Toxicodendron diversilobum

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Toxicodendron diversilobum
Toxicodendron diversilobum (larger leaves) at the foot of an oak

Toxicodendron diversilobum (larger leaves) at the foot of an oak

Systematics
Class : Bedecktsamer (Magnoliopsida)
Rosids
Order : Sapindales (Sapindales)
Family : Sumac family (Anacardiaceae)
Genre : Toxicodendron
Type : Toxicodendron diversilobum
Scientific name
Toxicodendron diversilobum
( Torr. & A. Gray ) Greene

Toxicodendron diversilobum (( Torr. & A.Gray ) Greene ; Syn .: Rhus diversiloba Torr. & A.Gray ) is a species of the genus Toxicodendron within the sumac family(Anacardiaceae). Common English names are English Pacific poison oak, and Western poison oak . It is widespread in western North America. It inhabits coniferous and mixed deciduous forests, forest and grasslands as well as the chaparral . The flowering wedding is in May. Like other species of the genus Toxicodendron , the species causes itching and allergenic rashes in many people after coming into contact with parts of plants or inhaling the smoke released during combustion.

description

Vegetative characteristics

Toxicodendron diversilobum is extremely variable in terms of the habitat and the appearance of the leaves. In the blazing sun it appears as a dense, 0.5 to 4 meter high shrub , while in the shade or in dense bushes as a tree-like, often woody climbing plant , it can reach a height of 3 to 10 meters and be more than 30 meters long. The trunk is then 8 to 20 cm in diameter. He can also develop all possible intermediate forms.

Deciduous leaves in autumn; Samuel P. Taylor State Park, California

Toxicodendron diversilobum sheds its leaves in winter, so that the shoot axes are leafless after the onset of cold weather. Only now and then do groups of ripe fruits sit on the sprouts. Leafless shoots can occasionally be recognized by the occasional black mark that occurs when the milky sap emerges and dries.

The long-stemmed leaves are usually pinnate with three (to five, rarely seven) leathery, almost bare leaves . Sometimes the leaves are pinnate. The leaflets or leaf lobes are ovate to obovate and 3.5 to 12 centimeters long, they have entire to roughly toothed or often round to pointed teeth or lobed to divided. They generally resemble the lobed leaves of a real oak , but are rather smooth or shiny. When unfolding in February to March, the leaves are typically bronze-colored, light green in spring, yellow-green to reddish in summer and bright red or pink from late July to October.

The following important information is missing from this article or section:
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Generative characteristics

Toxicodendron diversilobum is mostly dioecious dioecious . Smaller, axillary and loose panicles are formed. The very small, green-white or yellowish, stalked and functionally unisexual flowers with a double bloom unfold in spring from March to June. The small, leathery and bald to fine-bristled, slightly ribbed stone fruit is white-yellowish to brownish when ripe.

The number of chromosomes is 2n = 30.

Quotes

Botanist John Howell found that the toxicity of Toxicodendron diversilobum obscures its worth:

“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. "
“In spring the ivory-colored flowers bloom on the sunny hill or in sheltered clearings, in summer the tender green leaves contrast refreshingly with the dry, yellow-brown grassland, in autumn the colors are more brilliant than any other native plant, just a major flaw poisonous sap, destroys any other value and makes this beautiful shrub the pariah in our area. "

gallery

  • Red phase in spring

  • Green phase, with flowers

  • fruit

  • Color change phase in summer / autumn

  • Shrub shape

  • Climbing form

ecology

Toxicodendron diversilobum reproduces via rhizomes and seeds.

Black- tailed deer , mule deer , California ground squirrels , western gray squirrels, and other native animals eat the leaves of the plant, which is high in phosphorus, calcium, and sulfur. Birds eat the berries and use the entire plant as protection. Neither the native animals nor horses, cattle or domestic rabbits show any reactions to the urushiole.

Because of the allergic reactions caused in humans, Toxicodendron diversilobum is usually removed from gardens and public green spaces. The species can become weeds on agricultural land, in orchards and vineyards . Removal is usually done by pruning, herbicides , digging, or a combination of these measures.

Toxicity

The leaves and branches of Toxicodendron diversilobum have a surface oil (an urushiol ) that causes an allergic reaction . It causes contact dermatitis - a skin irritation mediated by the immune system - in four fifths of all people . However, most (if not all) will become sensitized to the urushiol over time from repeated or concentrated exposure to the poison.

The active components of urushiol have been identified as unsaturated derivatives of 3-heptadecylcatechol with up to three double bonds in an unbranched C17 side chain. These components are unique within poison oak due to a -CH2CH2- group in an unbranched alkyl side chain.

Reactions

Urushiol -induced contact dermatitis , caused by Toxicodendron diversilobum

The main direct contact with Toxicodendron diversilobum initially causes itching; this develops into dermatitis with skin irritation, colorless bumps, severe itching and blistering. It is difficult to identify the plant during periods of rest without foliage, but contact with the leafless branches and twigs can also cause allergic reactions.

Urushiole evaporate in the heat. Human contact with the smoke produced by forest fires, controlled fires, and "disposal" fires is extremely dangerous. The smoke can kill people with supposed immunity. Fires kindled for roasting food with the help of the branches can trigger internal and external reactions.

Urushiols are also found in the skin of mangoes and pose a threat to people who are already sensitive to T. diversilobum if they eat the fruit while the poison is still in the skin.

Occurrence

Toxicodendron diversilobum is spread over California (Los Angeles was built on the site of a village called Yangna or iyaanga ', which means "poison oak place"), the Baja California peninsula , Nevada , Oregon , Washington and British Columbia . The related T. pubescens ( oak-leaved poison oak , English eastern poison oak ) is native to the southeastern United States. T. diversilobum and T. rydbergii ( English western poison ivy ) hybridize in the Columbia River Gorge area .

