(-4but, was a native of southern Russia, where it was known as the Tartar
thistle.* It was probably unintentionally brought into the United States by
these immigrants in bags of flax seeds.*
Pra
It was agriculture that enabled the weed to spread so quickly. In the U.S.
(A)
Midwest, the tall prairie grasses would have made it impossible for
tumbleweeds to roll any great distance. Tumbleweeds thrive in ploughed
(カ)
fields, especially if it is sandy. Archaeologists have found tumbleweed seeds in
the oldest agricultural sites in the world. Without agriculture, tumbleweed can
live only in areas that are naturally open and bare.
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Frontier settlers gave the plant various names; saltwort, Russian cactus,
US Department of Agriculture