Extremophytes: Plants that Flourish in Extreme Conditions

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When you think about what a plant needs to survive, you imagine things like sunlight, fertile soil, water, and nutrients. But what happens when those things are scarce?

You could be fooled into thinking that a lack of these things would mean that plant life cannot survive. While many plants do indeed struggle under such circumstances, there exists a fascinating category known as extremophytes, which not only endure but actually thrive in the harshest conditions.

What are Extremophyte Plants?

Plants that are able to survive in extreme conditions are known as extremophytes. These hostile conditions could include extreme temperatures, high salinity, a lack of water, contaminants in the soil, and many other things.

While many plants wouldn’t make it a day in these conditions, extremophytes are specially adapted with unique root systems, unusual metabolism, and other features that allow them to live in such challenging environments. Some even have their very own antifreeze proteins!

Owing to the ability of some extremophytes to absorb usually harmful substances like chemicals and heavy metals, scientists sometimes use them to clean up pollution. Besides, extremophytes are important members of the ecosystem, providing biodiversity, acting as indicators, and even preventing soil erosion.

Examples of Extreme Plant Environments

Extremophytes live in all kinds of extreme environments, and no two are the same. From super hot deserts to the freezing Arctic tundra and acid filled soils to places where water is a rare luxury, these plants can be found all over the world.

1. Xeric Settings

Most people would describe a xeric setting as a hot desert and, for all intents and purposes, that’s what it is. It is officially described as a place with a lack of precipitation, low humidity, and dry conditions. Still, there are many plants that are specially adapted to living in this type of environment. 

What makes the environment so hostile for plants?

Plants that live in a xeric environment are exposed to a lot of sunlight and dry heat. What’s more, deserts are some of the windiest places on earth, and sandstorms can be abrasive and damaging to plants due to water loss. Where the sun is concerned, you might think that this would be a good thing (lots of photosynthesis) but for most plants, extreme and constant daylight can cause solar radiation which damages the cells and tissues. 

And let’s not forget all of that daytime heat which is then rapidly replaced by sometimes freezing temperatures at night. Such high temperatures mean faster evaporation, which can be extremely stressful and damaging to plants.

On top of this, xeric plants don’t have such ready access to water. You’ll probably be aware that plants need a lot of water to survive, but it’s simply so scarce here.

The soil in the desert is often not very nutrient rich, which means a lot of plant types wouldn’t be able to cope. Nutrients are essential for plants to grow and even when they do, without nutrients, their development is slowed. In addition to nutrient-low soil, the soil in xeric environments can contain a lot of substances that make it even more difficult for plants to access resources. This can include very high levels of minerals and salt.

As if all of that wasn’t enough, the limited resources in the xeric environment mean that plants need to compete. Only the toughest of the tough will thrive here.

Examples Of Xeric Locations

Xeric locations are desert ecosystems and are arid environments that receive very little rainfall and experience high temperatures.

The Sahara Desert in Northern Africa is probably one of the most well-known xeric locations on the planet as well as the Mojave Desert in North America. Another great example is the Nama Karoo Desert in South Africa, which is known to receive no more than 4-20 inches (100-500 mm) of precipitation each year. 

Adaptations

In order to survive in such harsh desert conditions, xeric plants need to be specially adapted. One of the most important adaptations is the ability to store water, which is most associated with cacti and succulents. Inside these plants are special structures designed to retain water, allowing some species to go without water for up to 2 years!

That said, there are some species that will appear to die, but what they’re really doing is entering a dormant state when water is scarce. A great example of this is the resurrection plant which looks dead but, when there is rainfall, it suddenly springs back to life. 

Evaporation can drastically affect the moisture within a plant, so xeric plants often have smaller leaves, which means a smaller surface for water to evaporate from. What’s more, their roots often run much more deeply which allows them to access groundwater. They’re also more likely to be low-growing in order to keep as far away from the sun and out of the wind as possible.

These types of plants often have specialized genes that are designed to withstand the conditions of drought that they’re often exposed to. These genes have likely evolved over time, as have other traits, such as the ability to use crassulacean acid metabolism (CAM) photosynthesis.

CAM photosynthesis involves the plant only opening its stomata (small openings in the leaves) at night, which reduces the risk of evaporation via transpiration. During this time, the plant is still able to take in carbon dioxide without the risk of losing water. In addition to this, the leaves are often covered in a wax-like coating or tiny hairs that further prevent water loss. The leaves may also have a reflective coating that causes sunlight to bounce off it, therefore preventing overheating.

