Dendrocnide moroides aka “gympie gympie”

The Dendrocnide moroides has been said to be the plant with the most excruciating sting in the world- injuring and sometimes killing dogs, horses, and even humans. The species is relatively common in Queensland, and is native to the warm forests of northern Australia; typically growing 1.5-2 meters in height. The plant has large, thin heart-shaped leaves, which are covered in small silica-tipped hairs, which are extremely efficient at penetrating the skin of its victims. Contact with these hairs causes the release of the potent toxin moroidin, which causes the long list of agonising symptoms. One reason why the plant is extremely dangerous is that the hairs are very loosely fitted to the cuticle of the leaf, meaning that with light winds, the hairs can be blown off the plant and cause irritation if it comes into contact with an animal. On case of the sting resulted in suicide, after a man accidently used a leaf as a piece of toilet paper. The hairs of the plant can be embedded in the skin, and can remain there if no appropriate treatment has been given, which results in long-term pain and discomfort, which is one of the reasons why the plant is so feared- as the symptoms can sometimes last for weeks, if not months.

Moroidin is the active chemical in the toxin of the plant, and is a bicyclic octapeptide. Its skeletal formula is shown on the adjacent diagram, and it has a molecular formula of  C₄₇H₆₆N₁₄O_{10. It is made of 9 different amino acids.} 

The recommended treatment for skin exposed to the hairs is applying diluted hydrochloric acid and then pulling out the hairs with a hair removal strip. Tweezers or sticky tape can also be used, but care needs to be taken when removing the hairs, as if broken they will worsen the pain.