Chinese yam USDA PLANTS Symbol: DIOP
U.S. Nativity: Exotic
Habit: Vines Forbs/Herbs
Dioscorea polystachya Turcz.

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Taxonomic Rank: Liliopsida: Dioscoreales: Dioscoreaceae
Native Range: Temperate eastern Asia (BAIL);

Appearance
Dioscorea polystachya is an invasive herbaceous, twining vine that grows to about 16.4 ft. (5 m). It invades open to shady areas in the Eastern United States.
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.

Identification, Biology, Control and Management Resources

Selected Images from Invasive.orgView All Images at Invasive.org


Feature(s); Aerial tubers and foliage
Jack Ranney, University of Tennessee, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Great Smoky Mountains National Park Resource Management , USDI National Park Service, Bugwood.org
Additional Resolutions & Image Usage

Infestation;
Chris Evans, University of Illinois, Bugwood.org
Additional Resolutions & Image Usage

Infestation;
Chris Evans, University of Illinois, Bugwood.org
Additional Resolutions & Image Usage

Infestation;
Chris Evans, University of Illinois, Bugwood.org
Additional Resolutions & Image Usage

Foliage;
Chris Evans, University of Illinois, Bugwood.org
Additional Resolutions & Image Usage

Foliage; July
James H. Miller, USDA Forest Service, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Troy Evans, Great Smoky Mountains National Park, Bugwood.org
Additional Resolutions & Image Usage

Seed(s);
Steve Hurst, USDA NRCS PLANTS Database, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s); aerial tubers
Chris Evans, University of Illinois, Bugwood.org
Additional Resolutions & Image Usage

Foliage;
Chris Evans, University of Illinois, Bugwood.org
Additional Resolutions & Image Usage

Feature(s); aerial tubers
Chris Evans, University of Illinois, Bugwood.org
Additional Resolutions & Image Usage

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org
 


State(s) Where Reported invasive.
Based on state level agency and organization lists of invasive plants from WeedUS database.

U.S. National Parks where reported invasive:
Colonial National Historical Park (Virginia)
Great Smoky Mountains National Park (North Carolina & Tennessee)
Harpers Ferry National Historical Park (West Virginia)
Kings Mountain National Military Park (South Carolina)
Rock Creek National Park (Washington, D.C.)
Stones River National Battlefield (Tennessee)



Invasive Listing Sources:
Alabama Invasive Plant Council
Faith Campbell, 1998
Georgia Exotic Pest Plant Council
Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
Jil Swearingen, personal communication, 2009-2016
Kentucky Exotic Pest Plant Council
Maryland Department of Natural Resources, 1994
Mid-Atlantic Exotic Pest Plant Council, 2005
Missouri Department of Conservation,
South Carolina Exotic Pest Plant Council
Tennessee Exotic Pest Plant Council
Tennessee Exotic Pest Plant Council
Virginia Invasive Plant Species List