canaigre

Rumex hymenosepalus, a species of dock native to southwestern North America with edible red stems and taproots containing tannin.

The true tannic acids are also widely distributed; […] in roots, as in the Texas plant, a Rumex commonly known as "Cañaigre;" […]

The Commissioner of Agriculture, in his report for 1878, speaking of this plant, says: "The examination of the canaigre, for tannin, shows the existence of a very abundant source of this important material, and gives reason for the belief that the latter at least may soon afford a cheap supply to the arts.["]

Tannin-containing matter obtained from the taproots of the plant.

The preparation of an extract of cañaigre for tanning is a new industry,[…]. The cañaigre extract will be used for light leather, and it is expected that a ready market can be found in England for the whole product, at very profitable prices, and the plant can be raised upon land which is practically useless for other agricultural purposes.

Futhermore, other vegetable tannins, such as ground Canigre, Quebracho, Babul bark, Mimosa tannin and pure tannic acid are found to have a similar virucidal effect and are as acerin not bactericidal.