Alsophila ferdinandii, synonym Cyathea macarthurii, is a fern in the family Cyatheaceae. Description The plant is a treefern with a trunk up to 4 m in height, either shaggy with dark frond bases, or clear with round scars. The fronds, growing to 50 cm, have prickly stipes covered with a light brown, woolly indumentum. Distribution and habitat The fern is endemic to Australia’s subtropical Lord Howe Island in the Tasman Sea. The commonest tree fern on the island, it is widespread from the lowlands to the mountains. References ferdinandii Endemic flora of Lord Howe Island Plants described in 1874 Ferns of Australia