They are called tumbleweeds.
Tumbleweed, Russian thistle and wind witch are common names for this symbol of the American west. Russian thistle alludes to its Eurasian origin. Scientific names for tumbleweed include Salsola kali, S. pestifer, S. australis, S. iberica, and S. tragus. Salsola is derived from the Latin sallere, "to salt," in reference to the plant’s salt tolerance. There does not yet appear to be a consensus on the preferred scientific name, although S. tragus is the leading candidate for the inland variety of tumbleweed and S. kali, for the more coastal variety.
As it rolls down a desert road, Russian thistle plants do what they do best, disperse seeds, which typically number 250,000 per plant. Seeds are unusual in that they lack any protective coat or stored food reserves. Instead, each seed is a coiled, embryonic plant wrapped in a thin membrane. To survive winter without a warm coat, the plant does not germinate until warm weather arrives.
When moisture falls, the plant is ready to uncoil and germinate. All that is required are temperatures between 28 and 110 degrees Fahrenheit. It then quickly sends up two needle-like leaves and begins to shoot skyward. By autumn the plant has reached maximum size, flowered and begun to dry out.
Of interest, check out these 9 desert plants you can turn into cookies, candy and margaritas shared by Indiancountrytodaymedianetwork.com.