Believe it or not, tumbleweeds—so strongly associated with wide-open expanses of the western United States—are actually weedy invaders from other continents. The most iconic and successful of these, the Russian thistle (Salsola tragus), came to America from central Asia in the 1870s, and is now found in 48 states.
Now, this species and another immigrant tumbler have given rise to a hybrid that has officially become a new species, named Salsola ryanii. Though only identified as a new species 14 years ago, it has already spread throughout the state, according to a study published in the American Journal of Botany.
Read more of the news article here