Wild Yam – Dioscorea villosa,D. spp

Overall At-Risk Score: 41

Latin Name:

Dioscorea villosa (L.); syn: Dioscorea villosa f. glabrifolia (Bartlett)¹

Common Name:

Wild Yam;

Family:

Dioscoreaceae (Yam Family)¹

Geographic Region:

Wild Yam has a large native range encompassing most of the eastern United States, ending at the edge of the great plains:
AL, AR, CT, DC, DE, FL, GA, IA, IL, IN, KS, KY, LA, MA, MD, MI, MN, MO, MS, NC, NE, NJ, NY, OH, OK, PA, RI, SC, TN, TX, VA, WI, WV, and into parts of Southern Ontario²

Habitat:

Found most frequently in open prairies and forest edges. Wild Yam can be found in a range of habitats, from poor quality railroad borders to rare remnant prairies.³

Lifespan:

Perennial;

Reproduction:

D. villosa is a dioecious plant, meaning plants have either all male flowers or all female flowers. On male plants, tiny, pale green flowers develop in tight clusters along the vine. The female flowers are larger, tubular blossoms of similar color. The fruit develops into a three part capsule, with each cell containing a two winged seeds for wind dispersal.³

Ability to withstand disturbance and over harvest:

Able to survive low-intensity fires, often relying on them to maintain their preferred semi-open habitat.³

Status of Endangered/Threatened(by state):

No legal protections for this species exist.

Part of Plant Used/Active Medicinal Compounds:

Root extracts are taken in the form of tea or tinctures, most commonly. Taken by native americans to lessen labor pains, physicians later prescribed it to treat rheumatism and gastrointestinal irritations.

This plant contains diosgenin compounds that are used to produce a variety of modern steroid drugs.

Vulnerability of habitat/changes of habitat quality and availability:

As a generalist plant, habitat quality is not a limiting factor of this species. It thrives in poor conditions and in human-made edge habitats.

Demand and Relative Acreage Needed to Meet Demand:

An increasing demand for this herb has brought the average annual wild-harvested amount of D. villosa to about 35,000 pounds.

Wild Harvesting Impact On Other Species:

Recommendations for industrial and home use:

There is a very limited market for farmed D. villosa meaning that almost all of the product on the market is gathered in the wild. This increasing market can put a serious strain on established populations, and prevent new colonies from establishing.
This plant is very easy to grow at home, and will thrive in often underused edge and transitional habitats.

  1. ITIS Report. Dioscorea villosa.
    https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=43367#null
  2. BONAP. Dioscorea villosa Range Map.
    http://bonap.net/MapGallery/County/Dioscorea%20villosa.png
  3. John Hilty. Illinois Wildflowers. Dioscorea villosa.
    http://www.illinoiswildflowers.info/savanna/plants/wild_yam.html
  4. Steven Foster and James Duke. Peterson Field Guide to Eastern/Central Medicinal Plants and Herbs. Wild Yam. Page 230.
  5. American Herbal Products Association. Tonnage Survey of Select North American Wild-Harvested Plants, 2006-2010. Page 7.
  6. Appalachian Center of Ethnobotanical Studies. Appalachian Plant Monographs series. Dioscorea vilossa L. .
    https://www.frostburg.edu/fsu/assets/File/ACES/Dioscorea%20villosa%20-%20FINAL(3).pdf

wild yam by Tim McCormack sm

Photo Credit Phyzome AKA Tim McCormack