| Poison sumac | |
|---|---|
 | |
| Poison sumac leaves | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Sapindales |
| Family: | Anacardiaceae |
| Genus: | Toxicodendron |
| Species: | T. vernix |
| Binomial name | |
| Toxicodendron vernix | |
 | |
| Synonyms[3] | |
List
| |
Toxicodendron vernix, commonly known aspoison sumac,[4] orswamp-sumach,[5] is a woodyshrub or small tree growing to 9 metres (30 feet) tall.[6][7] It was previously known asRhus vernix. This plant is also known asthunderwood, particularly where it occurs in the southern United States.
Like its toxic relativespoison ivy andpoison oak, all parts of the plant contain aresin calledurushiol, which causes skin and mucous membrane irritation to humans. When the plant is burned, inhalation of the smoke may cause the rash to appear on the lining of the lungs, causing extreme pain and possibly fatal respiratory difficulty.
Poison sumac is a shrub or small tree, growing up to nearly 9 metres (30 feet) in height. Eachpinnate leaf has 7–13 leaflets, each of which is 5–10 centimetres (2–4 inches) long. These are oval-to-oblong;acuminate (tapering to a sharp point);cuneate (wedge-shaped) at the base; undulate (wavy-edged); with an underside that isglabrous (hairless) or slightlypubescent (down-like hair) beneath. The stems along the leaflets are red and the leaves can have a reddish tint to them, particularly at the top of the plant. New bark for a poison sumac tree is lightish gray, and as the bark ages, it becomes darker.
Its flowers are greenish, growing in loose axillarypanicles (clusters) 8–20 cm (3–8 in) long. The fruits aresubglobose (not quite spherical), whitish-gray, flattened, and about 0.5 cm (1⁄4 in) across; these are eaten by birds.[8]
Poison sumac fruit are creamy white and part of a cluster. Typically, they are around4 to 5 millimetres (5⁄32 to3⁄16 in) in size.
Poison sumac grows exclusively in wet and clay soils, usually inswamps and peatbogs, in the easternUnited States and extreme southeastCanada.[4]
The fruit and leaves of the poison sumac plant contain urushiol, an oil that causes an allergic rash upon contact with skin. They are, however, not toxic to birds or other animals, and eaten by them when other food is scarce, especially in winter.[9]
In terms of its potential to cause urushiol-induced contact dermatitis, poison sumac is more toxic than its relativespoison ivy andpoison oak.
The differences in toxicity in poison ivy, poison oak, and poison sumac are due to differences in theside chains of the chemicals in these plants. In general, poison ivy has a C15 side chain, poison oak has a C17 side chain and poison sumac has a C13 side chain.
The dermatitis shows itself in painful and long continued swellings and eruptions.[6] In the worst case, smoke inhaled by burning poison sumac leads to life-threateningpulmonary edema whereby fluid enters thealveoli.[10]
