However, so is the poison oak which you do not want to touch. I'm not very allergic to it but some people are and they will wind up in the hospital if they touch it and get the oil onto their skin. Animals don't get this because the hair and fur on their bodies keeps them from getting it.
So, you need to know what it looks like when walking on trails or near streams so you don't have a disaster that lays you up for weeks or months. Some of the worst places to get this is in your genital area (especially for boys or men) or in your eyes. Also, one of the worst problems from it is breathing the smoke from burning poison oak. So, if you burn a lot of poison oak leaves make sure you are upwind and you aren't putting all your neighbors in the hospital by burning it. Because breathing it is one of the worst ways to get this.
My ex-wife used to get this from the coat of our dog or from the kids clothes in the 1980s and we would have to take her to the hospital usually about once a year to get cortisone shots and stuff like that so she could get over it.
First thing is if you have the oil from the leaves on your clothes or body wash them thoroughly. Unless you just have been walking through acres of poison oak (and there are places like this in northern California) you likely will get no more than a patch. The worst cases are usually children who have no knowledge of any of this and this can really get to be a mess and ruin a whole summer for some kids, especially if they get it on genitals or eyes. So, being forewarned is forearmed.
Remember, the leaves right now are not red they are mostly very green and sort of rounded. They don't turn red until late summer or fall usually. There is something similar with leaves with jagged edges that is not poison oak that grows in forests too. Also, it's favorite thing to do is to go up pine trees like a vine and right now there are 75 foot high growths of it up pine trees in the forests now too. Look for it below 3000 feet elevation mostly near water sources and springs and rivers. But, it also shows up almost anywhere on the coast or in the Sierras or Cascades up to about 3000 feet elevation too. So, always be looking for this on trails below 3000 feet elevation in California.
Here is something from Wikipedia on Poison Oak:
- Toxicodendron diversilobum (syn. Rhus diversiloba), commonly named Pacific poison oak or western poison oak, is a woody vine or shrub in the Anacardiaceae ...
Toxicodendron diversilobum
From Wikipedia, the free encyclopediaToxicodendron diversilobum (syn. Rhus diversiloba), commonly named Pacific poison oak[1] or western poison oak, is a woody vine or shrub in the Anacardiaceae (sumac) family. It is widely distributed in western North America, inhabiting conifer and mixed broadleaf forests, woodlands, grasslands, and chaparral biomes.[2] Like other members of the Toxicodendron genus, T. diversilobum causes itching and allergic rashes in many humans after contact by touch or smoke inhalation.Toxicodendron diversilobum
Pacific poison oak
Pacific poison oak (larger leaves) at base of an oak tree Scientific classification Kingdom: Plantae (unranked): Angiosperms (unranked): Eudicots (unranked): Rosids Order: Sapindales Family: Anacardiaceae Genus: Toxicodendron Species: T. diversilobum Binomial name Toxicodendron diversilobum
(Torr. & A.Gray) GreeneSynonyms Rhus diversiloba Torr. & A.Gray
Contents
Distribution
Toxicodendron diversilobum is found in California (also the original name of Los Angeles; Yangna or Iyaanga/poison oak place),[3] the Baja California Peninsula, Nevada, Oregon, Washington, and British Columbia.[4] The related T. pubescens (eastern poison oak) is native to the Southeastern United States. T. diversilobum and T. rydbergii (western poison ivy) hybridize in the Columbia River Gorge area.[5]
Toxicodendron diversilobum is common in various habitats, from mesic riparian zones to xeric chaparral.[6] It thrives in shady and dappled light through full and direct sunlight conditions, at elevations below 5,000 feet (1,500 m).[5] The vining form can climb up large shrub and tree trunks into their canopies. Sometimes it kills the support plant by smothering or breaking it.[5] The plant often occurs in chaparral and woodlands, coastal sage scrub, grasslands, and oak woodlands; and Douglas-fir (Pseudotsuga menzesii), hemlock–Sitka spruce, Sequoia sempervirens (coast redwood), Pinus ponderosa (Ponderosa pine), and mixed evergreen forests.[7]
Description
Toxicodendron diversilobum is extremely variable in growth habit and leaf appearance. It grows as a dense 0.5–4 m (1.6–13.1 ft) tall shrub in open sunlight, a treelike vine 10–30 feet (3.0–9.1 m) and may be more than 100 feet (30 m) long with an 8–20 cm (3.1–7.9 in) trunk, as dense thickets in shaded areas, or any form in between [5][8] It reproduces by spreading rhizomes and by seeds.[2]
The plant is winter deciduous, so that after cold weather sets in, the stems are leafless and bear only the occasional cluster of berries. Without leaves the stems may sometimes be identified by occasional black marks where its milky sap may have oozed and dried.T. diversilobum foliage
The leaves are divided into three (rarely 5, 7, or 9) leaflets, 3.5 to 10 centimetres (1.4 to 3.9 in) long, with scalloped, toothed, or lobed edges.[6] They generally resemble the lobed leaves of a true oak, though tend to be more glossy. Leaves are typically bronze when first unfolding in February to March, bright green in the spring, yellow-green to reddish in the summer, and bright red or pink from late July to October.[5]
White flowers form in the spring, from March to June.[5] If they are fertilized, they develop into greenish-white or tan berries.[6]
Botanist John Howell observed that the toxicity of T. diversilobum obscures its merits:
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- "In spring, the ivory flowers bloom on the sunny hill or in sheltered glade, in summer its fine green leaves contrast refreshingly with dried and tawny grassland, in autumn its colors flame more brilliantly than in any other native, but one great fault, its poisonous juice, nullifies its every other virtue and renders this beautiful shrub the most disparaged of all within our region."[9]
Toxin qualities
Main article: Urushiol-induced contact dermatitisToxicodendron diversilobum leaves and twigs have a surface oil, urushiol, which causes an allergic reaction.[2] It causes contact dermatitis – an immune-mediated skin inflammation – in four-fifths of humans.[10][11] However, most, if not all, will become sensitized over time with repeated or more concentrated exposure to urushiol.
