🌿Ferns: The superpowers of living fossils

Fifty million years ago, a tiny fern called Azolla filiculoides grew in mats over open water in the Arctic Ocean, flourishing like that for 800,000 years. (It now turns up in [Arctic ice cores in vast quantities]( This was a significant event not just for fern domination but for the globe: Paleobotanists call it the “Azolla event,” because the Azolla mats sucked up 10 trillion tons of carbon dioxide during that period—well over 200 times the total amount of carbon dioxide humans currently release into the atmosphere [every year](. The event played a role in the abrupt shift from a very warm planet to the cool one we now inhabit. Scientists have wondered for years if Azolla could be [harnessed to cool the planet again](. But the genetics of the fern were poorly understood, until just recently. Last month, Azolla became the [first fern to have its genome completely sequenced]( opening the wild world of ferns up to a new level of scientific understanding. It’s been a long time coming (ferns are notorious for having massive genomes, so they are particularly arduous to sequence) but fern science has been delightfully weird for centuries. 🐦 [Tweet this!]( 🌐 [View this email on the web]( Brought to you by [Quartz Obsession] Ferns August 06, 2018 Old fronds --------------------------------------------------------------- Fifty million years ago, a tiny fern called Azolla filiculoides grew in mats over open water in the Arctic Ocean, flourishing like that for 800,000 years. (It now turns up in [Arctic ice cores in vast quantities]( This was a significant event not just for fern domination but for the globe: Paleobotanists call it the “Azolla event,” because the Azolla mats sucked up 10 trillion tons of carbon dioxide during that period—well over 200 times the total amount of carbon dioxide humans currently release into the atmosphere [every year](. The event played a role in the abrupt shift from a very warm planet to the cool one we now inhabit. Scientists have wondered for years if Azolla could be [harnessed to cool the planet again](. But the genetics of the fern were poorly understood, until just recently. Last month, Azolla became the [first fern to have its genome completely sequenced]( opening the wild world of ferns up to a new level of scientific understanding. It’s been a long time coming (ferns are notorious for having massive genomes, so they are particularly arduous to sequence) but fern science has been delightfully weird for centuries. 🐦 [Tweet this!]( 🌐 [View this email on the web]( P. F. Lu Look at this! A whole Azolla plant, leaves and all, is the size of an M&M, or a human fingernail bed. Each of its leaves is the size of a gnat, those tiny black dots that fly around like dust motes. It also grows in lovely scalloped layers, like a flapper’s dress (for a very tiny flapper). By the digits [10,500:]( Approximate number of fern species on Earth today [100:]( Years that a resurrection fern can remain completely dehydrated and still make a full recovery [65:]( in feet that a tree fern trunk can reach [60:]( Longest number of minutes fern sperm have been recorded swimming [5:]( of minutes to sauté baby fiddlehead ferns so that they become delicious [$22,000:]( Amount fern researchers raised on a crowdfunding platform to fund the mapping of the first fern genome Brought to you by Hilton Honors Travel like a pro. --------------------------------------------------------------- Flight canceled? Need to check out in a hurry? Forgot your charger? Master traveling in six steps with these must-know tips.[Click here to read on qz.com]( Giphy Fast fact! Ferns are some of the oldest land plants still on earth, older than flowers, or even seeds. They appeared on earth roughly 400 million years ago—millions of years before the dinosaurs. Ancient plants, modern superpowers --------------------------------------------------------------- Sucking carbon out of thin air isn’t the only cool thing ferns can do. During the process of sequencing the Azolla’s genome, the researchers, led by Cornell University plant evolutionary biologist Fay-Wei Li and Duke University evolutionary botanist Kathleen M. Pryer, found a fern-specific protein known to repel insects, likely adapted into the plant’s genome from bacteria. “In general, insects don’t like ferns, and scientists wondered why,” Li said in a release. Locating the source of ferns’ natural insect resistance could have “huge implications for agriculture,” he said. [Some modern industrial pesticides]( are [linked to human health problems]( and contribute to [air]( and [water pollution]( a