Colocasia is a genus in the Araceae family. Colocasia esculenta, commonly called Taro or Elephant's Ear, is grown in Hawaii and other Pacific islands for its starchy roots, which are harvested as a staple food. This is not a recommendation to consume this plant unless the plant is thoroughly processed as it contains Calcium oxalate which can cause serious reactions (itching, stinging, burning internally or externally lasting for a short time or for days.) Edible qualities of Colocasia roots raised for eating and sold in grocery stores are the only ones you should eat.
Colocasia esculenta var. antiquorum 'Illustris' has black leaves with green veins and grows well in moist soils in part-shade. It also grows well in full sun if provided with sufficient moisture, like in a bog or at the edge of a pond. Photos taken by Jay Yourch.