(Rumex hymenosepalus)
Rumex hymenosepalus, commonly known as canaigre, canaigre dock, ganagra, wild rhubarb, Arizona dock, and tanner's dock,is a perennial flowering plant which is native to the North American deserts in the southwestern United States and northern Mexico. It is a common food plant of the ruddy copper larvae. It has been cultivated in the southwestern United States for the roots, a good source of tannin, which is used in leather tanning. It also yields a warm, medium brown dye. The leaves and leaf stalks are considered edible when young, the older leaf stalks cooked and eaten like rhubarb, which is in the same plant family. Rumex hymenosepalus was first described by American botanist John Torrey in the Report on the United States and Mexican Boundary in 1859.