44 MINNESOTA WEEDS 



in grain fields. Good plowing, thorough cultivation, with some hand 

 hoeing and pulling, will eradicate the weed from cultivated crops. 

 It does not give serious trouble in fields where crops are grown in a 

 good rotation. It is most troublesome in gardens, but shallow cul- 

 tivation and hoeing or pulling by hand will eradicate it. 



Russian Thistle (SalsoLa tragus L.) 



Other common name. — Tumble weed. 



Description. — This is an annual weed which is supposed to have 

 come from Russia in some imported flaxseed. The plant is from 

 one to three feet high and covers an area ranging from a few inches 

 to six feet in diameter. It has a bushy appearance because of its 

 profuse branching. The color is light green and the stem, branches, 

 and upper leaves are striped longitudinally with reddish purple lines. 

 The root is a small white tap root. The leaves are small and each 

 tapers to a sharp spine. These spines account for the fact that the 

 plant is called a "thistle, " even though it does not belong to the true 

 thistle family as the bull and Canada thistles do. The flowers are 

 nearly hidden by the spines. They are generally of a bright rose 

 color, very thin, and papery. It is estimated that a good sized plant 

 will produce from 100,000 to 200,000 seeds. 



The seed is sometimes covered with a thin gray hull. When 

 this coat is removed the seed has the appearance of a snail shell. 

 This is because the embryo is spirally coiled. 



The seed is found in flaxseed, grass seed, and clover seed, but 

 most especially in western alfalfa seed. The plant flowers from 

 July to August, and usually matures its seed late in August and 

 during September and October. In autumn the stem becomes weak 

 and brittle just above ground and the entire plant breaks away and 

 tumbles over the ground, scattering its seeds as it goes. This gives 

 it the name tumble weed. The plant is very common in this State 3 

 i pecially in light, sandy soil. It thrives in dry seasons, but is easily 

 kept in check by growing crops in wet seasons. 



Eradication. — Prevent Russian thistles from maturing by cul- 

 tivation or harrowing. The plants are easily destroyed while small, 

 but if they mature, they should be gathered and burned before they 

 break loose and blow away scattering seeds as they go. Good plowing 

 and careful seeding or planting so as to occupy the land fully will 

 prevent the growth of the Russian thistle in most seasons. Plants 

 -row in- on waste places should be destroyed or burned at maturity 

 to prevent seeds blowing over the; fields. 



