Air yam foliage in July
James H. Miller, USDA Forest Service, Bugwood.org
Air yam was introduced into the U.S. from Africa during the 1800s as a possible food source and is presently cultivated for medicinal use. As an ornamental, it is often spread by unsuspecting gardeners intrigued by its dangling yams.
Keywords: Dioscoreaceae, perennial, herbaceous, vine, climbing, heart-shaped leaves, rare flowers, monocot, tubers, trellises; Common names: air potato
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Air yam distribution
Air yam is a herbaceous, high climbing vine that can grow to 65 ft. long. Its stem is twining, branching, and hairless. Leaves are alternate, heart-shaped to triangular with elongated tips, thin, hairless, 4 to 8 in. long and 2 to 6 in. wide. They have long petioles, broadly rounded basal lobes, and smooth margins, and are dark green with slightly indented curved veins above (giving a quilted appearance) and lighter green beneath. Rare, small, male and female flowers may appear in panicles or spikes on separate plants between May and August. Flowers are green to white and fragrant. Smooth, spherical aerial tubers (bulbils) up to 5 in. long and resembling miniature potatoes are the most notable fruit, with 1 to 4 occurring at leaf axils. Fruits drop and sprout to form new plants. Air yam also spreads and persists by underground tubers. It grows rapidly on open to semishady sites. Plants die back during winter, but are able to cover small trees in a year, with old vines providing trellises for regrowth.