed to early use of slender wheatgrass for reseeding.  Since it is short-lived, it is seldom planted in pure stands.  In localized areas, slender wheatgrass is sufficiently abundant to be very important.  Although considered to be a decreaser, reports are conflicting on palatability.  In some areas it is relished by livestock and wildlife, particularly when compared to other wheatgrasses.  It is alkali tolerant and low in drought resistance.
Picture and information can be found on pages 36 and 37 of Grassland Plants of South Dakota and the Northern Great Plains, by James R. Johnson and Gary E. Larson.  Published in 1999 by South Dakota State University, Brookings, SD.