Rumex salicifolius

Rumex salicifolius is a species of flowering perennial plant in the knotweed family known by the common names willow dock and willow-leaved dock. It is native to much of western North America, and more specifically, in southern and central parts of California, and some parts of Arizona and Nevada. It can also be found in parts of Europe as an introduced species and a roadside weed. It is an extremely variable plant which is generally divided into many varieties, some of which may actually be specimens of other species....read more on Wikipedia.