The active components of urushiol have been determined to be unsaturated congeners of 3-heptadecylcatechol with up to three double bonds in an unbranched C17 side chain.[12] In poison ivy, these components are unique in that they contain a -CH2CH2- group in an unbranched alkyl side chain.[13]
Reactions
Toxicodendron diversilobum skin contact first causes itching; then evolves into dermatitis with inflammation, colorless bumps, severe itching, and blistering.[14] In the dormant deciduous seasons the plant can be difficult to recognize, however leafless branches and twigs contact also causes allergic reactions.Urushiol-induced contact dermatitis from poison oak
Urushiol volatilizes when burned, and human exposure to T. diversilobum smoke is extremely hazardous, from wildfires, controlled burns, or disposal fires.[5] The smoke can poison people who thought they were immune.[5] Branches used to toast food over campfires can cause reactions internally and externally.
Urushiol is also found in the skin of mangos, posing a danger to people already sensitized to T. diversilobum when eating the fruit while it is still in the rind.[15][16]
Ecology
Black-tailed deer, mule deer, California ground squirrels, western gray squirrels, and other indigenous fauna feed on the leaves of the plant.[5] It is rich in phosphorus, calcium, and sulfur.[5] Bird species use the berries for food, and utilize the plant structure for shelter.[5] Neither native animals, nor horses, livestock, or canine pets demonstrate reactions to urushiol.[2]
Due to human allergic reactions, T. diversilobum is usually eradicated from gardens and public landscaped areas. It can be a weed in agricultural fields, orchards, and vineyards.[17] It is usually removed by pruning, herbicides, digging out, or a combination.[18]
Uses
Medicinal
Californian Native Americans used the plant's stems and shoots to make baskets, the sap to cure ringworm, and as a poultice of fresh leaves applied to rattlesnake bites.[19] The juice or soot was used as a black dye for sedge basket elements, tattoos, and skin darkening.[19][20]
An infusion of dried roots, or buds eaten in the spring, were taken by some native peoples for an immunity from the plant poisons.[19]
Chumash peoples used T. diversilobum sap to remove warts, corns, and calluses; to cauterize sores; and to stop bleeding.[19] They drank a decoction made from the roots to treat dysentery.[21]
Cultivation
Toxicodendron diversilobum can be a carefully situated component in wildlife gardens, habitat gardens, and natural landscaping.
The plant is used in habitat restoration projects.[5] It can be early stage succession where woodlands have been burned or removed, serving as a nurse plant for other species.
See also
- Toxicodendron pubescens – Eastern poison oak
- Toxicodendron vernix – Poison sumac
- Toxicodendron radicans – Eastern poison ivy
- Toxicodendron rydbergii – Western poison ivy
References
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- "Toxicodendron diversilobum". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 11 December 2015.
- Jan Timbrook (1990). "Ethnobotany of Chumash Indians, California, based on collections by John P. Harrington". Economic Botany 44 (2): 236–253. doi:10.1007/BF02860489. JSTOR 4255231.
Gallery
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Red phase in spring
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Green phase, and flowers
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Berries
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Summer–autumn turning color phase
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Shrub form
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Vine form
External links
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Wikimedia Commons has media related to Toxicodendron diversilobum. |
- U.S. Forest Service information: Toxicodendron diversilobum (Pacific poison oak)
- Calflora Database: Toxicodendron diversilobum (Pacific poison oak)
- Jepson Flora Project: Toxicodendron diversilobum
- American Academy of Dermatology – Poison Oak information
- Western Poison-Oak Photo Gallery
- All about Western poison oak (T. Diversilobum)
- Toxicodendron diversilobum – U.C. Photo gallery
Categories:
- Toxicodendron
- Poisonous plants
- Flora of the West Coast of the United States
- Flora of Baja California
- Flora of British Columbia
- Flora of California
- Flora of Nevada
- Flora of Oregon
- Flora of Washington (state)
- Flora of the Cascade Range
- Flora of the Klamath Mountains
- Flora of the Sierra Nevada (U.S.)
- Natural history of the California chaparral and woodlands
- Natural history of the California Coast Ranges
- Natural history of the Central Valley (California)
- Natural history of the Channel Islands of California
- Natural history of the Mojave Desert
- Natural history of the Peninsular Ranges
- Natural history of the San Francisco Bay Area
- Natural history of the Santa Monica Mountains
- Natural history of the Transverse Ranges
- Plants used in traditional Native American medicine
- Plants described in 1838
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