Sisymbrium altissimum (Jim Hill Mustard or Tumble Mustard)

This mustard dries into a rolling tumble weed, spreading seeds everywhere it blows. It is an annual, and can be easily pulled up. In the two lower photos, this mustard is shown with its cousins. They all colonize disturbed ground, along roads and in neglected or over-grazed meadows.

In the photo above, Sysimbrium altissimum keeps company with Descurainia sophia.

Here we see Sysimbrium altissimum next to Thlaspi arvense.