When Selk'nam inhabited Tierra del Fuego fell into various tribes, two of them were in great conflict, the leaders of both communities are hated to death. One of them had a young son, who liked to walk the fields. On one occasion he found a beautiful girl intense black eyes and fell in love with her.
Unfortunately, it was the daughter of his father's enemy, the only way was to be hidden, but the witch of the tribe of girls discovered. Vio however, that he could not separate them and ordered the girl, transforming it into a plant that kept all the beauty of its black eyes, but with thorns, so that the young lover could not touch. But the love was so strong that the young man never seceded from the plant and died at his side.
So everyone that will eat the fruit of this shrub is intended to return to Patagonia, because one can not be separated from power of love is on the calafate, attracts us to him and we are not allowed to leave us for a long time.