Yam is the common name for two plant species.
One belongs to the genus Dioscorea. Dioscoreaceae produce edible tubers.
These yams are native to Africa and Asia.
Dioscoreaceae vary in size and medicinal activity.
Wild Mexican yam is used by many women for its hormonal activity and effects on menopause.
Dioscorea tubers, taken as a dietary supplement, are thought to promote human health by improving hormonal and immune-type response.
It is also theorized that extracts of various species of dioscoreace, taken together, fight cancer.
The other plant known as yam is the sweet potato (Ipomoea batatas).
These yams are not members of the family Dioscoreaceae, which true yams belong.
Instead, sweet potato yams belong to the Morning glory or Convolvulaceae family.
Thanksgiving is a time of sweet potatoes.
Botanicaly, both groups are angiosperms or flowering plants.
Dioscoreacea are monocots, meaning they originate from a single leaf while Convolvulaceae are dicots and develop from two.