Gunnera chilensis.

Botanical name: 

Gunnera chilensis Lam. Halorageae.

Chile. The acidulous leaf-stalks serve as a vegetable. The plant somewhat resembles rhubarb on a gigantic scale. The inhabitants, says Darwin, eat the stalks, which are subacid. The leaves are sometimes nearly eight feet in diameter, and the stalk is rather more than a yard high. It is called panke. In France, it is grown as an ornament.


Sturtevant's Edible Plants of the World, 1919, was edited by U. P. Hedrick.

Comments

"You made a typo. This plant is called in the South of Chile 'Nalca'. Not what you wrote ('Panke').
In spring and early summer you see a lot of people selling the stalks. It makes a very refreshing drink. It taste somewhat like Rhubarber.

Greetings from the South of Chile,
Paul van Oss, Los Lagos."

I think that "panke" refers to the old latin name (Panke tinctoria Molina), not any possible common names. But thank you for that local name!