On the flip side, there are some very cold xeric environments and, in this case, plants need to avoid freezing. Some species have special proteins that act as an antifreeze, preventing ice crystals from forming.

It’s all well and good surviving in arid conditions but in order to thrive, a plant needs to successfully reproduce. While high winds are great at transporting seeds, these plants have to do their bit too, and many produce highly-resistant seeds that can lie dormant and will only become viable when there is sufficient water availability. The same can be said about flowering which typically only happens in the right conditions.

2. Polar Regions

We’ve all got an image of the polar regions in our minds; cold, frozen conditions, darkness; none of it seems conducive to plant life. But that doesn’t stop more than 1000 plant species from thriving in these conditions.

What makes the environment so hostile for plants?

The most obvious harsh reality of the polar regions is the extremely cold temperatures. Average summer temperatures don’t often come above freezing in the North Pole and can be even lower in the South Pole, which means that some areas are permanently frozen, meaning that plant roots cannot access nutrients and drainage is poor. 

Even where the growing conditions are optimal, this doesn’t last for very long. In fact, on the Arctic Tundra, the growing season lasts a measly couple of weeks, meaning that the processes of growth and reproduction need to be drastically sped up. Waterlogging is a problem due to improper drainage and because of the frozen soil, nutrients are not readily available.

And it isn’t just the cold that’s a problem, the weather in general can be a serious threat to plant life with harsh winds that can cause severe dehydration because of rapid evaporation. What’s more, daylight in polar regions, especially in winter, is very scarce, which can affect the plants’ ability to photosynthesise.

As I mentioned, the soil in polar regions is often frozen, but there is a freeze-thaw cycle and this can wreak havoc with the soil stability, often resulting in heaving, which can damage plant roots. What’s more, when the soil is frozen, this can result in ice crystals forming in the plants’ cells which may damage, or even kill them.

Even where plants do survive in these extreme conditions, not much else does, and that includes pollinators. Pollination is essential for plant reproduction which can be very challenging in polar regions.

Examples of Polar Locations

The Arctic tundra is perhaps one of the most well-known polar regions and includes areas like Svalbard in Norway, the North Slope in Alaska, and the Taymyr Peninsula in Russia.

Moving to the South Pole, the Antarctic Peninsula suffers from the extreme conditions I discussed earlier.

Adaptations

Living in extremely cold temperatures requires the ability to withstand these conditions, so many polar plants are specially evolved to put up with drastically cold temperatures. What’s more, a lot of plants produce special proteins that act as an antifreeze, preventing ice crystals from forming in their cells that would otherwise cause potential damage or death.

Like the plants I talked about in xeric environments, polar plants are also often low growing which limits their exposure to the wind and cold, meaning they’re able to retain more heat. Another method of heat retention is the way that these plants grow in clusters. These clusters can trap heat and even create their own microclimate. Roots of these plants don’t grow deeply but remain much closer to the surface where the soil is most active. They’re also specially adapted to absorb nutrients more efficiently in soil that often doesn’t contain sufficient nutrients for plant life. If you look at polar plants, you may also notice that their leaves are quite unique, and this is because they’re specially adapted to keep surface area to a minimum. This can include rolled or crinkled leaves which aid in reducing evaporation or exposure to the sun and wind.

While you might think that the polar regions receive a lot of precipitation because of all the snow, this isn’t always true. In fact, these can be some of the driest areas on the planet, so many plants have evolved to be tolerant of dehydration and desiccation and may even remain inactive for up to nine months when conditions are poor.

When it comes to timing, there is nothing more important for polar plants. During the small window of opportunity, these plants must be able to reproduce in quick time. They’re adapted to have very short life cycles which allows for this since summer can last just a matter of weeks.  What’s more, these plants will delay their blooming period until the conditions are just right to ensure the most successful reproduction.

Polar plants don’t have as much access to sunlight as other species, so they’ve got unique photosynthesis abilities, including keeping their leaves year round, to maximize on the little sunlight that’s available in summer.

3. Acidic Soils

Acidic soil can seriously affect plant productivity and it’s a common problem for gardeners and farmers. While it is possible to alter the pH of soil for human use, this isn’t something that happens in nature but amazingly, some tough plants still survive. 

What makes the environment so hostile for plants?

When it comes to the pH level of soil, things have to be just right, but acidic soils have a very low pH and this can affect the plants’ ability to absorb nutrients. While they do need a certain amount of acidity, too much can cause the plant to struggle.

