Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to Idaho, Utah, and Arizona, east across much of North America to the Atlantic Coast.

Habitat: Moist bottomlands and thickets.

Flowers: July-September

Origin: Introduced from central and eastern North America

Growth Duration: Annual

Conservation Status: Not of concern

High-climbing, annual vine, monoecious, with branched tendrils.

Leaves alternate, simple, petiolate, 5-15 cm. long, slightly rough, palmately 5-lobed, the triangular-acute lobes remotely toothed.

The staminate flowers in few-flowered, narrow panicles on short peduncles from the leaf axils; the pistillate flowers usually solitary from the same axils; corolla with a short tube and 6 spreading, narrowly lanceolate lobes 3-6 mm. long and 1 mm. wide; sepals 6, small and bristle-like, inserted in the sinuses of the corolla; stamens 3, ovary 2-celled.

Fruit bladdery-inflated, 3.5-5 cm. long, weakly spiny; seeds flattened, ovate, 1.5 cm. long.