Mescaline of the genus "Echinopsis" are technically controlled substances under the Controlled Substances Act, they are commonly sold publicly as ornamental plants. In the United Kingdom, mescaline in purified powder form is a Class A drug. However, dried cactus can be bought and sold legally. Mescaline is considered a schedule 9 substance in Australia under the Poisons Standard (October 2015). A schedule 9 substance is classified as "Substances with a high potential for causing harm at low exposure and which require special precautions during manufacture, handling or use. These poisons should be available only to specialised or authorised users who have
Plant ecology an important role in the development of the field of plant ecology during the first half of the twentieth century, among them William S. Cooper, E. Lucy Braun and Edgar Transeau. Plant distributions is governed by a combination of historical factors, ecophysiology and biotic interactions. The set of species that can be present at a given site is limited by historical contingency. In order to show up, a species must either have evolved in an area or dispersed there (either naturally or through human agency), and must not have gone locally extinct. The set of species present locally is further