Taxonomic name: Cyathea cooperi (Hook. ex F. Muell.) Domin
Synonyms: Alsophila australis R.Br. var. cervicalis F.M.Bailey, Alsophila australis R.Br. var. excelsa F.M.Bailey, Alsophila australis R.Br. var. pallida F.M.Bailey, Alsophila cooperi Hook. ex F.Muell., Alsophila excelsa R.Br. ex Endl. var. cooperi (Hook. ex F.Muell.) Domin, Cyathea australis (R.Br.) Domin var. pallida (F.M.Bailey) Domin, Cyathea australis (R.Br.)Domin var. cervicalis (F.M.Bailey) Domin, Cyathea brownii Domin var. cooperi (Hook. ex F.Muell.)Domin, Sphaeropteris cooperi (Hook. ex F. Muell.) R. M. Tryon
Common names: Australian tree fern (English), Cooper's cyathea, fanjan Australien (French), fougère arborescente d'Australia (French), lacy tree fern, scaly tree fern, straw tree fern (English)
Organism type: fern
Native to Queensland, Australia, Cyathea cooperi has invaded several islands in the Pacific. It is a fast growing fern that displaces native vegetation easily by forming dense stands. C. cooperi has become a problem in Hawaii by displacing its native ferns. It spreads its spores very easily by wind and proceeds to grow within a few weeks. It can grow up to 12m high and its fronds can grow up to 5m long.
Description
Cyathea cooperi can grow up to 12m in height (Wilson, 2007). The stipe base of Cyathea cooperi has two different types of scales. The first being dark, small scales and the other being large, pale, papery scales. The latter is the reason for the shaggy blond mat of scales that forms.
After the leaves die, the stipes will fall off at the trunk leaving oval scars (Medeiroset al, 1992). The sorus lacks an indisium and has a ring of small scales around the sporangia (Heenanet al, 1998). The fronds of C. cooperi can grow up to 5m long (Wilson, 2007). HEAR (2006) states, "Blades 2-pinnate-pinnatifid to 3-pinnate at base, green or light green above, paler below; rachises with dark brown, obtuse tubercles.
Pinnae up to 65 x 26cm. Pinnules stalked, tips acuminate. Ultimate segments deeply pinnatifid to 1-pinnate, segment lobes falcate, margins irregularly toothed or rarely deeply lobed. Veins 1-forked." In older Cyathea cooperi a tight rosette will form at the top of the trunk.