Oxalis tuberosa is a perennial herbaceous plant that overwinters as underground stem tubers. These tubers are known as uqa in Quechua, oca in Spanish, yam in New Zealand and a number of other alternative names. The plant was brought into cultivation in the central and southern Andes for its tubers, which are used as a root vegetable. The plant is not known in the wild, but populations of wild Oxalis species that bear smaller tubers are known from four areas of the central Andean region. Oca was introduced ...