Foliage
The leaves are alternate proximally but can become opposite as they advance up the vine. They are about 8 in. (20.3 cm) long, wide, and heart to fiddle-shaped (margins three-lobed), with prominent, parallel veins. The petiole base is not clasping. Leaves are usually more rounded when young or on young plants and fiddle-shaped farther along the stem and on older plants. The rounded stems are thin and wiry.

Flowers
The staminate plants may produce small, white flowers annually.

Fruit
The seeds are winged all around, but the chief means of reproduction are aerial, potato-like tubers (bulbils) located at the leaf axils and underground tubers.

Ecological Threat
Dioscorea polystachya can form dense masses of vines that cover and kill native vegetation, including trees, within a variety of moist, disturbed habitats. It was introduced from Asia for ornamental, food, and medicinal purposes and escaped cultivation in the mid-1990s.

Resources

• A Field Guide for the Identification of Invasive Plants in Southern Forests - USDA Forest Service
• Southeast Exotic Pest Plant Council Invasive Plant Manual - SE-EPPC
• Element Stewardship Abstract - The Nature Conservancy
• Weed of the Week - USDA Forest Service
• Plant Invaders of Mid-Atlantic Natural Areas - National Park Service

Selected Images

Maps

Invasive Listing Sources

• Alabama Invasive Plant Council
• City of Ann Arbor Michigan Parks and Recreation
• Georgia Exotic Pest Plant Council - Category 2
• Indiana Invasive Species Council - Invasive Plant List
• Indiana Terrestrial Plant Rule
• Invasive Plant Species of West Virginia
• Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
• Jil Swearingen, personal communication, 2009-2017
• Kentucky Exotic Pest Plant Council - Severe Threat
• Maine Invasive Plants
• Maryland Department of Agriculture's Candidates for Listing of Invasive Plants
• Maryland Department of Natural Resources Policy: Restriction on Planting Exotic Invasive Plants
• Michigan’s Invasive Species Watch List
• Missouri SRISP Species List
• National Park Service, Mid-Atlantic Exotic Plant Management Team Invasive Plant List
• New Hampshire Invasive Species Committee. 2005. Guide to Invasive Upland Plant Species in New Hampshire. New Hampshire Department of Agriculture,  Markets and Food Plant Industry Division and New Hampshire Invasive Species Committee.
• New Jersey Invasive Species Strike Team 2017 Invasive Species List
• New York Regulated and Prohibited Invasive Species - Prohibited
• Non-Native Invasive Plants of Arlington County, Virginia
• Non-Native Invasive Plants of the City of Alexandria, Virginia
• Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
• Ohio Invasive Species Council
• Pennsylvania Department of Conservation and Natural Resources Invasive Plants
• Plant Invaders of Mid-Atlantic Natural Areas
• South Carolina Invasive Pest Council
• Tennessee Exotic Pest Plant Council
• Virginia Invasive Plant Species List
• WeedUS - Database of Plants Invading Natural Areas in the United States
• West Virginia Invasive Species Strategic Plan and Volunteer Guidelines 2014
• West Virginia Native Plant Society, Flora West Virginia Project, and West Virginia Curatorial Database System, September 3, 1999
• Wisconsin Noxious Weeds
• Wisconsin's Invasive species rule – NR 40

References