NATIVE RANGE: North America

FIRST FINDING IN SLOVENIA: 1900

PATHWAYS: horticulture; spread as a hitchhiker on agricultural vehicles. 

POSSIBLE TO FIND: year-round

FLOWERING SEASON: July-September

DESCRIPTION: Annual vine with branched tendrils opposite each leaf. The stem is pale green and covered with hairs. Leaves are alternate, palmately compound, with a slightly serrated margin. Leaves are glabrous above, finely pubescent below, especially along the veins on the underside. Flowers monoecious, small (up to 1 cm), greenish-yellow and borne in racemes. Fruits are oval capsules 1.5 cm long, in clusters of up to 10, covered with bristly, hairy spines and each contain just one seed.

HABITAT: Fertile and moist habitats, especially in flood-plains, wet meadows, but also in scrubland, clearings, along ditches, roadsides and forest edges.

STATUS: Established in Northern Italy and parts of Poland. Scattered observations in the rest of Europe. Found locally in the Alpine and Pannonian parts of Slovenia. 

SIMILAR SPECIES: Wild cucumber (Echinocystis lobata), has hairless stems, deeply lobed leaves, and white to greenish dioecious flowers, which are borne in upright clusters. Its fruit is a large, egg-shaped pepo up to 6 cm long, covered with soft, pointed, green spines. Similar in growth habit are the black-berried white bryony (Bryonia alba), and red bryony (B. dioica) which bears red berries.

SOURCE: Field Guide to Invasive Alien Species in European Forests