Eidothea
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Eidothea is a genus of two species of rainforest tree in Eastern Australia, which belongs to the plant family Proteaceae, which also includes more familiar members such as the waratahs, grevilleas, banksias, macadamias and proteas. The genus is named after Eidothea, one of the three daughters of Proteus in Greek Mythology.
That Eidothea has been found at localities as far apart as Cairns, Lismore and Ballarat, also underlines the fact that Australia’s rainforests are tiny remnants of ancient rainforests that covered vast areas of Australia until only a few million years ago. This makes them a particularly precious part of Australia's natural heritage.
Classification
The Proteaceae is a very old family of flowering plants that probably originated while the ancient supercontinent Gondwana was still in one piece. Gondwana consisted of what are now the continents of Australia, Africa, South America and Antarctica, as well as smaller bits and pieces such as New Zealand, New Caledonia and Madagascar. Gondwana began splitting up over 120 million years ago and the fragments carried a diverse array of plants and animals with them, including a variety of lineages of the Proteaceae. Eidothea is the only relic of one of those early lineages that has barely survived in the rainforests of eastern Australia. Other lineages went on to diversify spectacularly, resulting in hundreds of descendant species.
Eidothea lies within the subfamily Proteoideae, which contain such plants as Protea, Leucadendron, Leucospermum, and most other South African Proteaceae, Isopogon (Australian ‘drumsticks’), Adenanthos (Australian jugflowers), Petrophile (Australian ‘conesticks’), Conospermum (Australian smoke-bushes)
Fossil Record
We know that its appearance has not changed much for a long time because fossil fruits that look just like those of living Eidothea are known from rocks that are 15-20 million years old. These fossils were discovered in the 19th century in the Victorian goldfields by the State Government Botanist of the day, Baron Ferdinand von Mueller. The fruits are so unlike those of other Proteaceae that Mueller misidentified the fossils as belonging to something in the olive family. It was not until the fossils were matched with fruits from living Eidothea trees that their true identity was revealed.
Species
Two living species are known:
- E. hardeniana - is listed as an endangered species on Schedule 1 of the Threatened Species Conservation Act, 1995 and is known to occur in Nightcap National Park and in the adjacent Whian Whian State Forest.
- E. zoexylocarya - known only from the slopes of Mt Bartle Frere, near Cairns in North Queensland.
References
- Peter Weston (Pers. comm.)
- Weston, PH & Kooyman, RM (2002). "Eidothea hardeniana- Botany and Ecology of the ‘Nightcap Oak'". Australian Plants ([Australian Plants Society]) 21: 339–342.
- Douglas, AW & Hyland, BPM H (1995). "Telopea". in McCarthy, Patrick (ed.). Flora of Australia: Volume 16: Eleagnaceae, Proteaceae 1. CSIRO Publishing / Australian Biological Resources Study. pp. 127–128. ISBN 0-643-05693-9.
- Weston, PH & Kooyman, RM (2002). "Systematics of Eidothea (Proteaceae), with the description of a new species, E. hardeniana, from the Nightcap Range, north-eastern New South Wales.". Telopea 9: 821–832.
- Hoot, SB, and Douglas, AW (1998). "Phylogeny of the Proteaceae based on atpB and atpB-rbcL intergenic spacer region sequences.". Australian Systematic Botany 11: 301–320.
