Bracken or Kilau Fern
Pteridium aquilinumThe Bracken Fern is found throughout the world outside the extreme polar latitudes, and too, at most elevations in Hawaii except the coldest. This Kilau or Pai`a, as it's known in Hawaiian, possesses underground runners that allow it to spread and overrun open areas and pastures. Plant parts are bitter but have been used as famine food and medicine in old Hawaii.