When this happens in the garden, you may notice the condition and health of plants deteriorating. This can include problems like root rot, yellow leaves, and poor growth, among other things. In wild environments, these same issues apply for many plants. What’s more, it is not uncommon for acidic soil to contain light levels of aluminum and other minerals like manganese, which can further affect plants’ ability to take up nutrients and affect its overall health.

Owing to this imbalance in the soil, plants may struggle to take root, which has a direct impact on their ability to grow healthily. Since acidic environments pose a serious challenge to plant life, not many species can grow in these conditions, resulting in poor biodiversity.

As well as being well balanced, soil also needs to have good structure which isn’t usually the case where the acidity levels are too high. That’s because the acidity levels may result in poorly aggregated particles which then results in insufficient drainage. These soils may not be able to hold onto moisture as well, which means less water for the plants.

We also have to consider the natural activity within the soil which, in acidic soils means a suppression of microbial activity. Without this, nutrient cycling is not as efficient. What’s more, the acidic environment can affect enzyme activity, which again affects the plants’ ability to absorb nutrients.

Examples of Acidic Environments

Acidic environments can be found all over the world in a variety of different climates. For example, they’re common in the Irish bogs and the Everglades in Florida where there are lots of peatlands. But they’re also just as common in heathlands in mountainous regions like the Alps and the Scottish Highlands.

The Scottish uplands also have a lot of acidic areas, as do other northern locations, such as the moorlands in Scandinavia and the Rocky Mountains in North America. Other North American examples of highly acidic environments include the Pine Barrens in New Jersey and the subalpine meadows of the Cascades.

Rocky areas in Appalachia have a lot of acidic soil, as do many coastal heathlands around the world.

Adaptations

In order to tolerate the extreme conditions, plants in acidic soils have adapted a set of traits that allow them to thrive. These traits include a special mechanism that makes the plant resistant to the high levels of aluminum found in acidic soils.

What’s more, soil is becoming more acidic in many locations due to the decay of organic matter, rainfall, and other factors but many plants are still able to absorb nutrients from the soil thanks to a more efficient method of uptake. This can include elongated roots or roots that branch out to access all available nutrients. This feature also benefits the plant in terms of water uptake.

Another way these plants make the most of the nutrients within the soil is to release acid themselves which breaks down minerals, creating new nutrients for them to absorb. Even more amazing is that some species are able to use a process known as cation ion exchange whereby the plant’s roots release hydrogen that can change the composition of the soil, making it less acidic.

Many plants (and animals) form symbiotic relationships where they work together for the benefit of both organisms. This is common with plants in acidic soil and usually happens with mycorrhizal fungi which give the plant’s roots greater reach and access to water and nutrients. 

4. Halophyte Areas

Imagine pouring salt into the soil of your favorite garden plants; it would cause no end of problems, including the plant’s ability to photosynthesise. But there are areas of the world that have very high salinity levels and yet, many plant species are able to survive here.  

What makes the environment so hostile for plants?

Most plants would struggle to survive in halophyte areas because of the extremely high levels of salinity. This could either be in the soil or in bodies of water that surround the location. Usually, plants would experience osmotic stress under these conditions as the salt removes much of the moisture from the plant cells. Naturally, this dehydrates the plant, but even the presence of salt can reduce the local availability of water. What’s more, chloride and sodium cause an imbalance within the cells, which ultimately leads to their damage.

As well as reducing local water availability, the presence of salt in the soil can cause an imbalance of the important nutrients that plants need. This can lead to effects on the plant’s overall growth and health and, in some cases, will result in its death. Not to mention that waves and wind can also spray more salt onto the plant, again affecting its health.

If you look at the soil in a halophyte area, you will see a marked difference to regular soil as a result of soil crusting. This happens because the salt accumulates in the soil making it harder which has a direct impact on drainage and aeration.

Examples of Halophyte Locations

It may surprise you to learn that saline environments are not limited to coastal areas, although they are common here, especially around mangroves. Some good examples of these areas include the Florida Everglades and the Sundarbans in South East Asia. Halophyte areas can also be found along sandy shorelines, such as the coastal dunes in Namibia. The Dead Sea is also surrounded by plant life that has adapted to these harsh conditions.

However, these areas can also be found inland, particularly in salt-rich lakes such as The Great Salt Lake and Lake Eyre in Australia. Saline deserts are also common around the world, some notable examples include the Chott el Jerid in Tunisia and the Dasht-e Kavir in Iran.

You’ll also find halophyte plants growing in salt pans such as the Salar de Uyuni in Bolivia, which is of particular interest owing to the sheer number of unique halophyte species.

