Distribution: Chiefly east of the Cascades crest in Washington; British Columbia south to California, east to Oklahoma and the Dakotas.
Habitat: River valleys and sagebrush desert to ponderosa pine forests.
Conservation Status: Not of concern
Strong, woody, dioecious climbing vine to 20 m. long.
Leaves pinnately compound with 5-7 narrowly to broadly ovate-cordate leaflets 3-6 cm. long, coarsely few-toothed or lobed.
Flowers in several-flowered bracteate panicles; sepals 4, creamy white, narrowly oblong-lanceolate, 6-15 mm. long; petals none; staminate flowers without vestigial pistils; pistillate flowers with numerous, sterile stamens.
Achenes hairy; styles persistent, 2.5-5 cm. long.