Dendrocnide moroides, also known as the stinging brush, mulberry-leaved stinger, gympie gympie, gympie, gympie stinger, stinger, the suicide plant, or moonlighter, is a plant common to rainforest areas in the north east of Australia.  It is also found in Indonesia. It has stinging hairs which cover the whole plant and deliver a potent neurotoxin when touched. It is the most toxic of the Australian species of stinging trees. The fruit is edible to humans if the stinging hairs that cover it are removed.
D. moroides usually grows as a single-stemmed plant reaching 1–3 m (3–10 ft) in height. It has large, heart-shaped leaves about 12–22 cm (5–9 in) long and 11–18 cm (4–7 in) wide, with finely toothed margins.
The species is unique in the genus Dendrocnide in having monoecious inflorescences in which the few male flowers are surrounded by female flowers. 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.
The species is an early coloniser in rainforest gaps; seeds germinate in full sunlight after soil disturbance. Although relatively common in Queensland, the species is uncommon in its southernmost range, and is listed as an endangered species in New South Wales.
Contact with the leaves or twigs causes the hollow, silica-tipped hairs to penetrate the skin. The hairs cause an extremely painful stinging sensation that could last from several hours to 1–2 days, recurring to a lessening degree for several months or more whenever the area is touched, exposed to water, or subjected to temperature change. The injured area becomes covered with small, red spots joining together to form a red, swollen welt. The hairs are also believed to be released to the air when the plant is cut or cleared in large areas. Workers without respiratory protection have reported sneezing, runny noses, mild nasal bleeding and throat irritation while cutting or clearing. Ernie Rider, who was slapped in the face and torso with the foliage in 1963, 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.
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.
There has been anecdotal evidence of some plants having no sting, but still possessing the hairs, suggesting a chemical change to the toxin.
The recommended treatment for skin exposed to the hairs is to apply diluted hydrochloric acid (1:10) and to remove the hairs with a hair removal strip. If this is unavailable, a strip of adhesive tape or tweezers may be used. Broken hair tips, if they remain buried, will continue to cause pain.
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- If You Touch This Plant It Will Make You Vomit In Pure Agony
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- "Once Stung, never Forgotten", Australian Geographic
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- Stewart, Amy (2009). Wicked Plants: The Weed that Killed Lincoln's Mother and Other Botanical Atrocities. Etchings by Briony Morrow-Cribbs. Illustrations by Jonathon Rosen. Algonquin Books of Chapel Hill. ISBN 978-1-56512-683-1.
|Wikimedia Commons has media related to Dendrocnide moroides.|
- Dendrocnide at Department of Biology, Davidson College
- Being Stung by the Gympie Gympie Tree Is One of the Worst Kinds of Pain You Can Imagine (2015-01-23), Oddity Central