What are tumbleweeds?

Tumbleweeds are made up twigs and straw and dust what mainly rumble around western towns.

AnswerIn the western US, most tumbleweeds are individual plants of the Salsola genus, part of the Chenopodiaceae family. When mature, the mostly dried up plant gets broken free from its roots by the wind or some other mechanism, and blows free to spread its seed as it rolls.