fern-protein-based pesticide would be a massive breakthrough. Azolla’s shape also contains specialized little indents where it houses cyanobacteria, a form of blue-green algae that acts as a nitrogen fixer—that is, it converts nitrogen in the atmosphere into a fertilizer. The fern hosts the bacteria, providing it with sugary fuel, and in doing so, helps make its own fertilizer. Farmers throughout Asia, [particularly in China and Vietnam]( already knew that: They have used Azolla as a form of fertilizer in rice fields for [more than 1,000 years](. In their [Nature Plants]( paper, Li and his team identified the genetic underpinning of the fern and the cyanobacteria’s symbiotic relationship. “With this first genomic data from ferns, science can gain vital intelligence for understanding plant genes,” Li said. “We can now research its properties as a sustainable fertilizer and perhaps gather carbon dioxide from the atmosphere.” Fay-Wei Li Pop quiz The tiny Azolla fern is also known as what? The amoeba fernThe zygote fernThe mosquito fernThe itsy-bitsy spider fern Correct. Incorrect. If your inbox doesn’t support this quiz, find the solution at bottom of email. Now you know Ferns have swimming sperm --------------------------------------------------------------- Ferns have remarkably complex life cycles. Before they grow the leafy fronds we all know, they have a completely separate life as a gametophyte fern. In this stage, ferns are a tiny plant just one cell thick—not remotely recognizable. Their reproduction is relatively unusual for the plant world: The male gametophyte fern releases sperm that swim in water, looking for female gametophyte fern eggs to fertilize. Fern sperm are [shaped like tiny corkscrews]( and are endurance athletes—they can swim up to 60 minutes. But the swimming sperm alone isn’t the most amazing thing about fern reproduction. Research is emerging to suggest that ferns compete for resources against other ferns by emitting a hormone that causes the sperm of neighboring fern species to slow down. Slower sperm means less of that species survive, so the sabotaging fern can enjoy more of whatever is scarce, be it water, sunlight, or soil. Let that sink in a minute: Ferns can remotely interfere with other ferns’ sperm. Incredibly salty plant activity. Scientists are just beginning to wrap their heads around this fact. “This is brand new,” [Eric Schuettpelz]( a research botanist at the Smithsonian’s National Museum of Natural History in Washington, DC, told Quartz. “We know it’s the plant hormone but no idea how it works,” Schuettpelz said. [Eddie Watkins]( a fern botanist at Colgate University, just [presented an early paper]( on the phenomenon at a botanist conference this month. Reuters/Luke MacGregor Brief history When ferns sprouted invisibility cloaks --------------------------------------------------------------- Ferns’ second life stage is the one we’re all familiar with: When the gametophyte sperm fertilizes the gametophyte egg, the result grows into a baby fiddlehead fern, which are delicious earthy treats to eat in early spring. If they are left unconsumed, the fiddle head unfurls into a frondy fern. If you look on the underside of a fern frond, depending on the time of year, you might find rows of dusty spots in shades of yellow, brown and orange. Those are spores, and they’re how ferns in this life stage reproduce—the spores germinate into gametophyte ferns that release those swimming sperm and start the cycle all over again. But this spore stage completely stumped European botanists for hundreds of years. During Shakespeare’s time, people believed all plants reproduce via seeds. And since fern seeds never seemed to appear, ferns must have been magic. “No one had ever seen a fern seed before so they thought they were invisible,” [Nathalie Nagalingum]( the Chair of Botany at the California Academy of Sciences, told Quartz. And because another dominant theory at the time suggested that the physical characteristics of plants were clues about what the plants could be used for, people believed finding these invisible seeds would grant humans the power of invisibility. Catching a fern seed, then, became a complicated mystical pursuit: People believed the seed could only be caught as it fell at midnight on Midsummer’s Eve (June 23). “You could catch it by stacking 12 pewter plates beneath a fern leaf; the seed would fall through the first 11 plates and be stopped by the 12th. If you came up empty-handed, it was because goblins and fairies, which were allowed to roam freely that one night of the year, had snatched the seed as it fell,” explains [Robbin