who is on first? Confusion?

 The article's title promised to tell you how to grow potatoes.  Here's the photo they used to illustrate the article which compounded the confusion. OK all you sharp eyed plant people see the confusion right away because this is obviously a sweet potato, not a potato.  This is mostly a storage root but it is a stem at one end (as is obvious).  This is Ipomea batatas, a morning glory, and note the specific epithet, which sounds as if a young kid was saying "potatoes", a common name that got transferred to storage stem (a tuber) in the nightshade family Solanum tuberosum.  Both from Peru.  The common name got switched leading to much confusion.  And don't even think about bringing up the name yam.  The article was about the latter and did not mention sweet potatoes.  

Is a white potoato a vegetable?

Perhaps spurred by potential squabbles over school lunch nurtitional guidelines, TPP has been asked this simple question. The simple answer is, yes, the white potato is a

vegetable, which by definition is an edible root, stem, or leaf. The white potato (although they also come in pink, yellow, and blue skins & flesh) is a tuber, a modified stem. However this vegetable is in a special category that we call starchy staples. These are basically vegetables that supply a significant amount of dietary calories. So the white potato is heavy on calories (although low fat). When thinking in terms of balanced diets, the white potato is more like rice and bread than like kale or carrot. Tater tots are not even remotely like eating carrot sticks.

Genomic studies confirm the tomato is a fruit. Duh!

Really?  Genomics confirms that the tomato is a fruit, not a vegetable?  No, probably just Gisela's lame attempt at humor.  There are a lot of good reasons for genomic research, comparing one genome to another, but it doesn't seem that this science writer touched on any of them. Genomic research wasn't needed to identify the domestic tomato's closest wild ancestor; yes, it confirmed it, but it was already known, well known.  And yes, tomato is pretty close to potato too, but that was already so well known that tomato has been transferred back into the genus Solanum, discarding its colorful genus Lycopersicon ("edible wolf peach", maybe distinguishing it from other toxic red-fruited nightshades), a triumph for Linnaeus who put it there in the first place.  So what did we learn from this fluffy bit of science news?  Not much.  

Yams are not sweet potatoes and vice versa!

There in the 1st chapter of this book on plants is the phrase, “consider sweet potatoes in the genus Dioscorea” (Food of the Gods by T. McKenna), but considering the pseudoscientific approach this author takes such errors are not unexpected (must be his non-rational reality – seriously). So the Phytophactor shall endeavor to straighten this out.
Sweet potatoes are not yams; Dioscorea is the genus of yams, one of which is pictured here. Sweet potatoes are Ipomea batatas in the morning glory family (dicots). Yams are monocots. Sweet potatoes are storage roots (although at the root-stem junction) and yams are modified stems (tubers). See the nodes (“eyes”)? What you get in North American markets are sweet potatoes, and yes, the larger, fleshier varieties are called “yams” but they aren’t yams. And those “candied” yams in cans are sweet potatoes too.

The discerning among you will have noticed that the native name for sweet potatoes "batatas" was preserved in the scientific name, and you guessed it, this common name was misapplied by Europeans to another plant native to the same region (Peruvian South America) Solanum tuberosa, the "potato", which is not Irish in the least.