Cyathea australis, commonly known as the Rough Tree Fern or Australian Tree Fern, is a species of tree fern that is native to southeastern Australia, including Tasmania. It is a tall fern that can grow up to 30 feet (9 meters) tall with a trunk up to 1 foot (30 cm) in diameter. The Rough Tree Fern has a unique appearance, with a thick, fibrous trunk covered in rough, brown scales and a crown of large, dark green fronds that can reach up to 12 feet (3.5 meters) in length. The fronds are finely divided into many small leaflets, giving them a delicate, lacy appearance.