Adaptations

Without their unique salt tolerance mechanisms, halophyte plants would never survive. There are plants that do not possess these traits that would simply die as a result of salt toxicity. But these amazing species are able to excrete salt through special glands on the leaves so that it doesn’t build up inside the plant. On the other hand, there are some species that actually store salt inside specially adapted cells so that it doesn’t affect or damage other cells. Examples include the tamarisk and the saltbush.

On top of this, many halophyte plants are succulents, meaning they can store water which is essential owing to a lack of moisture in these locations. This also helps to prevent osmotic stress. Going even further, there are some halophyte species that absorb high saline water from the soil but then process it so that the salt is diluted. Their roots are also specially adapted to be able to take up nutrients from the soil despite the presence of salt.

Just like plants in hot deserts, many halophyte plants use CAM photosynthesis. This helps to reduce the amount of water lost to transpiration, which is important owing to the low water availability in these locations. What’s more, these plants have the amazing ability to select which ions they absorb, such as potassium and nitrogen, while omitting the absorption of sodium. 

5. Alkaline Environments

While the pH of some soils makes it very acidic, on the other end of the scale, the pH is much higher resulting in a heavily alkaline soil. These areas are found all over the world, particularly in Africa and North America, but that doesn’t stop some plants from growing here.

What makes the environment so hostile for plants?

The main characteristic of alkaline soils is a high pH that is typically greater than 8.5. As with acidic soils, this is something that farmers and gardeners can counteract but in the wild, nature is left to fend for itself, and most plant species would not be able to survive.

Interestingly, these areas can result in mineral precipitation and this reduces the number of available nutrients within the soil. What’s more, any available nutrients may become deficient, so plants are not as easily able to absorb them. What nutrients remain, notably sodium and boron, can increase to toxic levels. Ions are also less accessible to plants and when this happens, they’re not as easily able to take up water and nutrients, therefore their health is affected.

Plant health and growth in areas like this can also be hindered because of the dense structure of the soil, making it difficult for roots to penetrate. This also makes the soil less able to hold onto water, meaning that plant life in these areas is often exposed to drought conditions and therefore, stress.

Examples of Alkaline Soil Locations

There is a surprising number of alkaline rich areas around the world, including Lake Natron in Tanzania and Lake Mono in North America; these are known as soda lakes because of their unnaturally high alkaline content.

Wetlands can also possess very alkaline soils, such as the Alkaline Fens in Europe and California’s Alkali Sink that covers a whopping 930 acres (376 hectares) and, despite its hostile conditions, is a protected area. 

You’ll also find these alkaline-loving plants in some desert basins where the soils have a high alkaline pH because of a build up of minerals. The Bonneville salt flats in Utah are just one example of this.

There are some alkaline soils that also have a very high salt content, making the conditions even more of a challenge. The Qadim Basin in China and the Sebkha Te-n-Dghamcha in Algeria are great examples of this. Moreover, there are some soils, like those found in the Burren in Ireland and the White Desert in Egypt, where there is also a high level of calcium.

Adaptations

In order to survive in such harsh conditions, plants have developed a number of alkaline tolerance mechanisms, such as root adaptations, that allow them to alter how they transport and process ions. This means they are able to survive with limited nutrients. Many plants may be affected by a reduced ability to uptake nutrients because of high levels of bicarbonate ions. But in these environments, plants have adapted ways of managing these ions, and some may even accept bicarbonate as an alternative source of carbon. 

Where calcium may be detrimental to the health of a lot of plant species, alkaline tolerant plants have adapted to use this substance to their benefit. In these cases, calcium can impact growth for the good although the plants are still efficiently adapted to absorb the usual nutrients like phosphorus and nitrogen, even though they’re not as readily available.

In order to absorb nutrients from the soil, these alkaline plants need to have efficient root systems. This can include branching roots or longer roots which allow them to maximize on the available water and nutrients within the soil. What’s more, since water may be scarce, alkaline plants are adapted to be drought tolerant, going for long periods without water.

Types of Extremophyte Plant Species

While not all conditions are ideal for most plants, there are many species that are especially adapted and can thrive in extreme conditions.

1. Resurrection Plant (Selaginella lepidophylla)

I mentioned the resurrection plant earlier in this guide, and it’s one of the most fascinating extremophytes on the planet. A fern-like species, the resurrection plant is found in the dry desert regions of Central America and the southwestern parts of North America; it’s fondly been dubbed the rose of Jericho.

Even during periods of extreme drought, this plant will battle through, thanks to its ability to seemingly rise from the dead. Completely desiccated, the resurrection plant will curl into a ball and may remain like this, without water, for up to 7 years! Still, thanks to its hydromorphic tissues, when water is applied, the plant can rehydrate in as little as a few hours.

