9 Extinct Plants: Reasons and Conservation Efforts

Disappearing flora and fauna is a normal process of evolution. However, the rates of extinct plants and animals are increasing faster than evolution. And even before their discovery, they are at risk of extinction. 

Despite our limited knowledge about the world's plants, a botanical community keeps track of collected specimens. Botanical communities like the New York Botanical Garden have herbarium collections, which help us keep track of extinct species. The collection records plants’ history throughout their lifecycle and helps plant conservation groups revive herbarium specimens. 

This article will explore the reasons for plant extinction and ten species of extinct plants. We will also discuss conservation efforts to preserve new and existing species and restore extinct plants. 

Reasons For Plant Extinction  

Various factors are responsible for the many plant extinctions happening worldwide. However, humans and their activities are constants in these factors. 40% of plant life is going extinct. We don’t even know some plant identifications yet, but they are about to be extinct.

From 1750 to 2019, 571 known plant species were extinct⁴. The number of extinct plants is more than that of extinct animals, affirming that the rate of plant extinctions is 500 times higher than before the Industrial Revolution.

Human industrialization has destroyed plant ecosystems through deforestation and climate change. We cut down trees, vegetation, and other forest ecosystems to make room for agricultural practices like crop farming and animal husbandry. We also destroy forests to use wood as fuel and natural resources to produce other materials. 

Our industrial activities also contribute to the fast rise in climate change and global warming, causing weather systems to fluctuate away from their natural state. Climate change leads to the depletion of nutrient sources for large populations of plants in nature, causing them to die. 

Extinction occurs rapidly because human activities isolate and reduce many plants. They lose access to nutrients and water and become susceptible to genetic drift and inbreeding, causing larger-scale problems like a decrease in seed viability, an increase in homozygosity, and a loss of genetic variation. 

It is even worse for rare plants that can only survive in a select location. You can revive some plants in small-scale site protection under the right conditions. However, it is different from many rare plants. The extinction of rare plants occurs because they;

• A particular soil or rock substrate type is required. 
• It requires specific mutual relationships with other organisms, like fungal partners and pollinators.
• They have gravity or ant-dispersed seeds that make growing in a fragmented habitat challenging because they can’t move far enough.      
• Also, introducing non-native organisms, pathogens, and pests causes extinction.

9 Extinct Plant Species  

Table of contents:

1. Helena Olive (Nesiota elliptica)

Saint Helena Olive became extinct in the wild in 1994⁸. It was a monotypic genus of flowering plants, Nesiota, in the family Rhamnaceae. Helena olive had stout branches with tiny pink flowers. It was native to a small volcanic island in the South Atlantic Ocean. 

It is not related to the true olive plant species, Olea europaea. The last remaining cultivation died in 2003 from fungal infection. Humans are responsible for the destruction of St. Helena trees. They cleared Helena's olive trees to create agricultural space, cut down trees for fuel, and built houses.

2. Cooksonia

Cooksonia is a genus of vascular extinct plants. In the 1970s, a student scientist named John Feehan found Cooksonia fossil plants on a mountainside close to Moneygall. The plants contain tissues that transport water, nutrients, and saps. 

Cooksonia existed about 415 million years ago, from the late Silurian to the late Devonian period⁶. These plants were the first to evolve from algae during the Carboniferous period. 

Cooksonia was a few centimeters tall and didn't have roots or leaves. Scientists have yet to determine its photosynthesis process. However, it became a land plant with its water-conducting stems. Cooksonia is easily recognizable because it looks like moss.

3. Araucarioxylon arizonicum

In Arizona's Petrified Forest National Park, you will find fossils of forest conifer trees. Among these fossils is Araucarioxylon arizonicum. It lived 225 years ago, during the late Triassic period. It grew up to 59 meters tall and had a trunk that was 3 meters thick³.

Most people refer to the extinct species as rainbow wood because of the various colors of its fossils. The yellow and red colors are from large iron oxide particles, while purple hues form from the distribution of fine hematite.

4. Sigillaria

Sigillaria is an extinct species of tree-sized lycopsids from the carboniferous period. This genus’s fossils were primarily found in Pennsylvania rocks. On rocks, it formed a hexagon-shaped circular pattern of leaf scars arranged vertically one above another. 

Upon further examination of the fossils of Sigillaria, researchers discovered it had scales instead of barks. They also found that it reproduced through spores. The more giant megaspore cells produced egg cells, while the smaller microspores produced sperm cells.

Before extinction, Sigillaria grew to 30 m tall and had a circumferential thickness of about 1 meter. Its thin trunks were a compact series that created the main trunk.