C. Moran]( of the New York Botanical Garden. This explains why, in Shakespeare’s Henry IV, a character intending to rob a rich merchant brags that he and his band won’t be caught; “We have the receipt of fern-seed, we walk invisible.” Scientists didn’t realize until the 1800s that ferns use spores, not seeds, to reproduce, and so the myth persisted for several hundred years. Quotable “Cats need a balanced diet. Meat, eggs, fruit, bread, vegetables, and an occasional Boston fern for dessert.” [—Garfield, the cartoon cat]( Reuters/Srdjan Zivulovic Fun fact! A hundred million years ago, Antarctica was covered [with vast fern forests](. Trends of yore Fern fever --------------------------------------------------------------- Victorian England caught fern fever—or “[pteridomania]( they caught it bad. From the 1850s to the 1890s, ferns began appearing on everything from pottery to gravestones in the UK, and fern collecting became all the rage, particularly among women. Collecting ferns from forests was a rare activity that women were permitted to do on their own. “They were totally obsessed,” says Nathalie Nagalingum of Cal Academy. People would bring them back to their homes and display them in glass terrariums, to protect them from the ruinous air pollution in UK cities. It sounds quaint but the passion had a dark side: Fern collecting became so popular that it stripped native species from swaths of their rural habitats, particularly in Scotland. Giphy Who's who among ferns --------------------------------------------------------------- Ferns are insanely diverse. Most people think of the big, floppy tropical ferns first, but there are species of ferns that grow almost everywhere on earth. Desert ferns, for example, are a very hardy bunch. Other ferns grow on rocks, or high up in trees, or climb like vines. Tree ferns can grow more than [65 feet high]( Osmunda ferns have underground tubers that can be up to 70 pounds, and other ferns are miniscule, like the tiny Azolla. So next time you look at that Boston fern hanging by your window, remember: It’s part of a vast, complicated, sperm-swimming story of adaptation and resurrection, which stretches back to long before the flowers on your table were even a twinkle in evolution’s eye. This one cool trick! Zombie ferns in space --------------------------------------------------------------- Resurrection ferns grow on the branches of oak trees, and can [almost completely dehydrate]( in times of drought, shrinking down into a dead-looking crisp. But just add water and the fern springs right back to chartreuse-colored life. A resurrection fern can remain in its dried state for [more than 100 years]( and still fully rehydrate when rains return. Almost nothing else on Earth can do that. But the resurrection fern can do it even not on Earth: In 1997 NASA [launched a dehydrated resurrection fern]( into space on the shuttle Discovery, to watch it rehydrate in zero gravity. It performed fabulously. Giphy Poll What's your preferred houseplant? [Click here to vote]( Frantic for fernsSucker for a solid succulentFicus or bust The fine print In Friday’s poll about [pigeons]( 52% of you said “hey, it’s their planet too.” Today’s email was written by [Zoë Schlanger]( edited by [Jessanne Collins]( and produced by [Luiz Romero](. 📣Let's talk! Discuss this topic now with other [Obsession Obsessives on Reddit]( take us down a 🐰🕳 of your own! Sound off! ✏️ [What did you think of today’s email?](mailto:obsession%2Bfeedback@qz.com?cc=&subject=Thoughts%20about%20ferns&body=) 💡 [What should we obsess over next?](mailto:obsession%2Bideas@qz.com?cc=&subject=Obsess%20over%20this%20next.&body=) 🐰 [What have you been obsessing over this week?](mailto:obsession%2Bprompt@qz.com?cc=&subject=Take%20us%20down%20a%20rabbit%20hole.%20&body=) 📬 [Forward this email to a friend](mailto:replace_with_friends_email@qz.com?cc=obsession%2Bforward@qz.com&subject=%F0%9F%8C%BFFerns%3A%20The%20superpowers%20of%20living%20fossils&body=Thought%20you%27d%20enjoy.%20%0ARead%20it%20here%20http%3A%2F%2Fqz.com%2Femail%2Fquartz-obsession%2F1349113) Keep obsessing 😍 Revisit the Quartz Obsession on: 🌱 [Succulents]( 👃 [Musk]( 🤢 [Tardigrades]( The correct answer to the quiz is The mosquito fern. Enjoying the Quartz Obsession? [Send this link]( to a friend! If you click a link to an e-commerce site and make a purchase, we may receive a small cut of the revenue, which helps support our ambitious journalism. See [here]( for more information. Not enjoying it? No worries. [Click here]( to unsubscribe. Quartz | 675 Avenue of the Americas, 4th Fl | New York, NY 10011 | United States [Share this email](