But before the plant starts to curl up, it has a great protection mechanism in the form of a waxy coating over the leaves, which helps to reduce water loss and prevent cell damage. The plant is so effective in its survival strategies that it’s often used as an educational resource in how plants can revive after being dormant. There’s even suggestions that the plant could inspire technology and may even be able to help with vaccine preservation without the need for refrigeration. 

Owing to its special adaptations and the fact that this plant will release reproductive spores after rehydration, it’s able to survive in extreme and changing conditions.

2. Arctic Willow (Salix arctica)

The most northern woody plant on the planet, the Arctic willow grows on the tundra and in rocky areas where conditions are incredibly challenging. However, the species has special adaptations that allow it to endure these conditions, such as growing low to avoid exposure to the cold and wind which helps to keep the plant warm.

It has a fast growing nature which allows it to flourish during the short growing period. Rather than reproducing in the traditional way, Arctic willows form clones, which is a much faster process, and a plant can grow from a dormant bud or overcome damage and resprout. They’re also able to produce their own natural pesticide, so they aren’t affected by insects.

During the brief thaw in the Arctic, the Arctic willow takes advantage of the softer soil by penetrating deeply with its roots, allowing for better nutrient and water absorption. It can even root in permafrost! Additionally, the plant forms a symbiotic relationship with fungi which further boosts its ability to absorb important nutrients.

With such excellent resilience to the harsh conditions, it’ll come as no surprise that Arctic willows are of interest to science and research. Not only do they ensure good soil stability and nutrient cycling, but they’re also an indicator species that tell us a lot about the environment and ecosystem. So essential are they that they are protected and conserved. While there are many in the wild, this remains a vulnerable species because of the harsh conditions of its habitat.

3. Mangrove (Rhizophora spp.)

Mangroves are an important tree species as they’re known for their ability to sequester carbon, which can decrease the risk of sea levels rising in the areas that they are found. What’s more, they create stability within their environment as a natural barrier against erosion. These trees are highly tolerant of saline conditions and are found in tropical and subtropical coastal areas like estuaries.

Not only are mangrove able to survive in saline soils, but they’re also tolerant of waterlogged soil. Emerging roots from the trunk ensure stability in these unstable soils, but these also help the plant to breathe; including oxygen.

They possess special glands known as cytological molecular pumps that help them to excrete salt. What’s more, when they absorb nutrients, these trees are able to exclude salt and only absorb the good stuff! Wax coated leaves also prevent soil from getting into the plant at the same time as helping to retain moisture.

Mangrove trees are not only useful in protecting the physical environment, but they are also the perfect habitat for marine and wildlife. What’s more, humans have put them to good use in various ways, such as in traditional medicine and for their wood which has a high strength to weight ratio.

4. Glasswort (Salicornia spp.)

Glasswort is probably more commonly known as samphire and belongs to the Salicornia genus of salt-tolerant succulents. These plants grow in high saline environments such as coastal areas and salt flats and are classified as extremophytes due to being able to grow in not only salty locations but also waterlogged soils.

While some plants are able to excrete salt, glasswort has special salt bladders that allow it to store excess salt. What’s more, being succulents, their thick leaves enable them to store water. These plants also have the ability to regulate their water content so they don’t lose moisture to transpiration and can even exclude certain ions from being absorbed.

As well as having some incredible physiological adaptations, glasswort is also of the utmost ecological importance. For example, this species provides habitat for wildlife but is also used as a food source for humans, particularly in seafood dishes to which it adds a bright, citrusy flavor.

These plants, being edible, could be a viable crop in saline locations where other crops cannot be grown. They’re also commonly used in traditional medicine and are highly adaptable. If they can be used in agriculture, they’ll not only create a viable income for farmers but also benefit the land since they help to prevent soil erosion. This not only benefits the environment but also creates suitable habitat for other species.

5. Madagascar Ocotillo (Alluaudia procera)

Sadly Madagascar ocotillo is listed as vulnerable on the IUCN Red List so conservation of the plant is essential. Deforestation seems to be the main cause of the decline of this tough species.

However, the plant still thrives on its native island of Madagascar and is found growing in desert conditions where it relies on several adaptations for its survival. This includes thick stems, being succulent, that store water allowing the plant to survive drought. What’s more, the Madagascar ocotillo uses its stems for photosynthesis, reducing the need for large leaves, which helps the plant retain water. Those stems are also used to reduce exposure to sunlight, ensuring the plant doesn’t overheat.

