Dendrocnide moroides

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Dendrocnide moroides
File:Stinging tree.JPG
Scientific classification
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Species:
D. moroides
Binomial name
Dendrocnide moroides

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Dendrocnide moroides, also known as the stinging bush, gympie stinger, mulberry-leaved stinger, gympie gympie, gympie,[1] stinger, the suicide plant, or moonlighter, is a large shrub native to rainforest areas in the northern half of eastern Australia, the Moluccas and Indonesia.[2]:{{{3}}}[3]:{{{3}}}[4]:{{{3}}} It is best known for stinging hairs that cover the whole plant and deliver a potent neurotoxin when touched. It is the most toxic of the Australian species of stinging trees.[2]:{{{3}}}[4]:{{{3}}} The fruit is edible if the stinging hairs that cover it are removed.[5]

D. moroides usually grows as a single-stemmed plant reaching 1–3 metres in height. It has large, heart-shaped leaves about 12–22 cm long and 11–18 cm wide, with finely toothed margins.

Ecology

The species is unique in the genus Dendrocnide in having monoecious inflorescences in which the few male flowers are surrounded by female flowers.[4]:{{{3}}} The flowers are small, and once pollinated, the stalk swells to form the fruit. Fruits are juicy, mulberry-like, and are bright pink to purple. Each fruit contains a single seed on the outside of the fruit.[6]:{{{3}}}

The species is an early coloniser in rainforest gaps; seeds germinate in full sunlight[7] after soil disturbance. Although relatively common in Queensland, the species is uncommon in its southern-most range, and is listed as an endangered species in New South Wales.[3]:{{{3}}}[8]:{{{3}}}

The giant stinging tree and the shining-leaved stinging tree are other large trees in the nettle family occurring in Australia.

Toxicity

Contact with the leaves or twigs causes the hollow, silica-tipped hairs to penetrate the skin. The sting causes an extremely painful stinging sensation that can last for days, weeks, or months, and the injured area becomes covered with small, red spots joining together to form a red, swollen mass. The sting is potent enough to kill humans, dogs, and horses,[6]:{{{3}}} and is infamously agonizing. Stories tell of horses jumping off cliffs after being stung, and supposedly one Australian officer shot himself to escape the pain of a sting.[9]:{{{3}}} One man who was slapped in the face and torso with the foliage said, "For two or three days the pain was almost unbearable; I couldn’t work or sleep, then it was pretty bad pain for another fortnight or so. The stinging persisted for two years and recurred every time I had a cold shower. ... There's nothing to rival it; it's ten times worse than anything else."[9]:{{{3}}}

However, the sting does not stop several small marsupial species, including the red-legged pademelon, insects and birds from eating the leaves.[6]:{{{3}}} Moroidin, a bicyclic octapeptide containing an unusual C-N linkage between tryptophan and histidine, was first isolated from the leaves and stalks of Dendrocnide moroides, and subsequently shown to be the principal compound responsible for the long duration of the stings.[10]:{{{3}}}

There has been anecdotal evidence of some plants having no sting, but still possessing the hairs, suggesting a chemical change to the toxin.[11]:{{{3}}}

Treatment

The recommended treatment for skin exposure to the hairs is applying diluted hydrochloric acid (1:10) [12]:{{{3}}} and pulling them out with a hair removal strip.[13]:{{{3}}}[14]:{{{3}}}

Cases

Research scientist Marina Hurley spent three years studying the stinging trees in the Atherton Tableland (Queensland), wearing protective clothing. Her initial symptoms lasted for hours and involved sneezing fits, watering eyes and a runny nose, but the allergy became more severe with repeated exposure. In one incident she had to be hospitalized. Her extreme itching and urticaria required steroid treatment.[9]:{{{3}}}

References

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  7. If You Touch This Plant It Will Make You Vomit In Pure Agony
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  9. 9.0 9.1 9.2 "Once Stung, never Forgotten", Australian Geographic
  10. proseanet.org: Dendrocnide
  11. "Gympie-Gympie losing its sting?", Australian Geographic
  12. "Gympie-Gympie Factsheet", Australian Geographic
  13. "Stinging Trees", Karl S. Kruszelnicki, ABS Science, abc.net.au
  14. "Stinging Trees - and a NEW Treatment for stings", Cape Tribulation Tropical Research Station

Further reading

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External links