When it comes to extinction, plants just don't get as much attention as animals: It's always "save the whales" this or "save the rhinos" that. Sure, those species are important, and we should do everything we can to ensure they're around for future generations; however, there are many, many plants that are just one drought or disease away from being wiped off the face of the Earth. Maybe if people just knew a little more about the amazing plants we've already lost, a slogan like "save the Western Underground Orchid" might soon show up on a bumper sticker near you.
So what makes a plant go extinct? Some risk factors are natural: The type of soil plants need to grow, the organisms they rely on to survive, and the ways they reproduce or spread their seed can all affect their ability to stick around. Humans are to blame for other causes, including loss of habitat or pollinators, in addition to the introduction of competing species, diseases and pests. People might also collect endangered plants food or medicine [source: Forest Service].
Today, these threats have put at least 22 percent of plants at risk of extinction, with some species reduced to fewer than 100 specimens in the wild [sources: Jowit, Dasgupta]. So what's the big deal? Maybe nothing — or maybe we might lose a plant that can cure cancer. With that sobering thought in mind, let's look back at some of the plants we've already lost.
Scientists know about a lot of really old, extinct plants thanks to fossil imprints, but they discovered Strychnos electri in an even cooler way. It all started in 1986 when Oregon State University entomologist George Poinar took a field trip to the Dominican Republic and collected about 500 specimens encased in amber, or hardened tree resin. A few of the organisms trapped in the hardened chunks of yellowy-clear amber were flowers, but, being a bug guy, Poinar focused on the insects. It wasn't until 2015 that he decided somebody might also want to look at the flowers, and he knew just the person for the task — Dr. Lena Struwe, a botanist at Rutgers University.
Struwe specialized in the type of plants from which the flower came: Strychnos, a group of toxic flora from which the rat poison strychnine is derived. The botanist compared it to hundreds of specimens before concluding it was an extinct variety that lived some 15 to 45 million years ago. And the name "electri?" It comes from the Greek word "elektron," meaning "amber" [source: BBC].
Long before it went extinct, the St. Helena olive was a tough plant to track down. To see one of these small trees with pale pink flowers, you had to travel all the way to the small island of Tristan da Cunha, St. Helena, a British territory in the South Atlantic Ocean about 1,200 miles (1,931 kilometers) off the coast of Angola. They sat atop the island's east central ridge of mountains and had become exceedingly rare even as early as the 19th century. At that time just 12 to 15 trees were known to exist on the ridge's highest point, Diana's Peak — so few, in fact, that people soon just figured it had disappeared completely. But there, on one of the mountain's precipitous cliffs, one hardy survivor was discovered in 1977. Was there still hope?
Sadly, no. The St. Helena olive just wasn't able to overcome the longstanding threat of deforestation, and the fact that they weren't able to self-fertilize didn't help their chances, either. Further complicating the tree's problems were pests and fungal infections that were sometimes carried by the seeds. That last wild St. Helena's olive died in 1994, and by December 2003 all those raised by humans had died as well [source: Cairns-Wicks].
Imagine a densely packed stand of treelike plants with scaly bark. The trunks reach as high as 100 feet (30 meters) into the air, but only the tallest specimens have branched out to reveal clusters of long, narrow, grasslike leaves. The rest just look like tall telephone poles with an alligator-skin texture. These are Lepidodendron, a now-extinct plant that inhabited low-lying, swampy areas some 299 to 359 million years ago during the Carboniferous period.
Lepidodendron were a little strange compared to today's plants. Despite their tall stature, they weren't very woody; rather, they were supported by a stiff, exterior barklike structure. This rigid outer shell had diamond-shaped leaf scars that formed as the plant grew and provided it with fuel through photosynthesis. Later, this unique scaly texture came to characterize Lepidodendron fossils, which 19th-century amateur fossil hunters displayed at fairs, claiming they were from the skin of prehistoric giant lizards and snakes.
