Edition 2: Citrus 101

Edition 2: Citrus 101

What's up with citrus?

Oct 22, 2021

While boppin’ around Barbados doing colonial stuff back in 1750, the Reverend Griffith Hughes made a fascinating discovery: the original forbidden fruit from the Garden of Eden.  Aha, he cried, this is what must have tempted God’s most perfect creation to cast themselves and their progeny into eternal suffering.

What was this fruit Rev. Hughes discovered?  A fruit so succulent, decadent, and capable of conferring the knowledge of good and evil that it caused the fall of mankind?  It was a grapefruit, of course.  More precisely, it appears to have been a whole panoply of various grapefruit-esque citroids, most of which the exact identity has been lost to time and memory.

We’re not ecclesiastical enough to argue with Rev. Hughes’ contention that Adam & Eve were Barbadians, but sure, we’ll go with it.  So will Science, apparently, which has consecrated the grapefruit with the taxonomic name Citrus paradisi.

Now, Citrus might conjure some kind of neat, orderly image in your mind: lemons, limes, oranges and grapefruits lined up on a grocery store shelf.  But do not believe the smiling grocer: in reality, citrus is a seething, shimmering, shapeshifting orgy of hybrids, rootstocks, cultivars, wildtypes and forbidden fruits lost to time and memory.  More Garden of Earthly Delights, less Paradiso.

If you ever find yourself googling one of these grocery store citroids, you’ll quickly discover that every citrus fruit is a hybrid of multiple other kinds of citrus fruits, and you’ll tumble down a rabbit hole into a genetic lineage twisted around itself like a sour, sticky ouroboros. Welcome.

Science recognizes five ancestral citrus species, the pantheon from which all others have sprung: the Citron, the Pomelo, the Mandarin, the Small-flowered papeda, and… the Kumquat, which slid into Papeda’s DMs to bring forth something called a Limequat. The Habsburgs could never. 


But for a long time, actually, there was only one ur-citrus species, Citrus linczangensis, living deep in the Himalayas like small hard bitter monks.  Then, four million years ago in the Pliocene, the Five Citrus Ancestors appear to have sprung into existence out of whole cloth during some kind of “speciation event”, and ever since then it’s been total primordial chaos in the citrus realms, with every species so primed to hybridize that even a dusting of some strange pollen will coax a lime tree to produce a grapefruit.  Feast your eyes on Wikipedia’s list of citrus fruits, the Bergamots, Lumias, Calamondins, Oroblancos...

Reverend Hughes was definitely picking up on something biblical about citrus: Mandarin begat sour orange begat lemon begat mexican lime begat limequat...

If you take a Mandarin and a Pomelo, you get an orange.  If you take an orange and a citron, you get a lemon.  If you take an orange and a pomelo you get a grapefruit, and if you add another orange you get a tangelo.  Citron + Orange = Meyer Lemon.  If you take a Kumquat and anything else, you get to just add -quat to the name of the new fruit: Orangequat, Yuzuquat, Procimequat (which is what happens when you mix a Limequat with an OG Kumquat again).  

And let’s not forget about the Citrange, which is a cross between a sweet orange and a trifoliate orange, and when you mix that with a Kumquat you get a, you guessed it, Citrangequat.  The Quats were actually considered to be their own genus, Citrofortunella, until recently, when it was determined that they’re actually all Citrus through and through.

If all of this seems a bit tawdry and profane, you’re not alone. 

“There’s something fascinating, freaky, even sexy about citrus,” says pomologist David Karp.

We’ll say. Although you probably don’t get into pomology without feeling some type of way about pericarps. 

We can’t decide if Citrus breeds need an annual presentation where they can parade around in their own Westminster-style Fruit Show, or some After Dark cable series devoted to the more illicit web of citroid liaisons. (🤫). Maybe both.  

Citrology is, naturally, a riveting and highly controversial field.  Every pomologist who wades into the citrus fray gets to watch as their carefully curated and distinct taxonomies eventually get discarded and dissolved back into the citroid genetic soup.

Even the grandaddy of all citrologists, Walter T. Swingle, whose bibliography includes “The grain smuts: how they are caused and how to prevent them” and “Citrus ichangensis, a promising, hardy, new species from southwestern China and Assam”, and who devoted his life to discovering citrus species and classifying them, had his entire life’s work undone when most of the “new” genera he discovered were revealed through genetic analysis to still be Citrus.

Even our trusted Citrus paradisi was eventually renamed Citrus X paradisi to denote its wild, hybridicalized nature.  (The X paradisi Files? 👽)

Suffice it to say, there is nothing true one can say about citrus that will stand the test of time.  In fact, remember up there where we said there were five OG citroids?  That is the most commonly cited pantheon, but in 2018 a study suggested that there are actually 10 OG citroids, including three weird little limes which come from Australia.  

The most interesting of these three is the Finger Lime, whose peel is a scandalous vermillion and which is packed full of “globular juice vesicles” that the LA Times tried to convince us were the “caviar of citrus.”  Not content with their OGs (original globuals), Australians have gone on to cross a Finger Lime with a Calamansi, producing the “Australian Sunrise” lime.  We await the Forbes article “Australian Sunrise: the Tesla of Globular Vesicles.”

Fascinatingly, there is one of Swingle’s genera, Poncirus, which contains fruits like the aforementioned trifoliate orange, that is scintillatingly close to collapsing back into the Citrus genus, but that has thus far proven itself genetically distinct juuust enough to avoid that fate.  For now.

However, we predict, eventually Science will discover that every living organism is actually some kind of citrus hybrid. Is it a coincidence that the citric acid cycle is the foundation of all cellular life?  We think not. (Editor’s note: all of our products are free of added citric acid. No artificial chemical taste here.) Consider once more Reverend Hughes’ conception of Eden as a beach on a small island in the Caribbean, where the Holy Spirit putters around, lovingly tending to a wild orgy of multitudinous citrus from whence all life flows forth.  

We ask: where’s the lie?

- By our friends at The Bubbleverse

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