This article was originally a topic for weird Halloween plants series. After all, the cycas is a palm-like cousin of conifers: it’s pretty special! Then I came across the term “living fossil” in my research and… I kind of “went nuts”.
Banished from my Halloween series, this text has been revised and transformed into a history class (but not the boring kind!). We’ll be talking about cycas, its history, and why the term “living fossil” should be banned from your vocabulary.
The Short Evolutionary History of Cycas
Cycas is shaped like a palm tree and belongs to the order Cycadales, which currently comprises some 350 species. The first representatives of this order are thought to have appeared around 300 million years ago. Gymnosperms had only recently come into existence, and the cycad was one of the first of this large group, which includes conifers, to exist.
Obviously, the cycas of the time were not the same as today. This period is known as the Carboniferous, and stretches from 359 to 299 million years ago. It was a very different world from what we know today: horsetails and tree ferns dominated the plant landscape, the air contained more oxygen than ever before, and amphibians and insects were gigantic.
Three-metre dragonflies zigzagged between ten-metre-high horsetails!
It was in this environment that the first Cycads appeared, and a few million years later, in the Permian, the diversity of this order exploded.
In the Triassic, from 252 to 201 million years ago, gymnosperms dominated the plant landscape. Then came the Jurassic and Cretaceous periods, when the dinosaurs lived. During this period, cycads were so abundant that they were one of the main sources of food for animals. Of course, their leaves were undoubtedly softer than those of our living-room cycas!
Cycas Is Dead, Long Live Cycas
Since then, many species have disappeared, both plant and animal. Cycas is much less common now than it was then, and there has been no other period when it has diversified to produce new species in large quantities.
However, the species we have today still resemble the species of yesteryear. In fact, at first glance… they look the same! So… if they look like dinosaur cycads, that means there’s been no evolution since, that they’re a kind of… living fossil!
NO!!!
And therein lies the problem with the term. Modern cycads are VERY different from fossil cycads. Even if their general shape is very similar, that doesn’t mean they’re identical, or that they haven’t evolved: on the contrary!
Do you really think that a tree living in an environment where the air is 35% oxygen could live today on a meagre 20%? No! Cycas, like many other species, may resemble its ancestors, but it’s not the same. It has evolved as much as any other 300-million-year-old species.
That’s why the expression “living fossil” has no place in the vocabulary of living things. It’s a reductive name that suggests a species hasn’t evolved, or even that it’s doomed to disappear! To limit misunderstandings, this now obsolete expression has been replaced by “panchronic species”, and simply designates a living species resembling other extinct species.
Why the Outburst?
Because the expression “living fossil” is used everywhere and never really understood, leading to false conclusions. A few examples of what I’ve heard about these famous fossils?
“Crocodiles were around when the dinosaurs were, and they haven’t evolved since! They’re living fossils.”
Uh… yes, there were crocodiles, just as there were dragonflies, but not the same species as today… Why should the crocodile be more fossilized than the dragonfly? They HAVE evolved, even if their general shape is the same at first glance.
“The tuatara is the last species of its order, doomed to disappear: it’s a living fossil.”
AAAHHHRRGG!!! It hurt writing that one! OK, other species are extinct, OK, maybe it’s threatened with extinction, but that has nothing to do with being a pan-chronic species at all!
“[Ginkgo biloba] is a living fossil and has been around (unchanged) for 270 million years.”
This one comes from Larry himself (I’m sorry Larry, you didn’t know, but I don’t blame you!). The species may be the only one to have survived the ice ages a few thousand years ago, and may resemble older species, but it’s still a present-day, pan-chronic species, not 270 million years old.
In short, the expression “living fossil” is rubbish.
Cycas in your living room
It’s a beautiful, low-maintenance, slow-growing houseplant. I’ve had one for two or three years and I love it! Mind you, when I say slow growth: it hardly moves at all! I don’t think it’s lost a single leaf yet! It loves the sun, so I put it outside in summer, progressively in full sun (it’s a desert or tropical plant, depending on the species, after all!), and I water it abundantly when the soil is very dry, hardly at all in winter.
Don’t forget that it’s almost a conifer: the needles are covered in wax, and it loses much less water than the majority of leafy plants we see in our homes.
Otherwise, a very light, draining potting soil. In nature, it lives in sand or rocks: it’s hard to do better in terms of drainage!
That’s all there is to it! Really an easy plant. A very pretty plant, alive and not at all fossilized…!
If you’d like more information on growing cycas, I recommend this very detailed article by Larry Hodgson. You’ll notice several discrepancies in the story at the beginning of the article, including dates and classification: that’s because the article is nearly 10 years old, and discoveries and knowledge are pouring in from our modern world! I invite you to join me in chuckling when he mentions the “living fossil”!
One thing not mentioned in the article, so I will throw it out there is ALLl parts of the sago palm are HIGHLY toxic to pets and can be fatal .
What an odd group. The common Cycas revoluta was trendy in the 1980s, so many were planted into situations that they were not appropriate to. I grew many here from pieces of large specimens that needed to be removed because they were too big for their situation on the edge of a sidewalk. We could not dig them up intact without ruining the concrete, so we cut them into pieces. Now, we have too many to accommodate within our landscapes. We have been sharing them with friends and neighbors.