DESCRIPTIVE MANUAL 



53 



Fig. 29-A. Distribution of Poison Darnel. 



Extermination. — Sow clean oats or wheat. The weed succumbs 

 readily to cultivation. 



Quack Grass (Agropyron repens Beauv.). 



Description. — A perennial with a many-jointed, creeping rhi- 

 zome (root-stock) ; culm from 18 in-4 ft. high, bearing numerous 

 leaves from 5-12 in. long, and from Vs" 1 ^ i n - wide ; margins rough, 

 very smooth beneath, slightly hirsute above; spikes 6-12 in. long, 

 erect ; spikelets on opposite sides of a jointed and channeled rachis, 

 pubescent on the margin, erect, 4-8-flowered ; lower or sterile glumes 

 acute or short-awned, prominently 5-7-nerved, flowering glumes 

 smooth ; palet acute or somewhat rounded, smooth or slightly pube- 

 scent. 



The Western Wheat Grass (Agropyron smithii Rydb.) is closely 

 related to quack grass. The plant is glaucous; leaves are rigid, 

 bluish green in color, scabrous on the margin, edges rolling in; 

 spikelets 7-13 flowered, in a thicker spike ("head") than quack 

 grass; running root-stocks ("roots"). Common along railways 

 and in northwestern Iowa. This plant is not considered a weed. 

 It may be used to plant railway embankments. 



The Slender Wheat Grass (Agropyron tenerum Vasey) produces 

 a slender long head, greenish in color, running roots absent. 



Distribution. — This grass is common and widely distributed from 

 Manitoba, Minnesota, and western Iowa to Arkansas and Texas. 

 In Iowa it has been found and reported in the following localities : 

 Afton Junction, Ames, Armstrong, Iowa and Minnesota line nea' 

 Ceylon (Minnesota), Elmore, Hampton, Harcourt, Keokuk, Des 



