GRASSES OF IOWA. 345 



lets one to three-flowered, with narrow, lanceolate empty glumes, 4 to s 

 lines (8-10 mm.) long. June to August. 



Macoun's lyme grass is; found in Hamilton County, north to Kos- 

 suth County and westward. It occurs in low ground, especially in drains 

 and borders of lakes. 



DISTRIBUTION 7 . 



Ioiva. Rock Rapids 37 (Shimek) ; Elmore, Minn. (Iowa-Minne- 

 sota line) 1043 (Pammel) ; Rock Rapids 781 (Shimek) ; Jewell Junc- 

 tion (Carver); Ceylon 331 1, Elmore, Minn. (Iowa-Minnesota line) 

 1923, Spirit Lake 3226 (Pammel). 



North America. Iowa to Colorado (Larimer County, Greeley, 

 Ft. Collins, Ogden 35, Pammel), Montana and Oregon (Cusick). 



4. ELYMUS ARKANSANUS. 



Elymus Arkansanus Scribn. and Ball. Bull. U. S*. Dept. Agrl. Div. 

 Agros. 24: 45. /. 19. 1900. 



DESCRIPTION. 



Arkansas Wild Rye. A slender, erect perennial, with a short, 

 broad, bristly, nodding spike. Culm 3 to 4 feet (6-8 dm.) high, terete, 

 smooth, nodes smooth, sheaths mostly a little shorter than the internodes, 

 filiate on the margins or the lower sparsely hirsute-pubescent; ligule less 

 than 1 mm. long, membranaceous; leaf-blades 5 to 10 inches ( 1- 

 2 dm.) wide, narrowly lanceolate-acuminate, erect or ascending, auricu- 

 late at the base, scabrous below and on the margins, finely and densely 

 pubescent above. 



Spike long-exserted on the slender pedicel, nodding, 3 to 4^ inches 

 (6-9 cm.) long; internodes of the rachis angular, somewhat compressed, 

 hispid-ciliate on the margins, 1^ to 2 lines (3-4 mm.) long. Spikelets 

 two at each joint, two-flowered, the upper very small; empty glumes di- 

 vergent, linear-subulate, cylindrical and coriaceous at base, flattened, sca- 

 brous and two or three-nerved above, 4 to 5 lines (8-10 mm.) long, or, 

 including the stout, straight, scabrous awn, 1 to i-J- inches (2-3 cm.) 

 long; flowering glume narrowly lanceolate, acute, raised on a short stipe 

 and separating from it by a horizontal constriction, minutely scabrous, 

 three to five-nerved at apex, 3^ inches (7 mm.) long, terminating in a 

 straight, slender, scabrous awn, 1 to 2 inches (2-4 cm.) long. Palea 

 slighly shorter than its glume, rounded or slightly bidentate at apex, his- 

 pid on the keels above. June to August. See figure 244, on page 344. 



