Gymnostoma australianum
Species of tree endemic to Australia
From Wikipedia, the free encyclopedia
Gymnostoma australianum, sometimes known as oak,[4] is a species of flowering plant that is endemic to a restricted area of the Daintree tropical rainforests of north-eastern Queensland, Australia. It is a member of the 'she-oak' family Casuarinaceae, members of which are characterised by fine, drooping, evergreen foliage.[5] Superficially they look like some conifers such as Cupressus in the northern hemisphere and Callitris in the southern hemisphere.
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| Gymnostoma australianum | |
|---|---|
| |
| Foliage, fruits and flowers | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Embryophytes |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Fagales |
| Family: | Casuarinaceae |
| Genus: | Gymnostoma |
| Species: | G. australianum |
| Binomial name | |
| Gymnostoma australianum | |
Description
It grows into a small tree between 4 and 7 m (13 and 23 ft) tall with buttress roots and fissured bark. New shoots are covered in fine white or reddish brown hairs. The twigs are green and four-angled, and the leaves are reduced to tiny 'teeth' less than 1 mm (0.04 in) long.[4][5] The roots have nitrogen-fixing nodules.[6]
These trees may be either dioecious (with male and female flowers on separate plants), or monoecious (with both flowers on the same plant). Male flowers are borne on spikes about 2 mm (0.079 in) long; female flowers are without a perianth. The fruit is a small cylindrical cone about 10 mm (0.39 in) wide and long. They contain a number of samaras about 8 mm (0.31 in) long.[4][5]
Taxonomy
Gymnostoma is a small genus of 14 species (as of December 2025[update]), occurring in Malesia, the western Pacific, and Queensland. It was erected in 1980 by botanist Lawrence Alexander Sidney Johnson,[7] who also described this species in 1989.[6]
Distribution and habitat
This species is found in the area between the Daintree River and Cape Tribulation, in the vicinity of Thornton Peak. It has been described as a 'habitat specialist', being restricted to exposed sites with shallow, granite-derived, acidic soils such as stream banks, river islands and granite outcrops, and it does not colonise newly-disturbed areas of the surrounding rainforest. The altitudinal range is from sea level to about 1,350 m (4,430 ft), with the granite outcrops mostly occurring in the higher part of the range.[4][8][9]
Conservation
Gymnostoma australianum has been given the conservation status of vulnerable under the Queensland government's Nature Conservation Act.[1] As of December 2025[update], it has not been assessed by the IUCN.
