Page authors: Don Knoke, David Giblin
Toxicodendron radicans
western poison ivy
Specimens
Photos

Distribution: Occurring east of the Cascades crest in Washington; occurring throughout much of North America, except Alaska, California, southeastern U.S. and northeastern Canada.

Habitat: Generally in the lowlands and foothills and into the lower mountains in open areas or forest edges.

Flowers: April-July

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Description:
General:

Somewhat pubescent shrub 0.5-2 m. tall.

Leaves:

Leaves trifoliate; leaflets broadly ovate, pointed, entire to shallowly lobed, 5-15 cm. long.

Flowers:

Inflorescence of congested, axillary panicles; flowers mostly imperfect, dioecious, 2-3 mm. long; calyx 5-parted, about half the length of the petals; petals 5; staminate flowers with 5 exerted stamens, the filaments attached to the rim of a fleshy, flat disk; ovary superior, style 1, stigmas 3.

Fruits:

Fruit drupe-like, glabrous, about 4 mm. long, white, with a greenish or yellowish cast.

Accepted Name:
Toxicodendron radicans (L.) Kuntze
Publication: Revis. Gen. Pl. 1: 153. 1891.

Synonyms & Misapplications:
Rhus radicans L. [HC]
Infraspecies:
var. rydbergii – poison-ivy, western poison-ivy    Occurring east of the Cascades crest in Washington; distributed throughout much of North America, except Alaska, California, southeastern U.S. and northeastern Canada.
Additional Resources:

PNW Herbaria: Specimen records of Toxicodendron radicans in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Toxicodendron radicans checklist entry.

E-Flora BC: Toxicodendron radicans atlas page.

CalPhotos: Toxicodendron radicans photos.

USDA Plants: Toxicodendron radicans information.

30 photographs:
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