The genus name Cyathea comes from the Greek word cyathos, which means cup, referring to the shape of the sori. Sori are the clusters that contain the spore bearing structures, found under the fronds. The species name australis means southern, referring to the distribution of the species, which were first described by Robert Brown in 1810 from a specimen collected on King Island in Bass Strait, off the coast of Tasmania.

“Rough” tree fern due to texture of trunk and fronds, which are hard and have sharp bumps on them, which makes them quite rough to touch. Plants often lose their fronds by the end of winter. The frond’s bases are often retained around the trunk, so an estimate of the tree-fern’s age can be made by counting the number of these vertically up the trunk. The Rough Tree-Fern shown here at top-right is around 120 years old.

Fossil ancestors of Rough tree-fern have been dated to the Carboniferous period, before amphibians first waked on earth. They are one of the earliest vascular plant forms on the planet (plants which circulate water internally), which proceeded flowering plants, conifers and cycads.

Ferns reproduce in the same manner more primitive algae and mosses. Spores are produced, released, then grow into a tiny heart-shaped structure known as the thallus. The thallus produces male sperm cells at the pointed end and female cells in the notch. When wetted, the sperm burst free from the thallus, are chemical attracted and swim to the female cells. Following fertilisation, an adult plant develops.

Rough Tree-Ferns are found in Wet forests and rainforests of all eastern states. The examples shown here are growing along in the Ford Creek, at map coordinates 58 157, 18 733. Click on any of the pictures to download a higher resolution image (T.Hastings October 2009).