There are four main species of tree ferns found in Tarra Bulga National Park, (along with many other fern species) The two most common you will see are Cyathea australis (Rough tree-fern) and Dicksonia antarctica (Soft tree-fern). The Soft Tree-fern is more common in the moister areas including the rainforest gullies while the Rough tree-fern is more dominant on the slopes. Once you get you eye in it is fairly simple to tell the difference between these two, the most obvious being by comparing the trunks. The Rough tree-fern has much of its trunk covered by the remains of broken off stems (Stipes) Which are rough to the touch, while the Smooth tree-fern is soft to the touch and is covered by masses of soft hairs which are actually roots. On this soft trunk other species of plants will often grow including tree and shrub seedlings, epiphytes and other ferns.
Other key ways to tell the difference between these two common ferns is by feeling the base of the frond stems (known as stipes). The Rough tree-fern is easy to tell once again by running your fingers along the stem and feeling the rough texture.
Another way to tell the difference between these two ferns is to examine the underside of the fronds and search for small yellow discs called Sori (they are groups of sporangia which is where ferns produce and store their spores). The Rough tree-fern has sori in rows closer to the mid-vein of the leaf whilst the Smooth tree ferns are located on the leaf margins and are protected by the edges of the fern leaf curling around them.
Another key difference between the two are croziers (which are the coiled up newly developing fern fronds). The Cyathea (or Rough tree-fern) has shiny scales and the Dicksonia (Soft tree-fern) is covered with coarse hairs.