Recent studies indicate that around the world, around 16500 plant species are in danger of extinction. The problem with these numbers is that this number is not complete yet; it only contains the known endangered plants on Earth. It’s estimated that more than 1 million plant species exist on Earth, and thus there are probably many more endangered plants than scientists know of. Some scientists believe that there are more endangered plants on Earth than animal species. The main reason for this is deforestation, which has caused many plant species to disappear.
One scientist describes the current situation as follows: “Plants are incredibly important for human life and form the basis of most ecosystems. We can hardly imagine our world without them”.
This is a quote from Dr. Stuart Pimm, Doris Duke Professor of Conservation Ecology at Duke University and leading plant conservation scientist.
To protect endangered plants, we must know which plants are most in danger. This list presents the top 20 most endangered plants on Earth as perceived by Plant List, a collaborative internet effort involving around 170 institutions and a large number of individual scientists all over the world.
The list is based on a set of five criteria: 1) number of locations, 2) population size, 3) population trend, 4) area of distribution and 5) degree of threat. The last criterion comes from the conservation status given to each species in the Red List of the IUCN.
Table of Contents
1. Gastrodia elata (Orchid) – Endangered
Gastrodia elata is an orchid native to New Zealand and Australia. The species has a very limited distribution area, which covers only about 10 locations. Furthermore, G.elata populations are small, and decline is ongoing.
2. Hibiscadelphus wilderanus (Hibiscadelphus – Critically Endangered
This Hawaiian plant is endemic to one location in Kauai, Hawaii. This species is endangered because there are only 27 mature plants left, and the population size has declined by more than 90% over the past 20 years.
3. Delissea rhytidosperma (Pawelu) – Critically Endangered
This plant is endemic to Oahu, Hawaii, and only lives in the Koʻolau Mountains. The population size is decreasing rapidly, which makes this species Critically Endangered on the IUCN Red List.
4. Adenophorus periens (Pendant Kihi Fern) – Endangered
This fern is endemic to the island of Kauai in Hawaii and has a limited distribution area on steep slopes. There are only 10 populations left, most of which have fewer than 100 plants. Furthermore, the species’ population size is decreasing rapidly.
5. Asplenium fragile var. insulare (Kauaʻi Spleenwort) – Endangered
This fern is endemic to Kauai, Hawaii, and only exists in the Alakai Plateau. The site where it can be found is very remote, which means that this plant has few chances of being seen. Furthermore, the population is decreasing rapidly, and only around 100 mature plants exist.
6. Echinomastus erectocentrus var. acunensis (Acuna cactus) – Endangered
This cactus is endemic to Mexico and lives in very small populations on limestone formations at high altitudes (> 2000 m) in Sinaloa and Nayarit. The main threats to this species are illegal collecting and habitat loss.
7. Cenchrus agrimonioides (Molokaʻi Sandbur) – Endangered
This grass is endemic to Hawaii, where it only occurs on the island of Molokai. Seven populations are known to exist, but scientists have estimated that there are likely less than 1000 mature individuals. Furthermore, this species’ population decreases rapidly, and the grass’s habitat is being destroyed by livestock and invasive plants.
8. Euphorbia haeleeleana (Koholā-Akoko) – Endangered
This flowering plant is endemic to the island of Kauai in Hawaii. It only occurs on steep slopes at high altitudes (> 1000 m), and there are very few mature individuals left, with most populations containing fewer than five plants. Furthermore, this species’ habitat is decreasing rapidly due to development and invasion by non-native plants.
9. Dracontium polyphyllum (Green Dragon) – Endangered
This species of Araceae occurs in the eastern United States and Canada. It is currently only found in small populations with very few mature individuals. Its habitat has been significantly reduced by invasive plants, habitat loss, and fragmentation.
10. Crinum thaianum (Thain’s Lily) – Critically Endangered
This species occurs in the Philippines and is only found on steep slopes with good drainage at low altitudes. There are just 20 mature individuals left, all under threat from continued habitat loss due to infrastructure development, quarrying and road construction. Furthermore, this plant is known to occasionally hybridize with other species of the same genus, potentially threatening its genetic diversity.
11. Pritchardia munroi (Loehman’s Prichardia palm) – Critically Endangered
This species of palm is endemic to Hawaii and only occurs on the island of Molokai. It has a very limited distribution area and is only found in old-growth forests. There are around 10 mature individuals left, and the rapid population decline is caused by habitat loss due to agriculture, competition with non-native plant species, human disturbances, and development.