Not only is this plant an important member of the Madagascan flora, it’s also valued by humans who use it in traditional medicine. It’s also essential for local wildlife that use it for food, such as lemurs.

6. Saltbush (Atriplex spp.)

I talked about the saltbush earlier in this guide and mentioned that this species, from the Amanrantheceae family, is able to store salt within its cells. However, this isn’t true of all saltbush species, and some will excrete salt through special glands. In any case, these extremophytes are able to thrive in high salinity conditions and arid areas.

Living in dry conditions, saltbushes have to use water wisely, and they do this with their ability to absorb water from salty soils. Not something that all plants can do! They also have specially adapted leaves with a reduced surface area to avoid losing moisture to transpiration.

In areas where the salt content of the soil is high, agriculture is still possible thanks to the saltbush which is often used by farmers to feed livestock. Moreover, these plants help to prevent soil erosion, making it healthier than it would otherwise be.

In the wild, the saltbush provides a food source for various animals, including jack rabbits and porcupine as well as attracting pollinators like bees. This means improved biodiversity in the location. 

7. Sphagnum Moss (Sphagnum spp.)

Sometimes called peat moss owing to the fact that it grows in marshes, bogs, and peatlands, sphagnum moss is a name used to describe more than 380 species. Growing in a carpet-like fashion, sphagnum moss is able to thrive in acidic, waterlogged environments where other plants would struggle. This is partially because it is able to retain a lot of water, and its specialized capillaries allow water to be moved around the plant against the force of gravity. Being able to hold onto a lot of water also means that this plant has the power to prevent flooding.

When this moss absorbs water, it also extracts nutrients from it, feeding itself in a very unique way. What’s more, it doesn’t have to compete for resources as sphagnum moss releases acid, making the environment even less suitable for other plant species. It is this very action that causes peat formation since the high acid levels mean that organic matter doesn’t decompose as rapidly. Still, there are many organisms like bell heather, golden plovers, and hen harriers that thrive in this type of environment, so peat moss is essential in maintaining this habitat.

What’s more, peat moss holds a lot of carbon, which is essential in mitigating the effects of climate change. Humans have long used sphagnum moss in gardening, wound treatment, and even as tinder for starting a fire. 

8. Mojave Desert Joshua Tree (Yucca brevifolia)

The Joshua tree, named after the biblical character of the same name, is a species of yucca found in the Mojave Desert. It has a very unique appearance and can grow to around 49 feet (15 meters) in height. But what’s interesting is its broad canopy and root system, which allow it greater access to water. What’s more, the leaves are thick and fleshy, allowing the tree to store water. Not only does this mean they can go without water for long periods, but it also contributes to their long lifespan; there is one tree in California that’s thought to be around 1000 years old!

The leaves are small to avoid transpiration-related water loss and the Joshua tree only blooms at night to reduce the risk of evaporation. With its widely spread branches, this tree is able to get maximum sunlight exposure for effective photosynthesis.

The Joshua tree creates habitat for various wildlife but most notably, it has a symbiotic relationship with the yucca moth which is its only pollinator. What does the moth get from this? It lays its eggs in the flowers and its young can feed on the seeds.

While scientists do favor the Joshua tree for research on how ecosystems respond to climate change, it is noted that this tree could become endangered because of habitat loss. If given this status, the species will then be protected in certain areas.

9. Heather (Calluna vulgaris, Erica spp.)

Native to Europe and Minor Asia, heather is a collection of species belonging to the families Calluna vulgaris and Erica genera. They’re typically found in heathlands or bogs, where there may be highly acidic or even waterlogged soils. They may also grow in pine or oak woodlands

The reason that heather is able to thrive in acidic soil is because it has specially adapted tissues that make it more resistant to its environment. And these plants are essential in their ecosystems, providing habitat for small animals and birds.

On top of this, heather is a very drought-resistant plant that’s capable of storing water in its leaves. Despite the fact that there may be low levels of nutrients within the soil, heather forms a relationship with mycorrhizal fungi, which allow the plant to extend its roots and absorb as many nutrients as possible. Even so, the plant doesn’t require anywhere near as many nutrients as other species.

Heather can also be very resistant to fire, even reproducing after a blaze. In fact, it’s common practice in Scotland for farmers to burn heather and after this, new shoots will appear or new seeds will be generated. Because of their hardy nature, heather is a popular plant species for gardeners.

10. Rock Saxifrage (Saxifraga spp.)

In alpine and rocky environments, we find 465 species that belong to the Saxifraga genus. Rock saxifrage is typically found at high elevations of up to 3,280 feet (1,000 meters) and is perfectly adapted to cope with rocky habitats.

