Poison ivy in the context of "Toxicodendron vernix"

Toxicodendron vernicifluum (formerly Rhus verniciflua), also known by the common name Chinese lacquer tree, is an Asian tree species of genus Toxicodendron native to China and the Indian subcontinent, and cultivated in regions of China, Japan and Korea. Other common names include poison sumac, Japanese lacquer tree, Japanese sumac, and varnish tree. The trees are cultivated and tapped for their toxic sap, which is used as a highly durable lacquer to make Chinese, Japanese, and Korean lacquerware.

The trees grow up to 20 metres tall with large leaves, each containing from 7 to 19 leaflets (most often 11–13). The sap contains the allergenic compound urushiol, which gets its name from this species' Japanese name urushi (urushi (漆)); "urushi" is also used in English as a collective term for all kinds of Asian lacquerware made from the sap of this and related Asian tree species, as opposed to European "lacquer" or Japanning made from other materials. Urushiol is also the oil found in poison ivy and poison oak that causes a rash.

Toxicodendron is a genus of flowering plants in the sumac family, Anacardiaceae. It contains trees, shrubs and woody vines, including poison ivy, poison oak, and the lacquer tree. The best-known members of the genus in North America are eastern poison ivy (T. radicans) and western poison oak (T. diversilobum), both ubiquitous throughout much of their respective region.

All members of the genus produce the skin-irritating oil urushiol, which can cause a severe allergic reaction known as urushiol-induced contact dermatitis. The resins of certain species native to Japan, China and other Asian countries, such as lacquer tree (T. vernicifluum) and wax tree (T. succedaneum), are used to make lacquer, and, as a byproduct of lacquer manufacture, their berries are used to make japan wax.

Toxicodendron radicans, commonly known as eastern poison ivy or poison ivy, is a species of allergenic flowering plant. It has numerous subtaxons and forms both vines and shrubs. Despite its common name, it is not a true ivy, but rather a member of the cashew and sumac family, Anacardiaceae. It is different from western poison ivy, Toxicodendron rydbergii, and resembles a number of species.

The species is found in North America. Although commonly eaten by animals, with birds consuming the seeds, T. radicans is considered a noxious weed. As a poison ivy, it causes urushiol-induced contact dermatitis in most people who touch it, producing an itchy, irritating, and sometimes painful rash.

Urushiol-induced contact dermatitis (also called Toxicodendron dermatitis or Rhus dermatitis) is a type of allergic contact dermatitis caused by the oil urushiol found in various plants, most notably sumac family species of the genus Toxicodendron: poison ivy, poison oak, poison sumac, and the Chinese lacquer tree. The name is derived from the Japanese word for the sap of the Chinese lacquer tree, urushi. Other plants in the sumac family (including mango, pistachio, the Burmese lacquer tree, the India marking nut tree, and the cashew) also contain urushiol, as do unrelated plants such as Ginkgo biloba.

As is the case with all contact dermatitis, urushiol-induced allergic rashes are a Type IV hypersensitivity reaction, also known as delayed-type hypersensitivity. Symptoms include itching, inflammation, oozing, and, in severe cases, a burning sensation. Additionally, smoke from burning plant matter may be toxic.

Toxicodendron rydbergii, the western poison ivy, is a species of Toxicodendron in the cashew family native to North America. As a poison ivy, it can cause urushiol-induced contact dermatitis.

Toxicodendron orientale (Asian poison ivy) is an East Asian flowering plant in the genus Toxicodendron. It is a poison ivy, which can cause urushiol-induced contact dermatitis.