12. Stenogyne cranwelliae (Kōkeʻe rosemary) – Critically Endangered
This species of flowering plant is endemic to Hawaii, where it only occurs on the island of Kauai. There are three populations known to exist, but scientists believe that less than 500 mature individuals are likely. Furthermore, this species’ habitat is decreasing rapidly due to invasive plants and human development.
13. Amaranthus brownii (Anaunau) – Endangered
This species of flowering plant is endemic to Hawaii and only occurs on the islands of Kauai and Oahu. Its population has been declining rapidly, with all mature individuals found in a single location. Furthermore, the invasive black twig borer beetle often attacks this plant, and its habitat is constantly threatened its habitat.
14. Phyllostegia bracteata (No Common Name) – Endangered
This species of flowering plant is endemic to Hawaii and only occurs on the islands of Kauai and Oahu. Its population has been declining rapidly, with all mature individuals found in a single location. Furthermore, the invasive black twig borer beetle often attacks this plant, and its habitat is constantly threatened its habitat.
15. Ochrosia haleakalae (Hāleakala ʻōhiʻa) – Endangered
This species of flowering plant is endemic to Hawaii and only occurs on the island of Maui. Its population has been declining rapidly, with all mature individuals found in just two locations. Furthermore, this species’ habitat is constantly threatened by fire and invasive plants.
16. Doryopteris angelica (No Common Name) – Endangered
This fern species occur in the United States and Mexico, where it only grows on the island of Oahu. Less than 100 mature individuals are left, and invasive non-native plant species are constantly degrading their habitat. Furthermore, the population is declining rapidly due to a lack of recruitment.
17. Neraudia ovata (Hoope) – Critically Endangered
This species of flowering plant occurs in Hawaii and only occurs on the island of Molokai. There are just five individuals left, and this species’ habitat is constantly being degraded by invasive plants, fire, and human activity. Furthermore, there are no natural pollinators of this plant, and the population is rapidly declining.
18. Delissea rhytidosperma (No Common Name) – Endangered
This species of flowering plant only occurs in Hawaii and only on the island of Kauai. There are just five individuals left, and its habitat is constantly being degraded by invasive plants, fire, and human activity. Furthermore, there are no natural pollinators of this plant, and the population is rapidly declining.
19. Hibiscadelphus wilderianus (Hāpuʻu) – Endangered
This species of flowering plant is endemic to Hawaii and only occurs on the island of Kauai. Two populations are known to exist, but scientists believe that there are likely less than 1000 mature individuals. Furthermore, this species’ habitat is constantly threatened by invasive plants and competition with non-native plant species.
20. Hibiscus brackenridgei (Pilo) – Endangered
This species of flowering plant is endemic to Hawaii and only occurs on the island of Kauai. Two populations are known to exist, but scientists believe that there are likely less than 1000 mature individuals. Furthermore, this species’ habitat is constantly threatened by invasive plants and competition with non-native plant species.
FAQ’s
Q: What are endangered plants?
A: Endangered plants are species that have been categorized as facing a very high risk of extinction shortly. This is usually due to threats associated with human activity, such as habitat loss or degradation. Other common threats include exploitation by man for medicine or food, invasive species, and climate change.
Q: Which plant is the most endangered?
A: As of 2016, there are currently 6741 species categorized as threatened (which includes critically endangered, endangered, and vulnerable). The most threatened group of plants on Earth is the cycads – these slow-growing seed-producing plants occur in tropical and subtropical regions, and some live for hundreds or even thousands of years. About 95% of cycads are threatened with extinction, making them the most endangered group on Earth.
Q: How many plants are on the endangered list?
A: More than 1.7 million plant species have been described, but just 20,000 of them are currently on the endangered list. However, scientists estimate that there are around 15-30% more plants on Earth than previously thought – this means that up to 50,000 plants may be under threat!
Q: What are the endangered plants in the Philippines?
A: There are indigenous plants in the Philippines categorized as endangered by the International Union for Conservation of Nature, but none of these species currently grow in the wild. Three (Aspidopterys philippinensis, Begonia paradisicola, and Eupomatia macrocarpa) have not been seen in more than 50 years, and there is very little chance that they still exist in the wild. However, some species (such as Begonia chiapensis) have been moved from vulnerable to endangered due to uncontrolled collection by plant collectors.
Conclusion
If you’re looking to get more involved in environmental conservation, this list of the top 20 most endangered plants can help. Read on for a rundown of what each plant is and why it needs our attention, as well as how we can protect them. As a bonus, I’ve provided some resources that will teach you even more about these species so that you’re ready to take action when needed! You’ll be amazed by all the incredible stories behind these beautiful plants–and maybe inspired enough to turn your backyard into a haven for wildlife too!
