by Juliet Bodycomb
Acacia paradoxa, known by the common name, ‘kangaroo thorn’, is a native Australian shrub, known for its dense, prickly foliage.
Growing two to four metres tall, it can be found in G.S. Kingston Park / Wirrarninthi (Park 23), Golden Wattle Park / Mirnu Wirra (Park 21W), Carriageway Park / Tuthangga (Park 17), and Victoria Park / Pakapakanthi (Park 16).
It can be recognised by its curved, leaf-like structures – flattened stalks, called ‘phyllodes’, that likely evolved to conserve water in arid climates. These are attached to thorned branches which, from August to November, boast bright yellow, ball-shaped flowers.
Acacia paradoxa in flower. Photo: Tangey/iNaturalist.
In Australia, kangaroo thorn has been commonly planted for hedges or roadside planting. However, in Your Park Lands, its dense thickets provide nesting sites for small mammals and birds, which are secure from predators like foxes and feral cats.
It also provides food to moths, butterflies, and other insects, as well as birds that eat the seeds.
Acacia paradoxa.
Kangaroo thorn often succeeds in sunny, temperate woodlands and open forests. However, it has a wide environmental tolerance, often withstanding water, drought, and salt-laden winds.
Its tough, long-living seed pods also enable it to be among the first to regenerate after a bushfire.
Acacia paradoxa seed pods. Photo: Trees for Life (SA).
The ants of Your Park Lands share a special relationship with kangaroo thorn. Ants are attracted to the nutritious sac on the end of the seed, called the ‘elaiosome’, which they harvest and bring back to their colony.
After consuming the protein-filled appendage, the unconsumable seed is discarded (often right next to the ant mound), and when the conditions are just right, up sprouts a seedling! This form of seed dispersal, called ‘myrmecochory’, is common among Acacia species.
Want to know more about the plants in your Park Lands? Head over to iNaturalist where you can record, share, and discuss your findings with fellow naturalists.
See the other plants featured in this series here:
https://www.adelaide-parklands.asn.au/know-your-park-lands-plants
Main photo: drmobs/iNaturalist Australia.
