Rough tree fern  (Cyathea australis)

The rough tree fern is listed on Appendix II of CITES (1).

This medium to large tree fern is particularly attractive with a robust black trunk and long, bright green fronds (3). It is known as the ‘rough’ tree fern due to the rough protuberances on the stalk of the fronds (2). The broad trunk, actually an above-ground rhizome, is also covered with rough, hair-like scales (4).

Subspecies: There are two subspecies – Cyathea australis australis and Cyathea australis norfolkensis.

Subspecies Cyathea australis australis is found in all eastern states of Australia, but subspecies Cyathea australis norfolkensis is found only on Norfolk Island, off the east coast of Australia (1).

This species is found within rainforests and open dry forests (5) to elevations of 1,300 metres (3).

The rough tree fern does not flower, but instead produces spores on the underside of the leaves, which drop off and germinate into small heart-shaped plants known as prothalli. These small plants create both male and female cells, which, once combined, result in a long-lived adult fern (4).

This species is not seriously threatened and is common in horticulture. The main threat to its survival in the wild is habitat loss, as forests are felled for farmland and urbanisation (1).

No targeted conservation action is in place for this species, but its place in horticulture ensures a reserve population.

For further information on fern species see the Australian National Botanic Gardens website:
http://www.anbg.gov.au/gnp/interns-2003/cyathea-spp.html