Also Known As: Rumex hymenosepalus, Canaigre, Ganagra, Wild rhubarb, Arizona dock, Tanner's dock
Rumex hymenosepalus, commonly known as canaigre, ganagra, wild rhubarb, Arizona dock, or tanner's dock, is a perennial flowering plant which is native to the United States and Mexico. It has been cultivated in the southwestern United States as the roots are a good source of tannin, for use in leather tanning. It is also a source of a mustard-colored dye.
The plant is adapted to very dry environments. The leaf is waxy and ridged so that water from light, misty rain collects along a central vein and filters down to the taproot. Scientists call this process the plant's method of "self-irrigating".