Fruits/Seeds
Fruit case distally pointed, containing 1 - 2 black seeds.
Field Guide
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Grass-tree
Did You Know?
- Grass-trees can live up to 600 years
- Some species provide a resin which was used by First Nations people as an adhesive in the manufacture of tools; the stem was also used for the lower part of a spear
- By examining the size of a grass-tree’s ‘skirt’, we can estimate when a fire last occurred; their ability to resprout and produce flowers quickly after fire makes them a vital lifeline for animals living in recently burnt habitat
A reference to its yellow resin, Xanthorrhoea literally means "yellow flow" in Ancient Greek. Grass-tree is a misnomer. Its not a grass, nor a tree.They are actually distantly related to lilies.
Perennial flowering plant. Trunk resembles a tree above ground or exists under the earth’s surface. Trunk is woody and made up of tiny packed leaves.
Leaves
Clustered in a terminal crown, 30 - 140 cm long, rhombic (kite-shaped) to wedge-shaped in cross-section, tapering at the ends.
Flowers
Borne as flower clusters on a cylindrical and spike-like woody axis.
In the bush the flowers could reveal directions, since flowers on the warmer, sunnier side (usually north) of the spike often open before the flowers on the cooler side facing away from the sun.
What to Observe
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Presence
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First fully open single flower along its flower spike (less than 25% of flowers open)
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Full flowering (when 50% or more of the spike is in flower)
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End of flowering (when 95% of the flowers on the spike have faded)
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Not flowering
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Health assessment (add in Additional comments and submit multiple sightings if more than one photo is required)
Grass-tree Health Assessment
Populations of grass-tree have been devastated by Phytophthora cinnamomi (dieback). Symptoms of early Phytophthora infection are the same as drought/climate stress symptoms.
- ALIVE (A): Foliage is green with lots of fresh growth, often some browned (not yellow) foliage hanging down over the trunk/base of the plant but extensive healthy growth prevailing. Some individual leaves may show browning or yellowing, but this is not dominant.
- ALIVE WITH SYMPTOMS (WS): Still has some green foliage. Yellowing or browning (signs of chlorosis) are significant and obvious, possibly some limited fresh new growth. OR Grass-tree is showing mild signs of browning/yellowing. Note that it is important to distinguish between the naturally forming skirt present on un-burnt grass-trees, which is a natural death of old fronds, and the chlorosis of live fronds.
- DEAD (D): Foliage completely brown or absent. Trunk may be decaying, collapsing or a hollow in the ground.
When and Where
When To Look
- Year round
- Flowering occurs 2 - 3 times each year in mature plants and can occur en masse after a fire
Where To Look
- In all Australian states and territories, especially on the east and west coast
- X. australis is widely distributed, in Tasmania, Victoria, NSW, ACT and South Australia
If you are able to identify your grass-tree sighting to species level, you can enter these details in Additional comments.
What Else?
Similar Species
Grass-trees without an emergent stem (young Xanthorroea australis and all Xanthorrea minor) are easily confused with Lomandras and other sedges. Sedges have flat fronds and grow in a fan-shape.
Xanthorrhoea is a genus of about 28 species of flowering plants endemic to Australia. Vegetatively, Xanthorroea species are sometimes difficult to distinguish from each other. Features which are required include trunk height, ratio of length of spike and leaf colour.
- X. australis has a stem up to 3 m long, often branched; its flower spike can be quite long, with its flower-bearing part 110 – 250 cm long; flowering is typically restricted to mass events in the year following fire
- X. resinosa has a stem that is absent or up to 0.6 m long and it’s flower-bearing part is shorter than X. australis, 60 - 120 cm long; at the base of its leaves it produces a yellowish resinous fluid, whereas X. australis produces a red-brown resinous fluid
- X. minor (commonly found at Wilson’s Promontory National Park) has a stem that is almost totally subterranean, branched under ground and its flower-bearing part is shorter, 5 - 30 cm long
- X. glauca found in Central and Northern Victoria can only be reliably distinguished by the longer scape (stem-like flowering stalk of a plant; >65 cm) and pointed to spoon-shaped bracts (modified leaves that surround the flowers); it regularly flowers in the absence of fire
