How Old Is A Ginkgo

Today’s question was raised by my 5-year-old on our walk to school last week. Our walk takes us past a ginkgo tree, and I pointed out the leaves (bright yellow right now, and distinctive no matter what time of year), and busted out the two pieces of ginkgo trivia I remembered: one, the nuts are edible but can be toxic to humans if you eat too many, and two, ginkgos have been around since the time of the dinosaurs.

The goblin immediately decided not to try their luck with the nuts, even if they are considered a delicacy in small quantities. And I was left wondering if my half-remembered fact about ginkgo age is correct. That same day we spotted a woman wearing a ring styled to look like a ginkgo leaf and that brought back the memory of a summer spent in Prague, more than 20 years ago now; I obsessively photographed any ginkgo decoration I found around the city but never looked into why ginkgos were such a popular design motif during the Art Noveau movement. All of which leads me to ask…

How old is the ginkgo?

Old! They’ve been around for about 270 million years (along with trees like the monkey puzzle and the Wollemi pine), which we know because we’ve found fossil leaf impressions and fossil wood. Every species of ginkgo had died out by the Plicene (ie pretty recently, in the history of the ginkgo) ecept the one we know: the Ginkgo biloba or maidenhair tree.

They only grow in the wild in China these days, but were much more widespread millions of years ago. There’s also only one kind of ginkgo left anymore - the biloba - but there used to be more. The ginkgo is, in fact, a living fossil, that is, ‘an extant taxon that phenotypically resembles related species known only from the fossil record.’ [link] That is to say, something where the current living species looks very much like a species known from fossils. (Darwin coined the term!) One of my favourite living fossils - and they’re all rad AF - is this exploded-graboid-looking plant from Namibia.

Are the seeds toxic?

In large quantities, to humans, yes! Are they also a delicacy? Also yes! Would I ever eat them? No! And not just because I’m not a risk-taker! It’s also because the fruit smells absolutely terrrible when it falls from the tree and starts to rot. This is genuinley the reason we don’t have one in our garden. I don’t know how the prepared nuts smell, but again, I’m not a risk-taker.

Fun fact: the gingko fruit isn’t techinically a fruit because the tree is a gymnosperm, like a pine treee, and the nut doesn’t develop inside a fleshy ovary, which is how fruit trees (angiosperms) develop fruit. It’s most appropriate to call it a seed, and the squishy, smelly bit is correctly called “seed flesh.” But I’m just going to keep calling it a fruit; you get it.

But wait, there’s more! Ginkgo fruits smell so bad because they produce butyric acid as they ferment. Butyric acid is so-named becuase it apparently smells like rancid butter; I’ve never smelled rancid butter, but I’ve certainly smelled other things that contain the same compound - most notably, vomit. So, yes, they smell like barf. (Butyric acid also appears in parsnips!)

But why were ginkgos used in Art Noveau?

The short answer is: the Art Noveau movement developed out of a desire to create a literal “new art” style, one fusing design and function in a sinuous and naturalistic fashion. It took cues from, among other inspirations, Japanese art, and the Japanese had picked up the use of the ginkgo leaf and nut from the Chinese, which have used them in art for centuries.

This ginkgo fan took a lot of lovely photos of Art Noveau ginkgo decorations in Prague and Nancy.

Just one more thing!

Those stinky seed-flesh casings have to have provided the tree with some sort of evolutionary advantage, right? They must have attracted something to eat it and spread the fruit. If your first response to this is “oh, I bet this is a ghost mutualistic interaction, like the osage orange!”… you’re right! We can guess with a high degree of certainty that the barfy smell of the fruit attracted animals who were eating plants when the ginkgo biloba developed into its current evolutionary form. Animals that lived 270 milion years ago. You know. Dinosaurs. Fortunately for the ginkgo biloba, animals that survived the mass extinction event that killed the dinosaurs also liked to eat ginkgo seeds.

Although this does make me wonder what the species of ginkgo that didn’t survive to the modern day smelled like…

Keep asking questions!

Ax