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FLIP

FLIP: Florida Invasive Plants

Dioscorea alata

Common Name(s): Winged yam, white yam

Origin

Southeast Asia

Ecological Impact

Naturalized populations increasing in number and size in north Florida, with some strands forming blankets of shingled leaves over native vegatation and even able to cover mature trees (D. Ward, University of Florida, 1997 personal communication). So far reported as disrupting natural-area plant communities, particularly coastal hammocks, in south Florida: Broward, Dade, and Lee counties (EPPC 1996). Listed as a Category I invasive species by Florida Exotic Pest Plant Council and as a noxious weed by Florida Department of Agriculture & Services.

Description

Vigorously twining herbaceous vine, from massive underground tuber. Stems to 10 m (30 ft) or more in length, freely branching above; internodes square in cross section, with corners compressed into “wings,” these often red-purple tinged. Aerial tubers (bulbils) formed in leaf axils (not as freely as in D. bulbifera), elongate, to 10 cm (4 in) x 3 cm (1.2 in), with rough, bumpy surfaces. Leaves long petioled, opposite (often with only 1 leaf persistent); blades to 20 cm (8 in) or more long, narrowly heart shaped, with basal lobes often angular. Flowers small, occasional, male and female arising from leaf axils on separate plants (dioecious species), male flowers in panicles to 30 cm (1 ft) long, female flowers in smaller spikes. Fruit a 3-parted capsule; seeds winged.

Identification Tips

May be confused with D. bulbifera L., which has small or absent underground tubers, more numerous aerial tubers, and alternate leaves (see next pages). Native wild yams D. floridana and D. villosa are infrequent in hammocks and floodplains of north and west Florida, never form aerial tubers, and have leaf blades that are rarely to 15 cm (6 in) long.

History

Introduced to the Americas by Portuguese and Spanish traders in the 1500s. Introduced to Florida for ornament and escaped from cultivation.

Range

As of May 2015, reported in over 30 counties throughout the state of Florida, according to EDDMapS (Early Detection & Distribution Mapping System).

Management Strategies

Do not plant. Remove plant, tubers and root system. 

Photos

Most photos courtesy of the Atlas of Florida Plants; click for additional plant details.

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Florida Invasive Plants