These species grow in rock crevices and have strong roots that allow them to anchor to the harsh surfaces. Up here, things can get pretty chilly, but rock saxifrage is very tolerant to cold temperatures and can even withstand frost. While these plants are very slow growing, they have excellent longevity and are able to self-pollinate. That said, while it doesn’t require insect pollinators, the species does provide habitat for many insects and acts as a food source for local wildlife.

The nutrient content of the soil in these locations is usually very poor but this plant has, like many other species, formed a symbiotic relationship with fungi which expands its root reach and allows it to capture more nutrients. In terms of water, this can be scarce in these environments, but some species of Saxifraga are able to retain water to sustain them during dry periods.

Rock saxifrage produces pretty little flowers which are of particular interest to gardeners. What’s more, since the plant is very hardy and able to adapt to tough conditions, it’s a great choice as an ornamental plant.

11. Alpine Forget-Me-Not (Myosotis alpestris)

Native to Alpine and Subalpine regions, the Alpine forget-me-not is a highly adapted plant suited to high elevations up to 14,108 feet (4,300 meters)! Things at this height can get very challenging especially in terms of temperature, but these plants tend to grow in clusters to retain heat. They also grow low to the ground in order to reduce exposure.

Amazingly, the Alpine forget-me-not is very resistant to freezing temperatures, and despite the low nutrient availability at such high elevations, these plants have adapted well. As I mentioned, this species tends to grow low to the ground, and this also helps it to retain water in conditions where there may be as little as 12 inches (30 cm) of rainfall each year. 

The growing season within Alpine regions may be anywhere between 6 and 12 weeks, which is comparably short. However, these plants bloom very early to maximize seed production and pollination. Where pollination is concerned, the Alpine forget-me-not largely relies on insects, but it’s essential that they continue to thrive as they’re an important contributor to biodiversity. 

12. Halodule Seagrass (Halodule spp.)

As you may guess from the name, seagrass is found growing in a marine environment. While there are around 60 species, seagrass is the only type of flowering marine plant in the world. They grow in shallow water around the coastline and are essential for both humans and marine life. For example, while their roots stabilize the seafloor, their leaves provide shelter and food for a range of creatures. Humans rely on seagrass to support fisheries but sadly, the species is under threat due to coastal development that results in habitat loss. As many as 67 seagrass species are thought to be under threat because of humans.

Despite this, seagrass is an extremophyte that is classed as such because of its ability to survive in high salinity environments. The plant has thin leaves which are extremely flexible and therefore not affected by the waves or flow of the water. They have deep roots that allow them a strong anchor as well as allowing them to absorb nutrients from the sediment. What’s more, these deep roots create stability and prevent erosion.

The ocean is a huge carbon sink, and seagrass plays a vital role in this, sequestering carbon and having a direct impact on the mitigation of the effects of climate change. What’s more, it’s an important plant for nutrient cycling and since it’s so essential, there are many efforts to restore seagrass habitat in order that it will continue to provide benefits to both humans and wildlife.

13. Cushion Plant (Azorella spp.)

Cushion plants come in a variety of species belonging to the Azorella genus. What’s amazing about these plants is not only their ability to survive in alpine and arctic conditions but also their longevity. While it’s not uncommon for them to live for up to 850 years, there are records of some cushion plants living for 3000 years!

Wide spreading, cushion plants can grow outwards up to 5.9 feet (1.8 meters) and have great density, which allows them to retain heat. What’s more, these plants are very slow growing, and their spread also protects them from harsh winds and low temperatures.

In their Alpine and Arctic habitats, nutrient poor soils are common, but cushion plants have adapted to this, and they’re also very tolerant to dry conditions owing to their ability to store water because of their density.

Cushion plants aren’t just amazing, they’re also important because their dense growth creates a microclimate within the plant, which is ideal habitat for a range of insects, plants, and other organisms. Without cushion plants, there may not be as much biodiversity in these regions.

14. Yellow Horned Poppy (Glaucium flavum)

Yellow horn poppies are found in coastal regions in North Africa and Europe and are extremophytes because of their tolerance of high salinity environments. In order to thrive in such challenging conditions, the yellow horned poppy has a variety of adaptations, including the ability to excrete salt. They also have waxy leaves that are covered in hairs, which protect the plant from salt spray.

The roots of the yellow horned poppy are incredibly strong and allow it to remain stable even in loose, sandy soil. Because of this root system, these plants also contribute to erosion prevention in their habitats, which results in them shaping the very environment. However, it is worth noting that this plant is considered to be invasive in some areas because of its ability to quickly take over.

