I think most people are aware that Lantana camara is an extremely toxic plant if ingested. Fewer are aware that it can also cause very toxic symptoms in sensitive individuals just by brushing the leaves. These contain fine spines, invisible to the naked eye, which stick in flesh. The toxin then reacts with sweat on the skin and can cause extremely painful, red lumps which last for several days. If affected, scrape the skin in the affected area with a moderately blunt knife and apply anti-allergy cream. I am going to dig all mine out! - Ian.