The rain forests of the world are vital for many reasons, not the least of which is that they affect climate systems around the planet and are home to a number of indigenous peoples. They are also the location of a huge variety of plant species, many of which are not found anywhere else, and some of which are poisonous.
A poisonous plants to be avoided is the stinging tree, Dendrocnide moroides, that is found in the rain forests of northeastern Australia, Indonesia and other island groups in the region. Growing in size from 3 feet to 4 feet, with large, heart-shaped leaves, the stinging tree is covered in fine hairs that can penetrate the skin and deliver a powerful toxin that can be fatal for humans and other creatures.
More commonly known by names such as "elephant ear," "heart of Jesus" and "angel wings," caladium is a member of the Araceae family of plants. Native to Brazil and neighboring areas in the Amazon rain forest, the entire plant is poisonous. Eating any part of it can cause serious illness, and even touching it may cause irritation to the skin. The two principal species are known as fancy-leaf and lance-leaf because of their color and shape.
Probably the best known of the Amazon rain forest's toxic plants is curare. It has long been used by the indigenous peoples as a poison into which arrows are dipped prior to being fired from blowpipes. It brings down prey by paralyzing victims after it has shut down the respiratory system. However, people of the Amazon basin also use it for medicinal purposes, particularly as an anesthetic, although it can kill as easily as it can cure.
Strychnos is the flowering plant from which the poison strychnine is derived. Native to tropical parts of Asia, there are a number of different species and it can also be found in southern Africa and South America. One of the most toxic varieties is Strychnos toxifera, a liana that can grow more than 30 feet long and produces bitter red fruit. A poison used by native people is made from the tree bark.