The hardy and adaptable Cyathea australis or Spiky tree fern is found at Tree Fern Gully on the River-Forest section of the circuit.  It has roots and hair like follicles on its trunk giving it a rough texture and it is adaptable to a variety of climates and soils.  Ferns are also amongst the oldest plants in the world dating back to the Carboniferous period  360 million years ago and the Spiky Tree fern is wholly protected in Tasmania.