Rough tree fern

Description

The massive erect trunk is usually up to 12 m tall, although specimens reaching 20 m have been reported from Queensland, Australia. Fronds are bi- or tripinnate and may reach 4 m in length, occasionally even 6 m. These form a distinctive crown that is dark green above and lighter green below. The Tree Fern has quite adventitious roots, tubercles and hair-like follicles on its �trunk�.Plants growing in southern Australia often lose their fronds by the end of winter, as is the case with Cyathea dregei in South Africa. Characteristically of this species, stipe bases are often retained around the trunk long after withering. They are covered with scales and conical, blunt spines towards the base. The scales range in colour from shiny brown to bicoloured (pale and brown) and are often distinctly twisted. The sori are circular and occur on either side of the fertile pinnule midvein. True indusia are absent, although reduced scales may encircle the sori.In its montane range, C. australis is ecologically important as it provides the nesting substrate for Exoneura robusta, a native species of reed bee. These bees almost exclusively build their nests in the pith of dead C. australis fronds. This species of bee is an important pollinator of other plants in southeastern Australia, so thus it can be seen how C. australis is indirectly supportive of other plants in its ecosystem.