Toxicodendron diversilobum is widespread in various habitats from fresh alluvial forests to dry chaparral . It thrives in shady, partially shaded, and sunny conditions at elevations below 5,000 ft (about 1,500 m). The climbing form can climb large shrubs and trees up to the crown. Occasionally the climbing foundation is killed by suffocation or breakage. Toxicodendron diversilobum is often in California chaparral and woodlands, shrub steppes on the coast, grasslands spread and Californian oak forests, as well as in forests with Douglas fir ( Pseudotsuga menzesii ), hemlock and Sitka spruce, coastal redwood ( Sequoia sempervirens ), ponderosa pines ( Pinus ponderosa ) as well as in California's evergreen mixed forests.

use

medicine

The Californian Indians used the stem axes of the plants for basket weaving, the plant sap for the treatment of dermatophytosis and the fresh leaves as a medicinal plaster for rattlesnake bites. A juice or brew was used as a black coloring agent for sedge baskets, tattoos and flat skin coloring.

An infusion made in spring from dried roots or buds was drunk by some tribes in order to become "immune" to the plant toxins.

The Chumash tribes used the juice of T. diversilobum to remove warts, corns and calluses, cauterize ulcers and stop bleeding. They drank a decoction made from the roots for dysentery .

Cultivation

Toxicodendron diversilobum can be a carefully placed part of natural gardens and landscaping.

Toxicodendron diversilobum is used in renaturation projects. It can represent an early stage of succession for forest areas where they have been burned down or removed. In this case it serves as a protective planting before other species settle.

Individual evidence

  1. ↑ a b Toxicodendron diversilobum . United States Department of Agriculture, Natural Resources Conservation Service. Retrieved December 11, 2015.
  2. ↑ a b c d C. Michael Hogan: Western poison-oak: Toxicodendron diversilobum " . In: GlobalTwitcher . Nicklas Strömberg. 2008. Archived from the original on July 21, 2009.
  3. ↑ Toxicodendron diversilobum . iNaturalist. Retrieved May 27, 2019.
  4. ↑ a b c d e f g h i j k Toxicodendron diversilobum . US Forest Service . Retrieved May 27, 2019.
  5. ↑ a b c Toxicodendron diversilobum Western poison oak . In: The Jepson Herbarium . University of California , Berkeley. Retrieved May 27, 2019.
  6. ^ John Thomas Howell, Frank Almeda, Wilma Follette, Catherine Best: Marin Flora . California Academy of Sciences; California Native Plant Society, 2007, ISBN 0-940228-70-X , p. 264.
  7. ↑ Pacific poison oak ( Toxicodendron diversilobum ) . In: UC Integrated Pest Management Weed Photo Gallery and information . University of California. Retrieved May 28, 2019.
  8. ↑ Sunset Western Garden Book , 5th Edition, Sunset Publishing, Menlo Park 1988.
  9. ↑ RS Kalish, JA Wood, A. LaPorte: Processing of urushiol (poison ivy) hapten by both endogenous and exogenous pathways for presentation to T cells in vitro . In: Journal of Clinical Investigation . 93, No. 5, 1994, pp. 2039-2047. doi : 10.1172 / jci117198 .
  10. ↑ Contact Poisonous Plants of the World . Mic-ro.com. Retrieved May 27, 2019.
  11. ↑ Michael D. Corbett, Stephen Billets: Characterization of poison oak urushiol . In: Journal of Pharmaceutical Sciences . 64, No. 10, 1975, pp. 1715-1718. doi : 10.1002 / jps.2600641032 .
  12. ↑ John C. Craig, Coy W. Waller, Stephen Billets, Mahmoud A. Elsohly: New GLC analysis of urushiol congeners in different plant parts of poison ivy, Toxicodendron radicans . In: Journal of Pharmaceutical Sciences . 67, No. 4, 1978, pp. 483-485. doi : 10.1002 / jps.2600670411 .
  13. ^ Poison Ivy, Oak & Sumac Information Center . Retrieved May 27, 2019.
  14. ↑ Klilah Hershko, Ido Weinberg, Arieh Ingber: Exploring the mango-poison ivy connection: the riddle of discriminative plant dermatitis . In: Contact Dermatitis . 52, No. 1, 2005, ISSN  0105-1873 , pp. 3-5. doi : 10.1111 / j.0105-1873.2005.00454.x .
  15. ↑ Jane E. Brody: Steering Clear of Poison Ivy . June 16, 2014. Retrieved January 11, 2016.
  16. ↑ Ron Sullivan: Roots of native names . In: San Francisco Chronicle , December 7, 2002. Retrieved June 20, 2017. 
  17. ↑ Toxicodendron diversilobum (Pacific poison oak) . In: Calflora Database . Retrieved May 27, 2019.
  18. ↑ a b c d Toxicodendron diversilobum (Torr. & Gray) Greene . In: Native American Ethnobotany Database . Univ. of Michigan, Dearborn. Retrieved May 28, 2019.
  19. ↑ C. Eugene Conrad: Common shrubs of chaparral and associated ecosystems of southern California  (= Gen. Tech. Rep.), Volume PSW-99. US Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station, Berkeley, CA 1987, p. 86.
  20. ↑ Jan Timbrook: Ethnobotany of Chumash Indians, California, based on collections by John P. Harrington . In: Economic Botany . 44, No. 2, 1990, pp. 236-253. doi : 10.1007 / BF02860489 .

Web links

Commons : Toxicodendron diversilobum  - album with pictures, videos and audio files