Winter is the season for citrus fruit, and January is the month for breaking out of old routines, so stop staring at your navel and learn about one of the weirder citrus varieties.
I’ll never forget the day one of my general botany students brought to class a Buddha’s hand citron, pulled from a tree right outside our classroom. I had only recently moved to northern California from Indiana, and I’d never seen anything like it: it was a monstrous mass of a dozen pointed twisted fingers splayed irregularly from a stout base. It had the firm heft and girth of a grapefruit and the unmistakable pebbled skin of a citrus fruit, so I wondered whether my student had found a grossly deformed grapefruit; but the oil in the peel smelled heavenly and not at all like a grapefruit. In class we cut through a big finger and found no juicy segments, just white citrus pith all the way through.
Immature Buddha’s hand on the tree
We eventually discovered that this fascinating fruit was a Buddha’s hand citron, Citrus medica variety sarcodactylis, meaning fleshy (sarco-) fingered (-dactyl) citron. Since that day many years ago I’ve become an unapologetic (if surreptitious) collector of the fruits from that same campus tree. The citrons do not drop from the tree on their own, yet I often find one or two lying nearby, probably torn off by a curious tourist or student and then abandoned. Obviously these fruits need a good home, and where better than the window sill in my office?
The first time I left one closed up in my office over a weekend, I opened the door on Monday morning to a waft of fruity floral aroma. It turns out that many people in China and India use the fruit to scent the air, although in west Asia and Europe the fleshy fingers are more often candied or used to flavor alcohol. I do both: the fruits make my office smell nice until they are fully yellow, and then I cook them.
It can be difficult or expensive to get your own hands on a fingered citron, but it’s easy to find a navel orange almost any time of the year. Fortunately, the patterns underlying the morphology of the fingered fruit can also be seen in an everyday navel orange. Between our photos of Buddha’s hands and your own navel orange, you should be able to follow along at home. Continue reading
Biologist Jessica Savage answers a few of our questions about her research on the physiology behind giant pumpkin size.
In October 2014, a giant pumpkin grown by Beni Meier of Switzerland tipped the scales at 1056 kilograms (2323 pounds) and set a new world record for the heaviest pumpkin ever weighed. Modern competitive pumpkin growers have been imposing very strong selection on pumpkin size for decades. Pumpkin fruit size keeps climbing, and old records are broken every year or two (Savage et al. 2015).
Beni Meier with his 2014 record-winning 2323-pound pumpkin, presumably a specimen of the Atlantic Giant variety of Cucurbita maxima. Photo from here.
Posted in Education, Fruit, The basics
Tagged anatomy, Atlantic giant, Cucurbita, Cucurbita maxima, Cucurbitaceae, evolution, fruit size, giant pumpkin, hubbard, interview, Jeanne L. D. Osnas, Jessica Savage, phloem, physiology, pumpkin, xylem
Will seedless watermelons make us superhuman or turn our children into giants? Hardly, but they do give home cooks the power to count chromosomes without a microscope. Just a knife or a hard thunk on the sidewalk are enough to get a watermelon to spill its genetic guts.
If you were reading a Hearst Corporation newspaper in late 1937, you might have thought humanity would eventually be swallowed up by giant carnivorous plants, unwittingly unleashed by uncontrolled biotechnology. The San Francisco Examiner reported on November 21st of that year that the discovery of an “elixir of growth,” meant that “…science may at last have a grip on the steering wheel of evolution, and be able to produce at will almost any kind of species…” including “…a plague of man-eating ones.” In 1937 Americans had much more important things to worry about, just as we do now. Still, that discovery may in fact have threatened one cherished aspect of the American way of life by triggering the slow demise of late summer state fair watermelon seed spitting contests. It doubtlessly paved the way for seedless watermelons, and in 2014 the total harvest of seedless watermelons on American farms – nearly 700 thousand tons – outweighed the seeded watermelon harvest more than 13 to 1 (USDA National Watermelon Report). A similar pattern is emerging this year. Is there no stopping the attack of the seedless watermelons?
