Few plants can strike fear into the hearts of locals and visitors alike more than the stinging tree or Gympie-Gympie. Its beautiful fuzzy heart-shaped leaves look harmless, until you touch them. Then you instantly come to know this plants sinister dark side.
It belongs to a family of plants known as Urticaceae and the Gympie-Gympie is one of four members of this family found in Australia. The other three species are the Giant Stinging Tree (dendrocnide excelsa) the Shiny Leaf Stinging Tree (dendrocnide photinophylla) and the Atherton Tableland Stinging Tree (dendrocnide cordata).
The Gympie-Gympie is a soft-wooded shrub that can grow to 4 or 5 meters tall, but is at its most dangerous when 10cm to 1m when it is easier to brush against. The Atherton Tableland Stinger is the most similar species; the other two grow to be trees over 20m tall but the Gympie-Gympie has the worst sting of any plant in Australia.
They have broad oval to heart-shaped leaves covered in stinging hairs giving them a fuzzy appearance the edges of the leaves are saw-toothed and the fruit is mulberry like and white to reddish purple. Both stems and fruit coated with stinging hairs.
Although mostly found in the tropics they are able to grow further south in northern New South Wales, but are mainly found from Gympie in south east Queensland to Cape York Peninsula north Queensland. They are very common on the Atherton Tablelands and seem to prefer highland to lowland rainforest. They often sprout up in large numbers after disturbances to the forest such as cyclones and land clearing, preferring to grow in places that are sunny but protected from the wind like creek edges, walking tracks and roadsides through the forest.
The stinging hairs are made of silica and break off when touched acting like tiny needles causing intense pain. Almost immediately there is whitening of the skin and swelling at the site of the sting sometimes followed by profuse sweating. Although chemical make-up of the toxin is not completely understood. It contains a peptide (called moroidin, also the species name) that coats the hairs and may be responsible for the intensity of the pain. Once embedded in the skin the pain is long- term, lasting for months and reoccurring with changes in temperature or rubbing of the affected area. Leaves can even sting long after they are dead. People have received stings from specimens examined in museums some more than one hundred years old. Hairs seal in the toxin in what could be likened to little glass vials that are unaffected by age.
If you are unlucky and receive a sting from a Gympie-Gympie tree unfortunately, there is not a lot you can do about it. No antidote exists. The best thing you can do is use a diluted hydrochloric acid solution of 1:10 by volume to try to neutralize the peptide coating on the hair. Followed by waxing strips to remove the hairs. It is still going to hurt like hell, but it will reduce the time and severity of the ordeal. Some people say that the root of the Cunjevoi plant that is sometimes found growing nearby can offer relief. However, it has proven to be ineffective and seems to make the pain worse.
The fruit of the tree is actually edible but it has a very bland taste not worth all the effort of gathering, removing the hairs and risking a sting. Birds eat the fruit and spread the seeds and some insects can even eat the leaves.