Naomi Lewis has given birth to four children, but nothing prepared her for the excruciating and long-lasting pain of an encounter with a venomous stinging tree in Queensland’s far north. She was mountain biking at Smithfield, near her Cairns home, when she came off her bike, left the trail and hurtled down an embankment, sliding into a stinging tree, known colloquially as a Gympie-Gympie plant.