About Alsophila australis R.Br.
Alsophila australis R.Br. typically grows a massive erect trunk up to 12 m tall, though specimens as tall as 20 m have been recorded from Queensland, Australia. Its fronds are bi- or tripinnate, and can reach 4 m in length, occasionally growing up to 6 m long. The fronds form a distinctive crown that is dark green on the upper surface and lighter green on the lower surface. The trunk bears adventitious roots, tubercles, and hair-like follicles. Plants growing in southern Australia often shed all their fronds by the end of winter, a trait also seen in Alsophila dregei from South Africa. A characteristic feature of this species is that stipe bases are often retained around the trunk long after they wither. Stipe bases are covered with scales and conical, blunt spines near their base. The scales range in color from shiny brown to bicolored (pale and brown), and are often distinctly twisted. Circular sori form on either side of the midvein of fertile pinnules. True indusia are absent, but small reduced scales may surround each sorus. Within its montane habitat, A. australis is ecologically important because it provides nesting substrate for Exoneura robusta, a native Australian reed bee. These bees almost exclusively build their nests in the pith of dead A. australis fronds. Since this bee species is an important pollinator for other plants in southeastern Australia, A. australis indirectly supports other plant species in its local ecosystem. In 1889, Joseph Maiden recorded a traditional use of this species by Aboriginal Australians: the starchy pulp from the top of the trunk is eaten raw and roasted. This whitish starchy tissue runs through the center of the trunk from base to apex, and when boiled it tastes like a bad turnip. Pigs will also feed on this pulp greedily. In cultivation, Alsophila australis is a robust tub plant that tolerates salty winds. It is a popular hardy cool-climate tree fern, and is adaptable to a wide range of climates and soils. In the wild, it grows in moist shady forest, in both coastal and montane areas, at altitudes up to 1,280 m (4,200 ft), and often grows alongside Dicksonia antarctica. This relatively hardy species is popular as a landscape plant and a container plant. As long as moisture levels stay high, it can tolerate frost, and will grow in full sun, or in shaded conditions in warmer regions. While it is well known in its native Australia, it is not commonly cultivated outside of Australia.
