Shrubby Western Poison Ivy Botanical Illustrations and Images

Summary: Western poison ivy botanical illustrations and images give distribution ranges, life cycles and looks of eco- and wildlife-tolerant, irritating shrubs.

western poison ivy (Toxicodendron rydbergii) foliage and fruit: Dave Powell, USDA Forest Service (retired), Bugwood.org, CC BY 3.0 United States, via Forestry Images

Western poison ivy botanical illustrations and images apply to western North American provinces, states and territories that, apart from Arizona, eastern poison ivy avoids and to some areas of eastern North America.

Western poison ivy bears its common name for biogeography and the irritating urushiol alkaloids in all body parts even though it belongs among shrubs, not ivies. Its scientific name, Toxicodendron rydbergii, comes from the Greek τοξικός (toxikós, "poison") and δένδρον (déndron, "tree") and commemorates Per Axel Rydberg (July 6, 1860-July 25, 1931). John Kunkel Small's (Jan. 31, 1869-Jan. 20, 1938) and Edward Greene's (Aug. 20, 1843-Nov. 10, 1915) species and Toxicodendron rydbergii var rydbergii subspecies descriptions determine taxonomies.

Western species exist throughout North America, excepting Labrador, Newfoundland and Yukon Territory; and Alabama, Arkansas, California, Florida, Georgia, Kentucky, Louisiana, Mississippi, Missouri, South Carolina and Tennessee.

April through November, April through June and August or September and July through November furnish western poison ivy life cycles with leafing, flowering and fruiting months.

Western poison ivy grows into mature 3.28- to 9.84-foot- (1- to 3-meter-) high and wide shrubs from rhizomes, root crowns and three-month cold-stratified, digestive tract-scarified seeds. It has branching, horizontal rhizomes (from the Greek ῥῐ́ζᾰ, rhíza, "root") with adventitious roots and winter scale-free buds at 3.94- to 5.91-inch (10- to 15-centimeter) depths. The Anacardaceae (from the Greek ἀνά, aná, "upon" and καρδία, kardía, "heart") cashew, pistachio and sumac family member includes downward-growing, fibrous roots through 12.14-foot (3.7-meter) depths.

Western poison ivy botanical illustrations and images juggle acidic to alkaline soil pH ranges of 5.7 to 8.4 up through 8,497.38-foot (2,590-meter) altitudes above sea level.

Western poison ivy keeps three 1- to 6-inch- (2.54- to 15.24-centimeter-) long, 1- to 4-inch- (2.4- to 10.16-centimeter-) wide leaflets on every alternate-attached, smooth-stalked compound leaf.

Tip-pointed leaves with lobed, lobed and toothed or toothed margins look bronze-green when young, glossy when mature, orange- to yellow-red in fall and withered in winter. Plume-like panicles maximally maintain 25 stalked yellow flowers with cup-like, five-lobed, sepal-filled green calyxes (from the Greek κάλυξ, kálux, "husk") for five green-white or white petals. Five white-filamented, yellow-anthered stamens per 0.0625-inch- (1.5875-millimeter-) diameter flower in 2- to 12-inch- (5.08- to 30.48-inch-) long clusters net ants, bees, beetles, butterflies, flies and wasps.

Western poison ivy botanical illustrations and images observe cross-pollinating insects from male-flowering shrubs on the three-lobed stigma atop every female-flowering shrub flowers' single green pollen-receiving pistil.

Globe-like ovaries produce berry-like, grape-clustered, round, 0.125-inch- (3.17-millimeter-) diameter drupes, greening into white with age, each with one 0.12- to 0.16-inch- (3- to 4-millimeter-) diameter seed.

Fruit-questing bears, foxes, deer, mice, moose, muskrats, rabbits, squirrels, woodchucks and woodrats and bobwhites, grouses and wild turkeys respectively queue up additionally for foliage and seeds. They retrieve western poison ivy from ash, aspen, birch, buffaloberry, chokecherry, cottonwood, dogwood, elm, hickory, juniper, maple, oak, pine, red-cedar, snowberry and willow wetlands and woodlands. They survive 15.75- to 61.89-inch (400- to 1,572-millimeter) average annual rainfall and yearly annual temperatures between 39 and 72 degrees Fahrenheit (3.88 and 22.22 degrees Celsius).

Shrubby western poison ivy botanical illustrations and images trip over herb-, shrub-, vine-like eastern counterparts in grasslands, wetlands and woodlands and on roadsides and rocky outcrops.

western poison ivy (Toxicodendron rydbergii); Columbus, Stillwater County, south central Montana; Thursday, Jan. 10, 2002, 13:30:39: USDA NRCS Montana (NRCS Montana), Public Domain, via Flickr

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

western poison ivy (Toxicodendron rydbergii) foliage and fruit: Dave Powell, USDA Forest Service (retired), Bugwood.org, CC BY 3.0 United States, via Forestry Images @ https://www.forestryimages.org/browse/detail.cfm?imgnum=1208035

western poison ivy (Toxicodendron rydbergii); Columbus, Stillwater County, south central Montana; Thursday, Jan. 10, 2002, 13:30:39: USDA NRCS Montana (NRCS Montana), Public Domain, via Flickr @ https://www.flickr.com/photos/160831427@N06/38880846341/

For further information:

Darlington, Joan Raysor. 1999. Is It Poison Ivy? Durham NH: Oyster River Press.

Greene, Edward Lee. 24 November 1905. "T. Rydbergii." Leaflets of Botanical Observation and Criticism, vol. I: 117.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/396243

"Rhus rydbergii Small ex Rydb." Tropicos® > Name Search.
Available @ http://www.tropicos.org/Name/50075056

Rydberg, Per Axel. 15 February 1900. "Catalogue of the flora of Montana and the Yellowstone National Park: Rhus rydbergii Small." Memoirs of the New York Botanical Garden, vol. I: 268-269.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/7418162

"Toxicodendron rydbergii (Small ex Rydb.) Greene." Tropicos® > Name Search.
Available @ http://www.tropicos.org/Name/1300274