CLICK to read. Image from microfilm of an actual page in the San Francisco Examiner, published Sunday November 21, 1937. Found in the Media and Microtext Center of Stanford University Libraries.
And more important, how is it even possible to get seedless fruit from an annual plant? From a plant whose only mode of reproduction is through those very seeds? From a plant that cannot make suckers as bananas do and cannot be perpetuated endlessly through grafts like fruit trees and vines? Such is the challenge posed every single year by watermelons, but thanks to the “elixir of growth” discovered by Albert Blakeslee and subsequent work by Hitoshi Kihara, one of the most prominent agricultural geneticists of the 20th century, the world has an elegant solution. Breeders continually improve the varieties available, and consumer demand keeps growing, yet seedless watermelon production methods have remained essentially unchanged for three quarters of a century. Continue reading
What’s in a name? An apple with an old fashioned name could taste as sweet, but it might not sell. The most sought after branded varieties reveal what people look for in an apple: sweet and crunchy and bright white inside. Do the fruits live up to their names? Are Honeycrisp apples crunchier than others? Do Arctics actually stay white? We zoom in on the cells to find out.
Some of you will remember the era when the Superbowl halftime show repeatedly featured Up With People. That was around the time when Granny Smiths arrived in our supermarkets and finally gave Americans a third apple, a tart and crunchy alternative to red and golden delicious. Those were simple days. Continue reading
Infinity scarves? No. They won’t keep doctors away. Apples are the ultimate everyday accessory (fruit). Katherine explains where the star in the apple comes from. Could it be due to a random doubling of chromosomes? We also give readers the chance to test their apple knowledge with a video quiz.
Although apples are not particularly American – nor is apple pie – they color our landscape from New York City to Washington State, all thanks to Johnny Appleseed. Or so goes the legend. Everyone already knows a lot about apples, and for those wanting more, there are many engaging and beautifully written stories of their cultural history, diversity, and uses. See the reference list below for some good ones. There is no way I could cover the same ground, so instead I’ll keep this post short and sweet (or crisp and tart) by focusing on apple fruit structure and some interesting new studies that shed light on it.
Of course if you do want to learn more about apple history but have only 5 minutes, or if you want to test your current knowledge, take our video quiz! It’s at the bottom of this page. Continue reading
Walnuts may not seem like summer fruits, but they are – as long as you have the right recipe. Katherine takes you to the heart of French walnut country for green walnut season.
Public domain, via wikimedia commons
English walnuts do not come from England. The English walnut came to American shores from England, but the English got them from the French. The (now) French adopted walnut cultivation from the Romans two millennia ago, back when they were still citizens of Gallia Aquitania. Some people call this common walnut species “Persian walnut,” a slightly better name, as it does seem to have evolved originally somewhere east of the Mediterranean. But the most accurate name for the common walnut is Juglans regia
, which means something like “Jove’s kingly nuts.” I think of them as queenly
nuts, in honor of Eleanor of Aquitaine, because if any queen had nuts, she certainly did. During her lifetime the Aquitaine region of France became a major exporter of walnuts and walnut oil to northern Europe, and it remains so more than 800 years later. Continue reading
What can make me feel less guilty about buying bananas? Science.
Trying to get the banana back in the peel
I am genuinely curious about the size of the fraction of carbon in my two-year-old that is derived from bananas. When we have bananas in the house, which is most of the time, she eats at least part of one every day. She loves them peeled, in smoothies, dried, in banana bread, or in these banana-rich cookies, which sound like they shouldn’t be good but are totally amazing. Bananas are inexpensive and delicious, and making nutritious food with them gives me a sense of parental accomplishment. Nonetheless, always I feel a niggling sense of guilt whenever I plunk a bunch of bananas into the shopping cart. Prosaic though it may be, most of this is contrition inspired by the “local food” movement. I know that very little is benign about the process responsible for bringing these highly perishable tropical fruits to my table for less than a dollar a pound. The remainder of my remorse is conviction that bananas should not be taken for granted. Not only is banana history and biology interesting, but the banana variety in our grocery stores, the Cavendish, is in danger of commercial extinction. There isn’t an easy solution to the problem or an obvious candidate for a replacement variety. The history of the Cavendish’s rise, and the biology behind its current peril, makes for a good story. Continue reading
Flavorful and juicy thought it may be, Thanksgiving turkey, for me, is merely the vehicle for the real star of the meal: cranberry sauce. And cranberry is in the same genus as blueberries, lingonberries, huckleberries, and billberries. And they all make their own pectin. Let us give thanks this holiday season for Vaccinium.
