Oca, Oxalis tuberosa
This is a tuberous plant known as oca, oka, or New Zealand Yam. It comes from the Andes but in the form pictured is not known in the wild. It was introduced to Europe in 1830 as a competitor to the potato and to New Zealand in about 1860, where it is now common.
Oca tubers form in the autumn. They are usually boiled before eating although they can be used raw. The leaves and young shoots can be eaten as a green vegetable.
The flavour is vaguely potato-like, with aromatic overtones. Tubers are variable in colour from purple to yellow but are commonly pink.
Oca can be boiled, baked or fried or used in soups and stews. The skins are high in oxalates. Andean preparation methods reduce the oxalate level by exposure to sunlight which also increases the sweetness.
The tubers are eaten raw in Mexico with salt, lemon, and hot pepper.
Pink Oca is a staple crop of the Andean highlands,second after the potato. It is easy to propagate and tolerates poor soil, high altitude and harsh climate.
Nigel Deacon, Diversity website
