International Union for Conservation of Nature (IUCN)

The International Union for Conservation of Nature (IUCN), founded in 1948 and headquartered in Gland, Switzerland, is the world's oldest environmental organisation, functioning as a neutral forum bringing together governments, NGOs, scientists, business and local communities to develop and implement conservation and sustainable-development policy. Its best-known conservation tool is the IUCN Red List, which evaluates every assessed taxon against a common set of extinction-risk criteria (lettered A through E: population reduction, geographic range, small population size and decline, very small or restricted population, and quantitative analysis) and sorts it into a category. A taxon is classed Extinct (EX) when there is no reasonable doubt the last individual has died, after exhaustive searches across its known/expected habitat and appropriate timing have failed to find one — India's Neuracanthus neesianus is a listed example. Extinct in the Wild (EW) applies to a taxon known to survive only in cultivation, captivity, or as a naturalised population well outside its historic range, as with Ginkgo biloba. Critically Endangered (CR) taxa (such as Euphorbia santapaui, Piper barberi and Syzygium gambelianum) face an extremely high extinction risk in the wild by the assessment criteria; Endangered (EN) taxa (Elaeocarpus venustus, Pogostemon nilagricus, Eugenia singampattiana) face a very high risk; Vulnerable (VU) taxa (Dalbergia latifolia, Santalum album, Chloroxylon sweitenia) face a high risk. Below the threatened tier sit Ne …