The yellow horned poppy blooms between June and September and produces brightly colored yellow flowers in order to attract pollinators. 

15. Mormon Tea (Ephedra spp.)

Mormon tea is found in arid and semi-arid regions in the western United States. Not only is it able to thrive in dry conditions, but is also specially adapted to cope with high temperatures and lots of sunlight.

For example, the leaves of the plant are very small and there are some species that don’t have leaves at all, which prevents water loss through transpiration. In this case, it’s the stem that performs photosynthesis, allowing the plant to gain energy without losing moisture. Within the tissues of the plant, water is stored, which means it can last through long periods of drought.

In some cases, the plant will only grow when there is sufficient moisture, and only the seeds will continue thriving during dry spells. These seeds are dispersed by the wind to ensure as high success rates as possible, which is why the plant is widespread over the dry landscape. 

In its habitat, Mormon tea must cope with high pH soils, and it has adapted to be able to tolerate high alkaline levels.

16. Welwitschia (Welwitschia mirabilis)

Welwitschia is primarily found in the Namib Desert, as well as in some parts of the Angolan Desert. It has adaptations that allow it to cope with extreme changes in temperature, dry conditions, and intense sunlight. What’s fascinating about this plant is its ability to thrive in such a challenging environment while having an exceptionally long lifespan. Some individual Welwitschia plants can live for hundreds of years, and in some cases, they can survive for up to 1500 years. This longevity explains why Welwitschia is a slow-growing plant.

This plant has a very unique appearance, with leaves that look like seaweed and large red cones, each of which house a single seed. It’s often called an ugly plant and, over time, the leaves become tangled, giving it an even more unusual appearance.

Still, it’s able to survive in such harsh conditions thanks to the leaves’ ability to retain water collected from dew and fog. The leaves send the water down into the soil and are unlikely to lose much via transportation owing to the fact that there are only two leaves per plant, and they’re split into ribbon-like sections.

Welwitschia is also very tolerant of high temperatures which are common during the day. At night, the temperature can drop significantly but again, this plant has adapted to cope with this. Since there isn’t a lot of water in the desert, the long taproots allows welwitschia to search for water under the ground as well as making the plant stable. The root system also ensures the plant can absorb enough nutrients from the often poor soil.

17. Barrel Cactus (Ferocactus spp.)

In deserts where there is very little rainfall and extreme temperatures, the barrel cactus seems to thrive. Its part of the Ferocactus genus, in which there are several different species, but they’re all found in the arid regions of Central and North America.

Like many cactus species, the barrel cactus is able to store water in its stem and also has a very thick skin, coated with wax that prevents it from losing moisture, especially considering it is exposed to intense sun for much of the day.

However, while it is able to resist these high temperatures, the barrel cactus is also exposed to low night time temperatures, for which it is just as readily adapted. What’s more, it has a root system that spreads much wider than it does deep, which means it can absorb as much water as possible during the rare occurrence of rain.

In the desert, the quality of the soil is pretty bad, but the barrel cactus is able to put up with this since it has the ability to conserve energy and nutrients within its tissues. While they are slow growing, some of these plants can live for an extremely long time, up to a century in some cases. 

The barrel cactus is important in its environment as it provides habitat and a food source for a range of creatures. Even humans have been known to eat it, and use it in traditional medicines.

18. Small Rockcress (Schrenkiella parvula)

Small rockcress is not only interesting because of its extremophyte classification but also because scientists believe that its special adaptations may be able to help develop more resilient crops able to grow in harsher soils and resist the effects of climate change. Researchers are able to use this plant to better understand how plants respond to stress. Plus, it’s even related to the oilseed plants we use to make bio-oil fuels.

Known scientifically as Schrenkiella parvula, this species is an herbaceous annual plant that is native to Central Asia. This flowering plant grows in a rosette and has small leaves, intended to reduce the surface area, making it less susceptible to water loss. This is essential since the species is known to grow in very arid conditions and therefore also has thicker leaves that can store water.

On top of this, small rockcress has very deep growing roots that give it access to ground water even when there isn’t much rainfall. The plant has a short life cycle, allowing it to reproduce before the conditions become too dry. What’s more, since it has a wide seed dispersal, the plant has a greater chance of reproducing.

As well as being tolerant of dry conditions, small rockcress is also able to grow in saline environments, so it’s classed as a halophyte. These plants have a special ability to process and regulate saline levels within the tissues, making it resistant to the otherwise toxic effects.