As well as discovering new native species, taxonomists play a critical role in identifying and documenting introduced species in Australia, including new weeds and pests.
When a new, weedy-looking plant turned up on a construction site at the Ranger uranium mine rehabilitation area in Kakadu National Park recently, local botanists were perplexed. They had never seen anything like it before, and couldn't assign it to a plant family, let alone a species.
Fortunately, they promptly sent specimens to Ian Cowie at the Northern Territory Herbarium. At first, even Ian (who probably knows more about the plants of the Northern Territory than anyone alive) was stumped. But some careful botanical detective work led him to identify it as the first Australian record of the West Indian Pink (Spigelia anthelmia).
This species is native to South and Central America from Brazil and Peru to Mexico. It's spread as a weed throughout the world's tropics.
Spigelia anthelmia is highly toxic both to people and stock, causing dizziness, delirium, dilation of the pupils, vomiting and convulsions, sometimes leading to death. It's even been used in criminal poisonings overseas. Not the sort of plant we want in Australia, for many reasons.
Prompt identification has allowed prompt action. The infestation has been sprayed, with an intention to eradicate it. The weed appears to be restricted to a small area that was used to store pre-fabricated building materials shipped from the Philippines, where the species is a common weed. It should be eradicable.
In a nice twist, characteristic black leaf-spots on the plants may be signs of infection by a non-native strain of the fungus Cercospora apii. So eradication of the population may be able to kill two birds with one stone, and prevent two potentially serious new incursions into Australia.