56 WEEDS OF THE FARM AND GARDEN 



narrower leaves. It is common in Missouri, Illinois, 

 Iowa, Nebraska and Kansas, extending east as far as the 

 Atlantic coast. 



Field dodder is common not only on native herbage 

 clear across the continent, but also occurs on clover. The 

 clover dodder appears in California, Utah, Colorado, 

 Montana, Missouri, and Iowa on alfalfa and clover. 



Pepper grass (Lepidium virginicum) furnishes an im- 

 purity for alsike and blue grass. 



Persicaria, or lady's thumb (Polygonum Persicaria), 

 and the two ragweeds are common in many meadows. 

 Among the common weedy grasses are foxtail (Setaria 

 glauca), crab grass (Digitaria sanguinalis) and barnyard 

 grass (Echinochloa crus-galli). 



On the plains and ranches in Colorado and Utah occur 

 many bad weeds. The Russian thistle (Salsola Kali, var. 

 tenuifolia) is easily one of the most common weedsi in 

 eastern Colorado, coming up not only in the streets, but 

 also along roadsides and in fields. In the early days of 

 the Russian thistle it was thought that it would prove a 

 very troublesome weed in the more humid conditions of 

 our country. Thus far it has not, but in the West it has 

 found ideal conditions for development. Another weed 

 which has become abundant is the tumbling mustard 

 (Sisymbrium altissimum), which is found in many places. 

 It has light yellow, mustard-like flowers, and later stiff 

 pods without leaves. Sweet clover grows everywhere 

 along roadsides and streets in eastern Colorado and 

 stands drought well. On some of the foothills and streets 

 of the eastern slope of the Rockies a species of brome 

 grass (Bromus tectorum) is becoming abundant. It is an 

 annual which grows/ with very little moisture and is 

 crowding out many more valuable grasses, and alfalfa. It 

 is particularly common near Colorado Springs, Salt Lake 

 Basin and in California. It has little value for forage pur- 

 poses; the hay is light, and moreover the plant is injuri- 



