The plant has many hollow stinging hairs called trichomes on its leaves and stems, which act like hypodermic needles, injecting histamine and other chemicals that produce a stinging sensation when contacted by humans and other animals.
The plant has many hollow stinging hairs on its leaves and stems, which act like hypodermic needles, injecting toxin. The toxin is a complex substance known to contain formic acid, histamine, and a serotonin, that produce a stinging sensation when contacted by humans and other animals.