Wild Yam, Colic Root

Dioscorea villosa

dy-oh-SKOR-ee-uh  vil-OH-suh

Synonyms of Dioscorea villosa (27) (Updated on 12-16-23 from Plants of the World Online): Dioscorea cliffortiana Lam. (1789), Dioscorea glauca Muhl. ex L.C.Beck (1833)(pro syn.), Dioscorea hexaphylla Raf. (1837), Dioscorea hirticaulis Bartlett (1910), Dioscorea lloydiana E.H.L.Krause (1914), Dioscorea longifolia Raf. (1837), Dioscorea megaptera Raf. (1837), Dioscorea paniculata Michx. (1803), Dioscorea paniculata var. glabrifolia Bartlett (1910), Dioscorea pruinosa Kunth (1850), Dioscorea quaternata Walter (1788), Dioscorea quaternata var. glauca (Muhl. ex L.C.Beck) Fernald (1937), Dioscorea quinata Walter (1788), Dioscorea repanda Raf. (1837)(nom. illeg.), Dioscorea sativa L. (1753)(nom. cons.), Dioscorea villosa var. glabra J.Lloyd ex A.Gray (1908), Dioscorea villosa var. glabrifolia (Bartlett) S.F.Blake (1918), Dioscorea villosa subsp. glabrifolia (Bartlett) W.Stone (1912), Dioscorea villosa f. glabrifolia (Bartlett) Fernald (1937), Dioscorea villosa subsp. glauca (Muhl. ex L.C.Beck) R.Knuth (1924), Dioscorea villosa var. hirticaulis (Bartlett) H.E.Ahles (1964), Dioscorea villosa subsp. hirticaulis (Bartlett) R.Knuth (1924), Dioscorea villosa var. laeviuscula Alph.Wood (1847), Dioscorea villosa subsp. paniculata (Michx.) R.Knuth (1924), Dioscorea villosa subsp. quaternata (Walter) R.Knuth (1924), Dioscorea waltheri Desf. (1815), Merione villosa (L.) Salisb. (1866)

Dioscorea villosa L. is the accepted scientific name for this species. The genus and species were named and described as such by Carl von Linnaeus in the second volume of the first edition of Species Plantarum in 1753. 

As of 12-16-23 when this page was last updated, Plants of the World Online lists 633 species in the Dioscorea genus. It is a member of the plant family Dioscoreaceae with 4 genera. Those numbers could change as updates are made on POWO.

The above distribution map for Dioscorea villlosa is from Plants of the World Online. Areas in green are where the species is native and purple is where it has been introduced. The map on the USDA Plants Database for North America is the same. The species could have a broader range than the maps show. 

The map on iNaturalist shows where members have made observations. Anyone can join and it is a great website to confirm and share your observations. The maps on iNaturalist are continually updated as members post new observations.

THERE ARE SEVERAL LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING AND TO HELP WITH A BETTER POSITIVE ID.

I found several colonies of Dioscorea villosa growing in the woods on a friend’s farm on May 3 in 2020. Their preference is light to part shade in moist woodlands and along streams, ponds, and marshes although they can grow in drier areas as well.  Multiple stems emerge from a single rhizome producing a whorl of leaves. Stems ultimately grow from 7-15 or more feet tall depending on available light.

Common names include Wild Yam or Colic Root, but the rhizomes are not edible…

As I mentioned, the leaves initially grow in a whorl (usually). At that stage, they can be confused with Smilax lasioneura, which I did… In fact, I had all the photos on this page labeled Smilax lasioneura until I went back and saw they were vining… The plants with leaves growing in more of a whorl were, in fact, the Smilax but it was growing in the woods across the highway with no Dioscorea anywhere near. Then I couldn’t find it again… GEEZ!

Dioscorea villosa leaves are kind of heart-shaped (cordate) with heavy veins. While the lower leaves grow in whorls, they grow alternately on the rest of the vine and are spaced fairly far apart. The upper surface is hairless (glabrous) while the undersides can be either glabrous or have tiny hairs (pubescent). The leaves have petioles (leaf stems) up to 6″ in length.

The vines can grow to 3′ tall before they need support. The stems are glabrous and are usually round but some may have ridges, as in the above photo. Stems and petioles can be green, yellow, reddish-green, or even dark red.

Also in the above photo, I believe is the beginning of a pair of inflorescences growing from the leaf axils. Vines either produce all male flowers or all female flowers which are COMPLETELY different. I will wait until I get photos of flowers to write their descriptions. I also need photos of their fruit… Several websites at the bottom of the page have great photos and descriptions.

I wasn’t able to get back to these woods later in 2020 to get photos of their flowers, fruit, or seeds. Someday, I will go back to get more photos.

I have enjoyed photographing and learning about the many wildflowers growing on the family farm and in other areas. The farm is in Windsor, Missouri in Pettis County (Henry County is across the street, and Benton and Johnson aren’t far away). I have grown over 500 different plants and identified over 250 species of wildflowers (most have pages listed on the right side of the page). I am not an expert, botanist, or horticulturalist. I just like growing, photographing, and writing about my experience. I rely on several websites for ID and a few horticulturalists I contact if I cannot figure them out. Wildflowers can be somewhat variable from location to location, so sometimes it gets a bit confusing. If you see I have made an error, please let me know so I can correct what I have written.

I hope you found this page useful and be sure to check the links below for more information. They were written by experts and provide much more information. Some sites may not be up-to-date but they are always a work in progress. If you can, I would appreciate it if you would click on the “Like” below and leave a comment. It helps us bloggers stay motivated. You can also send an email to me at thebelmontrooster@yahoo.com. I would enjoy hearing from you especially if you notice something is a bit whacky.

FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS/SPECIES)
INTERNATIONAL PLANT NAMES INDEX (GENUS/SPECIES)
TROPICOS (GENUS/SPECIES)
FLORA OF MISSOURI (GENUS/SPECIES)
WORLD FLORA ONLINE (GENUS/SPECIES)
WIKIPEDIA (GENUS/SPECIES)
USDA PLANTS DATABASE
DAVE’S GARDEN
MISSOURI PLANTS
MSU-MIDWEST WEEDS AND WILDFLOWERS
(Dioscorea oppositifolia)
iNATURALIST
WILDFLOWER SEARCH
ARKANSAS NATIVE PLANT SOCIETY
ILLINOIS WILDFLOWERS
MINNESOTA WILDFLOWERS
KANSAS WILDFLOWERS AND GRASSES
PFAF(PLANTS FOR A FUTURE)
GO BOTANY
LADY BIRD JOHNSON WILDFLOWER CENTER
FRIENDS OF THE WILDFLOWER GARDEN
FLORA OF NORTH AMERICA
BACKYARD NATURE
NORTH CAROLINA STATE UNIVERSITY
CLIMBERS (UNIVERSITY OF MICHIGAN)
U.S. WILDFLOWERS

NOTE: The data (figures, maps, accepted names, etc.) may not match on these websites. It depends on when and how they make updates and when their sources make updates. Some websites have hundreds and even many thousands of species to keep up with. Accepted scientific names change periodically and it can be hard to keep with as well. Some of the links may use a name that is a synonym on other sites. In my opinion, Plants of the World Online by Kew is one of the most reliable and up-to-date plant databases and they make updates regularly. I make updates “at least” once a year and when I write new pages or add new photos but I do get behind. We are all a work in progress. 🙂