MINNESOTA WEEDS, SERIES III ly 



inch broad and generally clustered at the top of the plant. The seeds 

 are more or less spherical in shape and are dark reddish brown. The 

 surface of the seed is marked by a network of veins which give it a 

 honeycombed appearance. This, however, is not easily seen except 

 with a magnifying glass. Indian mustard seed is found most com- 

 monly in the commercial seed of timothy, millet, red clover, alfalfa, 

 flax, and cereals. 



Eradication. — The same methods of eradication as are advised for 

 ball mnstard will be effective for Indian mustard. 



Tumbling Mustard (Sisymbrium altissimiim L.) 



Other common names. — Tall sisymbrium, tumble mustard, white 

 mustard. 



Description. — Tumbling mustard is an annual or winter annual 

 plant which blossoms from June to July and seeds from July until 

 frost. It is most commonly found in grain fields, waste places, and 

 along roadsides, and in some of the western states it is considered a 

 very serious weed pest. It is a fairly bad pest in this state, but not 

 nearly so troublesome as some of the perennial weeds. The plant 

 grows from two to four feet high and is much branched and bushy. 

 As soon as the seeds are ripe, the plant breaks away readily from its 

 roots just above the surface of the soil and is tumbled about by the 

 wind. In rolling along the seeds may be scattered, and in this way 

 it becomes quite widely distributed, as it propagates only by seed. 

 The flowers of the tumbling mustard are pale yellow or cream color 

 and are about one quarter of an inch in diameter. The seed pods are 

 very long and slender, often containing from one hundred to one hun- 

 dred twenty small brown or greenish yellow seeds. When this plant 

 is very abundant in grain fields it interferes with cutting and elevating 

 in self-binders. The seeds of tumbling mustard are found most com- 

 monly in the commercial seed of timothy, white clover, and redtop. 



Eradication. — Clean seed grain carefully and prevent any mustard 

 plants from going to seed. Pull stray plants by hand, carry them 

 from the field, and burn them. These weeds usually appear at the 

 edges of fields or where recently burned over but may appear in grain 

 crops. If so, cultivate early in the season with a weeder or light har- 

 row and pull by hand. 