At the end of its 10- to 15-year life, Lepidodendron finally branched out and sprouted leaves. This is when it reproduced, too, though probably just once. Still, the plant had an impressive reign before conifers and other plants replaced it at the dawn of the Mesozoic era. It is now one of the most common fossils found in Late Carboniferous rock [source: Kenrick and Davies].
Botanist John Bartram and his son William were traveling through Georgia in 1765 when they discovered a beautiful shrub with fragrant white flowers along the banks of the Altamaha River. They named it the Franklin tree after their buddy, founding father and kite enthusiast Benjamin Franklin. After a return trip in the 1770s, William noticed that the tree grew only on a couple of acres by the river and nowhere else. Either concerned about its survival or charmed by its beauty (or both), William took some plants and seeds home with him to Pennsylvania. We're lucky he did, because the last confirmed sighting of a Franklin tree happened just a few decades later in 1803.
Today, the Franklin tree is extinct in the wild, but, thanks to William's specimens, it's not quite lost to history. Franklinia alatamaha has become a popular landscaping plant, which isn't surprising given its unique beauty. About as wide as it is tall (about 15 feet [4.6 meters]), this small tree boasts 3-inch (7.6-centimeter) white flowers with a cluster of bright yellow stamens that bloom from late summer until the first frost. In fall the dark green leaves seem to catch fire, turning brilliant shades of red, orange or pink. It's become so beloved that it represented the South on a 1969 U.S. postage stamp.
But will the Franklin tree ever return to the wild? There are efforts to replant the trees in the area where William found it some 250 years ago — so we'll see! [source: Merkle]
Antarctica isn't exactly a place you associate with lush, green trees, shrubs and flowering plants. In fact, there are only two flowering species on the whole continent: Colobanthus quitensis and Deschampsia antarctica. But there were times when the icy continent showed a lot more green, like the Late Permian, an era marked by the melting of the great ice sheets and the existence of cool, wet weather across Antarctica. It was then that Glossopteris thrived [source: Kenrick and Davies].
Because scientists have never found large parts of the Glossopteris preserved intact, they don't know exactly what it looked like. Their best guess is that it was probably a big shrub or a small tree. Fossils of the oval-shaped leaves, however, are fairly common, with some measuring up to 3.3 feet (1 meter) in length. The large number of preserved leaves suggests that the plants were deciduous, meaning they dropped their leaves in the fall and sprouted new ones in the spring [source: Speer].
Glossopteris fossils are also found in South America, Africa and Australia because those continents were once joined with Antarctica in a giant continent called Gondwana. Despite this apparent widespread success, the plant went extinct about 245 million years ago when a warmer, drier climate settled over the region during the Triassic period [source: Francis and Thorn]. Who knows — with our climate experiencing another warming trend, maybe we'll see plants like Glossopteris break through the Antarctic soil once again.
While you might want to cry knowing another plant has gone extinct, that's not how this small wild pansy got its name. It's actually named after the French community of Cry, where the flower was first discovered in 1860 along the Canal de Bourgogne. Standing just 1.5 to 5 inches (4 to 12 centimeters) tall, it featured thick, light green leaves and light violet flowers that bloomed from May to June. The Cry violet preferred the warm, sunny, south-facing sides of the area's limestone hills, where it was last spotted in 1927. After that, some people may have tried to raise them in their gardens, but even these efforts failed by 1950. Despite many attempts to locate a survivor, no one has seen one since [sources: Lombard and Bajon, Juillet].
Viola cryana was never a very common species, though as botanists will tell you, that alone doesn't necessarily doom it to extinction. What brought down this little plant was quarrying of the very limestone in which it liked to live and, ironically, over-collection by botanists [source: Juillet].
In east central Arizona's Petrified Forest National Park you'll find an odd sight: Large sections of fossilized trees strewn across the dry desert floor. The Navajo believed them to be the bones of a giant killed by their ancestors, while the Piute saw them as arrow shafts from the thunder god. In 1888 Smithsonian curator F.H. Knowlton identified them as a species of extinct trees he called Araucarioxylon arizonicum, but scientists now believe the term actually describes many species of extinct trees that flourished in the region some 200 million years ago [sources: Knowlton, NPS, Conover].