Cranberry sauce is my favorite staple item at our big holiday dinners. Long-prized by indigenous North Americans, cranberries would have been in the diet of those Native Americans participating in the first Thanksgiving if not part of the meal itself. When the fresh cranberries hit the stores in late fall, we stock up. Cranberries, however, are not the only member of their genus that is perennially in our freezers or in our annual diet: blueberries, many huckleberries, lingonberries, and billberries are all in the large genus Vaccinium (family Ericaceae, order Ericales). Continue reading
Posted in Fruit, Uncategorized
Tagged billberry, blueberry, cranberry, Ericaceae, fruit, huckleberry, Jeanne L. D. Osnas, lingonberry, pectin, phylogeny, Vaccinium
What is a nut, and why is the answer so convoluted? For Thanksgiving, Katherine explores pecans and the very best vegetarian turkey substitute ever: pecan pie.
Thanksgiving is all about tradition, and wherever there is tradition, there are entrenched ideas about the right way to do things. Strong opinions can breed discord, judgmental grumbling, or silent rants about how people with so little sense cannot possibly be blood kin or their freely chosen companions. So much for the theory of mind we all developed as toddlers. And so it goes with my feelings about pecan pie.
Pecan pie is properly made according to the recipe on the Karo syrup bottle, preferably by my own father. The recipe does not include bourbon. To be clear, I love bourbon. Bourbon is our only indigenous whiskey. It is made of corn and aged in American oak. I love bourbon, and I respect it enough to drink it neat, from a glass, alongside my pie.
We can all agree that pecan pie should not be rolled in molasses, breaded with crushed pork rinds, and deep fried. Some reasonable people, however, do add chocolate. It might taste just fine that way – even delicious – but it disqualifies the resulting pie from the category under discussion. Sneaking it in under another name doesn’t work either. When the good bourbon-loving people of Kentucky add chocolate to a pecan pie and call it Derby pie, not only are they infringing on a trademark, they are using the wrong kind of nut. Derby-Pie ® is made with walnuts. There is therefore still no excuse for adulterating good pecan pie with chocolate.
What is a pecan?
A pecan half is a rich fat-filled embryonic leaf (a cotyledon) from a pecan tree seed. The flat side of a pecan half bears a pale shield-shaped scar where it was joined to the other cotyledon and where a tiny knobby embryonic root sits waiting for the chance to grow out and start drawing up water. Each pecan half is wrinkled like a brain hemisphere, crammed into its shell. In the natural world, when conditions are right for germination, a pecan seed imbibes water and its cotyledons swell enough to crack open the shell. The cotyledons provide an extremely calorie-dense sack lunch for the seedling to draw upon until it develops leaves and starts photosynthesizing food on its own. Continue reading
A shorter version of this essay appears in the Autumn 2013 issue of the beautiful, creative online magazine Soiled and Seeded. Here Katherine and Jeanne explain the topological relationship between figs and mulberries and do a little investigative journalism.
Figs and mulberries are both gorgeous, sexy fruits, but in very different ways. At first blush a mulberry could be the fragile hot-mess cousin of a blackberry, while figs are classically sensual fruits, like marble nudes teetering on the edge of vulgar. For all their fleshy assertiveness, both fruits keep their secrets; and it takes more than a long, intense gaze to uncover their close relationship and know what makes them sweet. Mulberries may look like blackberries (and share a taxonomic order), but they are built from different plant components. The true siblings are mulberries and figs (both in family Moraceae), and at heart they are very much alike, although figs are clearly the more introverted of the two. Continue reading