Biology Morphology Physiology Cyathea australis - Rough Tree Fern This impressive tree fern occurs in both rainforests and open dry forests. It's long, dark green fronds majestically sit atop the large woody trunk. It is found from the snowy south of Australia to sub-tropical Queensland. The Cyathea australis is one of the tallest growing tree ferns in Australia, and can tolerate higher exposure than the Dicksonia antarctica tree ferns. It is adaptable to a wide variety of soils and climates. The Cyathea australis is easy to care for as a garden feature or as a tub specimen. The name Rough Tree Fern is well suited, as the trunk and the back of the stripe are quite rough to touch. This makes it easy to distinguish it from other tree fern varieties. Unlike the Dicksonia antarctica which can be cut off above the ground, the Cyathea australis must have a rootball to be successfully transplanted. Cyathea is a large genus with estimates ranging from more than 600 species to more than 750 species of tree ferns, widely distributed throughout the world (Rickard 2000, Duncan and Isaac 1986).    The name Cyathea comes from the Greek word ‘kuathos’, a cup, referring to the cup-like indusium found in some species.  There are eleven species of Cyathea found in Australia while four of those are found in Victoria with Cyathea australis the most common and wide-spread; C.cunninghamii and C. x marcenscens are found together in southern regions while Cyathea leichhardtiana is restricted to the east of the state.   In the US, there is confusion between the Cyathea australis and Cyathea cooperi with the majority of tree ferns traded in the US in the past, Cyathea cooperi even though they may be labelled Cyathea australis.	Biology of Species Back to top Classification: Division – Pteridophyta Class – Pteropsida (also known as Filicopsida) Order – Filicales Family – Cyatheaceae Genera – Cyathea (Duncan and Isaac, 1986:9) The genus Cyathea is further classified in a number of different ways.  The most common is based on the distinctive scales at the base of the stipe that are either flabelloid or setiferous (Holtum 1964, Tyron 1970).  Subgenus Cyathea: Holtum classification system -  Cyathea australis (R Br.) Domin Tyron classification system –    Alsophila australis R. Br.
Morphology Back to top GENERAL APPEARANCE:    Cyathea australis is a tree-fern with a trunk to 10 m x 30 cm, covered by persistent stipe bases of fallen fronds.  The fronds which form a crown at the trunk apex, are oblong to lanceolate, to 3.5 x 1 m.  FRONDS:       Tripinnate.  Fertile and sterile pinnules similar, sessile oblong, to 18 x 5 mm, glabrous or with a few scales or hairs on midvein of lower surface; margins with shallow lobes.  Rhachises brown to green, glabrous but becoming rough towards base.  Stipe brown, hard, densely covered with sharply pointed tubercles and, at the base, with narrow, brown scales 1-3 cm long.  SORI:     Round, about 1 mm dia., non-marginal, indusium absent.  Sporangia rusty brown (Gullen and Walsh 1985) DISTRIBUTION:     Common throughout the Otways.  Cyathea australis can be found in cool temperate rainforest, wet sclerophyll forests, riparian forest, damp sclerophyll forests and pine plantations. Gullan, P. and Walsh, N., 1985, Ferns and Fern Allies of the Upper Yarra Valley & Dandenong Ranges, National Herbarium of Victoria, Department of Conservation, Forests and Lands.
	Physiology – Cyathea australis Back to top Cyathea australis is one of our tallest and most common tree ferns.  Experience has demonstrated that Cyathea australis is adaptable to a variety of soils and climates.  In temperate climates this tree fern will tolerate considerable exposure to sun.  Garrett (1996) notes Cyathea australis has a higher light requirement than Dicksonia antarctica and although the two species frequently grow together, Cyathea australis usually occurs on higher, drier slopes.  The species has been observed germinating from spores on disturbed but sheltered moist clayey soils that receive ample light.  Cyathea australis requires more care during the transplanting and re-establishment phase than Dicksonia antarctica.  According to Garrett (1996) a more detailed account of the ecology of Cyathea australis can be found in Neyland (1986).