Cinnamon Vine: A Cold-Hardy Yam that Grows Aerial "Potatoes."
There is a plant on this Earth that grows little potatoes above ground. Let that sink in... little potatoes.
Okay, this same plant that grows little above-ground potatoes also grows a giant edible yam below ground. Weirder... loving it, right?
This colossal yam that grows little potatoes like fruit can ALSO be grown in temperate North America. Okay... keep calm.
This yam that grows tiny potatoes and can survive the winters of North America is not only ornamental, but it smells strongly of cinnamon when in bloom.
*The narrator allows you time to change your botanical pants.
Dioscorea polystachya was a major contender to overtake the potato as the World Tuber Champion for a hot moment, and then, like a wisp of smoke from an extinguished candle, the Cinnamon Vine simply went away. Of course, there is always more to the story.
Welcome to the almost unbelievable world of Dioscorea polystachya.
This plant is grown in gardens under a variety of conditions, but has escaped cultivation and has largely invasive on the eastern half of the United States especially in moist/disturbed areas .
How to Grow
A study appearing in the Annals of Botany concluded that the bulbils more effectively produced new plants after several months of cold stratification (planted in October) . Dioscorea polystachya can be grown by planting the bulbils, portions of the root, or cuttings. The latter option is said to yield the smallest tubers at harvest time.
Dioscorea polystachya presents aerial tubers that can be eaten raw or cooked and yam below ground that can be prepared in the same manner . The root tubers can be dried and ground into flour for breads and puddings .
In CHINA, the powdered root was used to soothe the skin .
In the early 19th century, due to the historically reclusive nature of the Chinese Empire, the existence of the Cinnamon Vine was thought to be a hoax: a crypto-botanic specimen that existed solely within the mind of a delusional geek somewhere .
"Sure, Rodger, I believe you about your 'potato tree.'"
However, for want of an alternative crop following the horrific Irish potato famine (1845-1849), such rumors were investigated in earnest. Just like that, alternative root-crop speculation became a real thing, and people couldn't believe what they could possibly have on their hands with D. polystachya: an ornamental yam that bears "potatoes" like fruit from its branches AND it could survive the winter .
*Hear the collective gasp of so many 19th century commodities traders.
The search was on.
The Western world discovered that not only was the plant real, but— had they simply noticed things— they would have known that D. polystachya had been a staple food heavily sold in the public bazaars of Singapore for yearrrrrsssss .
Geeks gave way to actual nerds who investigated and delivered actual lectures at actual government institutes and symposiums on D. polystachya . Suddenly, grand prize ribbons were being affixed to 25-inch (64 cm) Chinese yams at fairs in New York City  and people were singing the praises of D. polystachya in the streets. The West could hardly believe that the roots, cut in three pieces and buried in sand, could survive the ten-months-long journey by boat from China to New York City totally alive and ready to plant .
The Chinese Yam was delicious, and seemingly indestructible; speculators were going crazy; surely, Rodger was furious, but then...
The ascent of D. polystachya was as dramatic and sudden as its departure; the Chinese Yam virtually disappeared from the American record and consciousness as a flash of fireworks or a one-hit wonder. WHY? Without a definitive answer, I believe there were a few factors at play.
There are passing references to the relative inconvenience of harvest of the Chinese Yam compared with the potato; apparently the root runs deep and is harder to harvest . Then the potato overcame it's near extinction and re-entered the market.
Finally, the ease with which D. polystachya grows may well have contributed to its fall into obscurity. The plant is now listed as invasive in many parts of America. Why pay for something that offers itself for free? I mean, other than this site. Feel free to send money to this site whenever.
I'll leave you with the words of New York City nursery-man, William R. Prince... a man who fought hard to bring this plant into regular agricultural rotation.
"As a summary of its properties, we have, first—its per-
fect hardihood; second—its agreeable and highly nutritious
quality; third—its easy and cheap culture; fourth—its abund-
ant product; fifth—its capacity of being preserved in a dry
and perfect state, above a year, free from sprouting and decay.
It would be, indeed, a difficult task for the mind of man to con-
ceive and demand a more perfect boon from his Creator."
William R. Prince (1857) 
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 Prince, W. R. (1857). Wm. R. Prince's address to the American Institute: on the character and merits of the Chinese potato-dioscorea batatas, delivered March 17, 1857.
 Jumelle, H. (1910). Les plantes à tubercules alimentaires: des climats tempérés & des pays chauds. Paris: O. Doin.
 Cantley, N. (1886). Notes on economic plants. [Singapore].
 American Institute of the City of New York. (1857). Annual report of the American Institute of the City of New York. Albany, New York, C. van Benthuysen.
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 Jeffrey L. Walck, M. Shea Cofer, Siti N. Hidayati; Understanding the germination of bulbils from an ecological perspective: a case study on Chinese yam (Dioscorea polystachya), Annals of Botany, Volume 106, Issue 6, 1 December 2010, Pages 945–955,
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 (n.d.). Retrieved February 19, 2018, from https://www.invasiveplantatlas.org/subject.html?sub=4527