The Potato that Circumnavigated the Globe

An oldie but a goodie — from November 2019…

A potato, a yam, and a sweet potato were sitting in a bar. The sweet potato said, I think I’ve had a few too many… better call me a Tuber….

Fozzie Bear: What is the potato’s least favorite day of the week? Fry-Day! I’ll be here all week. Photo from Pinterest.

Did you know that yams and sweet potatoes are not the same–oh you did? Did you know that potatoes and sweet potatoes are not the same species–oh you did? Ok, did you know that sweet potatoes sailed to Polynesia? Gotcha there.

Also, potatoes once made Queen Elizabeth ill. Yams, which are more clever, once ruled the world. And, since those bastard potato plants pretty much destroyed an entire country and created a big chunk of a new one, that makes the lowly potato pretty down powerful. Yep, I started poking around to find out why potatoes and sweet potatoes aren’t related and I found all sorts of interesting stuff. We’re goin’ in!

One Potato, Two Potato

The Spanish coined the word patata from the Taino (West Indian/Caribbean) word batata as well as after the Quechuan (Inca/Peru) word papa. Aside from the fact that potatoes don’t come from Spain and that West Indians were on an entirely different side of the planet from India, let’s unpack this etymological fact. The Spanish, courtesy of the Italian Christopher Columbus, were wandering all over the mid-section of the New World after their ships ran into the Caribbean during the 16th century. They were all over the Caribbean and South America, not to mention the dangly bits of Florida and Baja California.

Both the Taino cultures and Quechuan cultures encountered by those Spanish relied heavily on root vegetables. The Taino called theirs batatas, so when the Spanish traveled further west and found a similar-looking blob, they decided it was the same type of plant. Besides, they couldn’t use the local Quechuan word papa because the Pope was already using that term. Both vegetables were referred to as patata, or sweet potato, even though potatoes and sweet potatoes are, botanically, not related (more on that shortly).

A 16th century botanist named John Gerard called the true sweet potatoes common potatoes, which is especially confusing today when our non-sweet potatoes are far more common. He also called those Quechaun Peruvian non-sweet potatoes bastard potatoes or Virginia potatoes, which is especially curious because potatoes don’t come from Virginia at all. Sometimes we call those non-sweet potatoes white potatoes, but since so many of them are red, gold, and purple, that makes even less sense. I like the term bastard potatoes because these bastards naming these potatoes created no end of confusion.

Patatas, which are not sweet potatoes. Photo from Wikipedia.

The plot thickens, or perhaps I should say mashes. Sweet potatoes in most U.S. stores are often labelled as yams even though they are absolutely not yams. The original sweet potatoes, which did genetically spring forth from the Caribbean, were white-fleshed. An orange variation was developed through cross-breeding, and for marketing purposes in stores was called a yam, from the Portugese inhame and Jamaican word nyaams meaning to taste. Those varieties, like the Garnet, were then called yams, not to be confused with the yams that came from Africa.

Not yams. Photo from

1st botanist: Are you sure you want me to call these yams and not sweet potatoes?
2nd botanist: Didn’t you hear me? Did I spudder?

Are We Related to Gorillas?

Internet research has told me, repeatedly, that potatoes, sweet potatoes, and yams are not related. To some degree, this is like pointing at your drunk cousin and saying, “I’m not related to that guy.” They are all plants, after all. Also, the three plants are all tubers. Tuber means that the growth or thickening of the plant is a place for storing nutrients and energy so that the plant can regrow next season. However, if I follow the bouncing botanist, saying that all tubers are related would be like saying a lizard is like an antelope because they both have four legs. Other than that, they’re not related.

This one is an actual yam. Photo from wikipedia.

Yams are monocots, a type of angiosperm… oh, gosh, these terms! Ok. Angiosperm is a flowering plant and a monocot means it has one embryonic leaf in the seed embryo, whereas a dicot would have two. Sweet potatoes are dicot, meaning they have two. I don’t really understand what that means, but I found a chart, and I can read a chart! All three edibles are flowering plants (angiosperms) but yams split off very early in the family tree. In this clade chart, yams are the red stripe on the right, while sweet potatoes (and bastard potatoes) are the tiny red line on the left.

Photo from Botanist in the Kitchen

Potatoes and sweet potatoes, which both originated in the Americas, are on the same branch of this tree, both in the Order Solanales. (I remember the taxonomy from 7th grade: Kingdom, Phylum, Class, Order, Family, Genus, Species. They call them clades now, but think Class-Mammals, Order-Primates, Family-Man etc.) If they’re both in the Order Solanales that means both potato-types are related in the same way that humans are related to gorillas. Distantly related. Even if your drunk cousin looks like a gorilla.

Yams are in an entirely different Class (Liliopsida-monocot) from the other two which are Mangoliopsida-dicot. Curiously enough, one of the other famous Family Solanales is the tomato, which doesn’t look like a potato at all, although both tomatoes and potatoes originated in western South America. Solanales are all in the nightshade Family grouping, which means you better treat them right or they’ll slip their poisonous leaves into your tea.

