poison oak

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poison ivy

poison ivy, poison oak, and poison sumac, woody vines and trailing or erect shrubs of the family Anacardiaceae (sumac family), native to North America. They are sometimes considered as several species of Rhus, the sumac genus, but are usually distinguished as Toxicodendron radicans (poison ivy and poison oak) and the larger T. vernix (poison sumac). The whitish berrylike fruits often persist through winter. The leaves of T. radicans are composed of three smooth leaflets. Both species have vivid red autumn foliage. Poison oak is a name generally used in the South and West for the bushy kinds.

The irritant principle, urushiol, is present in almost all parts of the plant. Direct or indirect contact (clothing, tools, or animals that have touched the plant, or smoke from burning the plants) sets off a skin eruption that may vary from simple itching inflammation to watery blisters, depending upon the sensitivity of the individual. The eruption appears within a day to two weeks depending upon sensitivity. It begins on the portion of the body that has come in contact with the plant, usually the hands, which then can spread it to the face and other areas. Washing contaminated skin as soon as possible after contact can reduce the severity of symptoms. These plants are classified in the division Magnoliophyta, class Magnoliopsida, order Sapindales, family Anacardiaceae.

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poison oak

[′pȯiz·ən ′ōk]
Any of several bushy poison ivy plants or shrubby poison sumacs.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Since the launch of Tecnu, Tec Labs has expanded the line to cover ailments ranging from poison oak and poison ivy to insect bites, minor skin irritations, sunburns and more.
Its three-part leaves can have smooth, toothed or lobed edges, often confused with poison oak.
As the blacktail buck vanished in front of me, I remembered my many youthful encounters with poison oak. Even during the leafless November dormant period, this virulent plant has always been my enemy.
Romance, inevitable with mixed gatherings of teens, is featured in young adult stories like Order of the Poison Oak, Sleepaway Girls, Stepping Up, Sunrise, and Born at Midnight.
The same rash can occur after exposure to poison oak, poison ivy, and poison sumac, and sometimes after exposures to mango trees or Ginkgo Biloba.
Add in a little poison oak and brush, and you have the five tons per acre of thinnings from wildfire protection projects in communities across California.
It takes the goats one to two weeks to eat up the brush, star thistle, and poison oak (unlike humans, they're not allergic to it), leaving manicured slopes behind.
HIGH School Musical star Zac Efron has revealed that he suffered a severe allergic reaction to poison oak during a camping trip.
All ours: Wild clumps of poison oak, a lank Rust-eaten,
But it didn't work, bushes closed in, there was poison oak, vines