They were giant conifers with trunks measuring 10 feet (3 meters) in diameter that once reached up to 194 feet (59 meters) into the sky before they were toppled by ash and debris flows caused by a nearby volcanic eruption [source: Ash and Creber]. It was these destructive flows, however, that encased the trees and crystallized their remains, ultimately preserving them for us to enjoy millions of years later [source: Conover].
Interestingly, the fossils themselves almost went extinct, so to speak, because of rampant collecting. It all started when General William Tecumseh Sherman requested an expedition to collect two large specimens for the Smithsonian. After that, opportunistic businessmen swarmed the area, hauling off sections of the fossilized trees to craft into things like tables, tiles, jewelry and mantels. While the creation of a national monument in 1906 and a national park in 1962 helped slow the plundering, an estimated 12 to 14 tons of petrified wood is illegally snatched each year by tourists [source: Conover].
Here's a nightmare scenario for a lot of people: You get up in the morning, and you're out of coffee. The grocery store is out of coffee. Starbucks is out of coffee. The whole world, you come to find out, is out of coffee — it's gone extinct! Don't worry, we're not there yet, but scientists are starting to get a little worried. One study found that under current warming trends, as much as 99.7 percent of coffee-growing areas will be too hot to grow Arabica, the bean that fuels 70 percent of the world's java, by 2080 [sources: Siddle and Venema, CBC News].
For the sake of all our mornings, let's hope Arabica doesn't go the way of lemblinii, one of 40 Coffea species related to the popular bean [source: Koziell and Sanders]. French botanist Auguste Chevalier first described lemblinii in 1907, and it hasn't been seen since. The small bush, with white blossoms and peeling, papery bark, once grew in the forests of the Vallee de l'Agnieby region of the Ivory Coast. It grew up to 3.3 feet (1 meter) in height and flowered in January — at least the one Chevalier found did. While it's hard to know for sure, lemblinii is believed to be extinct; all that remains of the species is a single herbarium specimen [source: Poorter, Bongers, and Kouame].
Some ancient plants have close modern relatives. That's the case with calamites, an extinct, tree-sized plant that proliferated during the Carboniferous period some 250 to 360 million years ago. They looked like today's horsetails, but on steroids [source: Arens].
Calamite trunks consisted of hollow segments, giving them the outward appearance of bamboo. At the dividing ring between each segment, slender branches slanted upwards, branching a few more times before terminating in bunches of needlelike leaves. The whole plant stretched 33 to 66 feet (10 to 20 meters) high and was anchored by a massive rhizome, or underground stem, that allowed it to sprout clones of itself (it was the only plant of the period known to have that ability). Common on the sandy banks of rivers, calamites probably grew close together so they could support one another. Otherwise they tended to break fairly easily, which is actually one reason why so many fossils remain. Sediment would quickly fill the hollow, broken trunks, and as the outer tissues rotted away the inner cast remained [sources: Kenrick and Davies, University of Waterloo].
Few plants are as mysterious to scholars as Silphium. Described as a giant fennel, this plant was native to the Cyrene area (now part of Libya) where it was apparently quite abundant. The historical record didn't have much to say about it, though, until a group of Greek colonists arrived in 630 B.C.E. and went absolutely bonkers over it. They got rich selling the plant all across the Mediterranean and developed such an affinity for it that they put it on their coins.
The question was: Why exactly was Silphium so popular? Historians have a number of theories, including that it was used as a garnish for food or as a medicine to treat common symptoms like fever and abdominal pain. But for many scholars, those don't seem like important enough uses to warrant such a craze. The real reason might have been a bit more taboo: Maybe it was used for birth control.
Whatever the case may be, we'll never know because there isn't any Silphium left to test. Sheep might be to blame for overgrazing the plants, or the Cyreneans may just have picked it all. Either way, the natural philosopher Pliny the Elder said someone found the last stalk during his lifetime and gave it to the Roman emperor Nero. If that's true, it places the extinction date somewhere around 50 C.E. [source: McCarthy].
How can plants defend themselves against insects? Learn more about a new tomato study in this HowStuffWorks article.