Three angiosperms walk into a bar. The bartender says, “You guys are early, how’d you get here so fast?” and one replied, “We took the carpel lane.”

Famous botanist joke that I just made up
The Free-Thinking Nature of Yams. Photo from

Tubers, Grab Your Passports!

The other thing that differentiates yams is that they are considered to be cosmopolitan, which according to Merriam-Webster, means they have a skyline, are free from national prejudices, and enjoy a cocktail or two. That’s right. Yams–and I do mean the ones that started in Africa, not the West Indies (which are not near India, remember!)–yams are swingers! By the way, if you try to look up yams and cosmopolitan, you get twelve recipes for things that are NOT YAMS, and one article in Cosmopolitan about how Idris Elba wants you to pound his yams, which is a bit cheeky. But at least Idris is talking about actual Yams.

What did the African tuber say to Popeye? I Yam What I Yam. Photo from

Because the true yams, the monocots, the stem tubers, the ones that are like grasses and not like tomatoes, were born in Africa. Yams can trace their ancestry back to the West Niger River Basin, 10,000 years ago. You can tell by looking at these yamma-jammas that a single one could probably feed a family of six. You could also see from that map above that yams propagated more widely than their potatoey distant cousins, since there are now native species of yams across most of the world. That’s what makes them true cosmopolitan.

Erin Go Bragh Us Potatoes!

Potatoes, of course, did not come from Ireland, though many of us did learn in school about the significance of the Irish potato famine and its influence on immigration. Geneticists linked to the International Potato Center in Peru have mapped the potato genome and determined that 99% of all existing potatoes originated in the lowlands of southern Chile, then migrated to Peru, where the Spanish found them. There are now hundreds of varieties, including an Andean potato adapted to the short daylight hours near the equator and a Chiloe Archipelago potato that has adapted to the long daylight conditions below the Tropic of Capricorn.

The Spanish brought the potatoes back to Europe, noting by the way that they helped prevent scurvy in the sailors, proving that potatoes are high in vitamin C. One legend says that the Spanish Armada carried the potatoes to Ireland when they were fighting the British, ending up in Irish waters when the Spanish ships were lost at sea. However, it is known that Sir Walter Raleigh bought the potato to Ireland from Spain and Italy. Another story says that he offered the potato to the Elizabethan court and they decided to celebrate the potato in a big feast. The cooks became a little confused, however, and they threw out the lumpy dirty blobs at the bottom, instead serving the leaves like salad. Those nightshade leaves. Didn’t go well.

Officially, the potato was first cultivated in America in 1719 in Londonderry, New Hampshire by Scotch-Irish, meaning that Irish immigrants did in fact give them a foothold in the U.S. They were also propagating widely in Ireland because they do grow easily compared to some other plants. But a potato blight wiped out the crops in the mid 1840s and sent the Irish fleeing by the hundreds to America. Today, the Irish-American number around 30 million in the U.S., almost 10% of our population, compared with only about 6.5 million in Ireland itself. That’s no small potatoes.

What do you get when you cross a potato and a sponge?
I don’t know, but it soaks up a lot of gravy!

Victor Borge

The Sweet Potato Learns the Hula

So yams started in Africa and spread their free love and socialism everywhere, while potatoes originated in the Andes but instead of traveling straight north up to Idaho had to detour through Spain and then Ireland. What about our third tuber–the one Americans love to serve on Thanksgiving–the sweet potato?

Sweet potatoes came out of the tropics, out of the Yucatan, the Caribbean, and the mouth of the Orinoco river in Venezuela. They were cultivated by the natives at least 5,000 years ago, but then the story gets even more interesting. The sweet potato ended up in the Cook Islands, Japan, and the Philippines. Archaeologists have found remains that they can carbon date back to between 1000-1100 AD, definitely predating the Spanish and European sailors.

The travels of the sweet potato as evidence by language. Diagram by Caroline Roullier from

Linguists had long noticed similarities in the word for the tuber, as cross bred varieties had cropped up around the Pacific Island cultures. Recent analysis of both the genetic origins and the archaeologic evidence suggests that the Polynesians traveled to South America, then took home some sweet potatoes. Not potatoes, though, because it seems as if they couldn’t quite get up into the mountains where those bastard potatoes were growing.

Now, there’s also some evidence that the Polynesians may have brought chickens with them, introducing those non-natives into South American prior to the Europeans. But let’s not fowl up the story with another topic.

Suffice it to say, if you know a biologist or botanist, this is a good week to shake their hand for helping to bring forth all the tubers. When you’re in the middle of peeling your twelfth Russet potato or digging around for the marshmallows or maple syrup to dump on your Ipomoea batatas, consider the long journey that either of them made just to end up on your Thanksgiving plate. Give a little thanks to the International Potato Center and to the llamas that must have carried those potatoes down the Andes. Just don’t call them yams.

Say what? did she say yams a-gain? Photo from the The Llama Park.

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