5. Calamites

Calamites are extinct plants that lived about 360 - 250 million years ago. Calamite fossils show² that the tree-like plant grew 20-30 meters high and looked identical to modern-day horsetail ferns. Its habitat was swampy forests that eventually became peat and coal. The extinct plants grew on unstable mud, silt, and sand.

They belong to a plant group called sphenopsids. They are reed-like plants with jointed stems. Botanists found the fossils in shales, siltstones, sandstones, and iron carbonate. The nodes of the plant have a saw-tooth pattern. Interestingly, they are the only plant from its period that can asexually reproduce, all thanks to their underground rhizomes.

6. Glossopteris

Next on our list is Glossopteris, a genus of woody seed ferns found on three continents. It became a species extinct in the wild 300 to 250 million years ago¹.

It is possible because Earth used to be a supercontinent called Gondwana. There are 70 recognized species in India, with additional plant species in Africa, Antantartica, Australia, and South America.

It is difficult to discuss its basic structures because the collected leaves and branches are poorly preserved. No one is sure of what the plant looked like. However, botanists are sure that the pollen and seeds from Glossopteris come from separate organs attached to different leaves. Some speculate the plant is a small tree or a large shrub.

7. Franklin Tree (Franklinia alatamaha)

Since 1803, researchers have not seen a Franklin tree in the wild⁷. Scientists have yet to discover the reason behind the extinction of this flowering tree in the wild, but many cultivations exist. Some botanists believe deforestation for cotton plantations caused the plant extinction. 

John Bartram and William Bartram discovered the Franklin tree along the banks of the Altamaha River in southeastern Georgia in 1765. That same year, King George III appointed John as the Royal Botanist for North America. William, John’s son, went back to collect the seeds of the Franklin tree to cultivate them in Bartam’s garden in Philadelphia.

This plant grew nowhere else in the wild except around the Altamaha River. It is a single-trunk tree with a multi-stemmed shrub. The Franklin tree grows between 10 and 20 feet tall and blooms with beautiful white, 5-petaled flowers in late summer to early fall. 

There's a yellow stamen at the center of the flowers. The leaves are long and narrow, with glossy dark green leaves. The leaves are often 5 inches long and change colors in autumn. They charge to different shades of red, orange, and purple. John Bartram named the plant after Benjamin Franklin, an American statesman, scientist, and philosopher.

8. Tulare Saltbush (Atriplex tularensis)

The last record of Tulare saltbush in the wild was in 1991. It is a reddish-green plant that grows annually. It reached 80 cm in height and had white, scaly stems and leaves. Its habitat was alkaline salt pans in the southern region of the California Central Valley. 

Its main extinction drivers are agriculture expansion and lowered water tables. Farmers drained inland lakes and deep water aquifers faster than mountain runoff could refill them, and the plant became extinct from water scarcity. 

9. Toromiro Tree (Sophora toromiro)

The Toromiro Tree’s natural habitat was on Rapa Nui, the Pacific island where it evolved. It is a reddish-brown tree with vertical fissures. The small gray-green leaves have tiny silky hairs on the underside. 

Toromiro grows up to 6 m long and spreads across 4 m. It also has yellow flowers that are 3 cm long, with long brown pods of fruit. The plant is extinct in its natural habitat because of the heavy deforestation in the first half of the 17th century.

The last wild toromiro was used as firewood in 1960⁵. Fortunately, a Norwegian Explorer, Thor Heyerdahl, collected the seeds and took them to Europe. The Royal Botanic Gardens, Kew, and the Gothenburg Botanical Garden in Sweden are trying to revive the plant in the native region, Rapa Nui.

Preventing Extinction: Conservation Efforts 

Some efforts being made to protect plant life include the creation of sanctuaries to help regrow extinct plants. Examples of these sanctuaries are seed banks and botanical gardens. Seed banks have a wide variety of herbarium specimens. They keep seeds to preserve nature's genetic diversity.  

On the other hand, botanical gardens help regrow old herbarium specimens and preserve species at risk of extinction. By protecting the land around us, we can also prevent plant extinction. We can stop unnecessary deforestation and other activities that cause global warming. 

Examples of organizations that contribute to the conservation of plants are: 

• Botanic Gardens Conservation International is the International Union of Botanic Gardens, with fellow members like the New York Botanical Garden worldwide. 
• Native Plant Network
• Defenders of Wildlife
• Millennium Seed Bank
• Svalbard Global Seed Vault

Conclusion    

The extinction of plants in the western United States is due to European settlement. The rapid rise of industrialization damaged the ecosystems of many species. Fortunately, the world is starting to realize the disadvantages of ecosystem extinctions. We will do everything in our power to prevent the extinction of other plants and wildlife habitats.