Author's Note: 10 Plants Lost to History
When I wrote in the introduction that animals get all the attention when it comes to extinction, it wasn't just for the sake of a catchy hook. There is way less information in the popular media about extinct plants than there is about extinct animals. I guess plants just aren't as cute and cuddly, and you just can't anthropomorphize them (talk about them like they're human) as easily. That's too bad because we've already lost some truly amazing plants, and we're going to lose many more if we don't start giving them attention, too!
More Great Links
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- Ash, Sidney and Geoffrey T. Creber. "The Late Triassic Araucarioxylon Arizonicum Trees of the Petrified Forest National Park, Arizona, USA." Palaeontology. Vol. 43, Iss. 1. Pages 15-28. 2000. (April 27, 2016) http://onlinelibrary.wiley.com/doi/10.1111/1475-4983.00116/pdf
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- BBC. "Extinct Plant Species Discovered in Amber." Feb. 15, 2016. (April 25, 2016) http://www.bbc.com/news/science-environment-35582991
- Cairns-Wicks, R. "Nesiota elliptica." International Union for Conservation of Nature and Natural Resources. 2004. (April 26, 2016) http://www.iucnredlist.org/details/37598/0
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- Conover, Adele. "The Object at Hand." Smithsonian Magazine. June 1997. (April 27, 2016) http://www.smithsonianmag.com/science-nature/the-object-at-hand-8-137955135/?all&no-ist
- Conservatoire Botanique National Du Bassin Parisien. "Viola cryana Gillot, 1878." April 23, 2016. (April 27, 2016) http://cbnbp.mnhn.fr/cbnbp/especeAction.do?action=pres&cdNom=129545
- Dasgupta, Shreya. "The 9 Rarest Plants in the World." BBC. Nov. 21, 2014. (April 25, 2016) http://www.bbc.com/earth/story/20141121-the-rarest-plants-in-the-world
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- Francis, Jane and Vanessa Thorn. "Fossils, Plant." "Encyclopedia of the Antarctic." Ed. Riffenburgh, Beau. Routledge. 2007.
- Jowit, Juliette. "One in Five Plant Species Faces Extinction." The Guardian. Sept. 29, 2010. (April 25, 2016) http://www.theguardian.com/environment/2010/sep/29/plant-species-face-extinction
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- Kenrick, Paul and Paul Davis. "Fossil Plants." Smithsonian Books. 2004.
- Knowlton, Frank H. "New Species of Fossil Wood (Araucarioxylon arizonicum) from Arizona and New Mexico." Proceedings of the United States National Museum. 1888. (April 27, 2016) http://si-pddr.si.edu/dspace/bitstream/10088/13045/1/USNMP-11_676_1888.pdf
- McCarthy, Susan. "Don't Worry, Darling, I Have Giant Fennel." Salon. July 1, 1999. (April 29, 2016) http://www.salon.com/1999/07/01/fennel/
- Merkle, Scott A. "Franklin Tree (Franklinia alatamaha)." New Georgia Encyclopedia. Dec. 2, 2015. (April 25, 2016) http://www.georgiaencyclopedia.org/articles/geography-environment/franklin-tree-franklinia-alatamaha
- National Park Service. "What's in a Name? The Araucarioxylon Problem." 2016. (April 27, 2016) https://www.nps.gov/pefo/whatname.htm
- Poorter, L. et al., eds. "Biodiversity of West African Forests: An Ecological Atlas of Woody Plant Species." CABI. 2004.
- Siddle, Julian and Vibeke Venema. "Saving Coffee from Extinction." BBC. May 24, 2015. (April 28, 2016) http://www.bbc.com/news/magazine-32736366
- Speer, B.R. "Introduction to the Glossopteridales." March 15, 1997. (April 26, 2016) http://www.ucmp.berkeley.edu/seedplants/pteridosperms/glossopterids.html
- University of Waterloo. "Calamite Fossils." 2016. (April 29, 2016) https://uwaterloo.ca/earth-sciences-museum/resources/calamite-fossils