The Ancient Green Blobs of the Andes

February 3, 2021

Photo by Atlas of Wonders licensed under CC BY-NC-ND 2.0

Curious images of these strange green mounds make the rounds of social media every so often. What kind of alien life form is this? Is it a moss? Is it a fungus? The answer may surprise you!

These large, green mounds are comprised of a colony of plants in the carrot family! The Yareta, or Azorella compacta, hails from the Andes and only grows between 3,200 and 4,500 meters (10,500 - 14,750 ft) in elevation. Its tightly compacted growth habit is an adaptation to its high elevation lifestyle. Cushion growth like this helps these plants prevent heat and water loss in these cold, dry, windy environments.

Every so often, these mats erupt with tiny flowers, which must be a sight to behold! Photo by Lon&Queta licensed under CC BY-NC-SA 2.0

As you might imagine, these plants are extremely slow growers. By studying their growth rates over time, experts estimate that individual colonies expand at the rate of roughly 1.5 cm each year. By extrapolating these rates to the measurements of large colonies, we get a remarkable picture of how old some of these plants truly are. Indeed, some of the largest colonies are estimated at over 3000 years old, making them some of the oldest living organisms on the planet!

Sadly, the dense growth of the plant makes it highly sought after as a fuel source. Massive chunks of these plants are harvested with pick axes and burned as a source of heat. Due to their slow growth rate, overharvesting in recent years has caused a serious decline in Yareta populations. Local governments have since enacted laws to protect this species in hopes that it will give colonies the time they need to recover. Indeed, some recovery has already been documented, however, continued monitoring and management will be needed to ensure their populations remain viable into the foreseeable future.

Photo Credits: [1] [2]

Further Reading: [1] [2] [3]

Fraser Fir: A New Look at an Old Friend

January 13, 2021

Photo by James St. John licensed under CC BY 2.0

Growing up, Fraser fir (Abies fraseri) was a fairly common sight in our house. Each winter this species would usually win out over other options as the preferred tree for our living room during the holiday season. Indeed, its pleasing shape, lovely color, and soft needles have made it one of the most popular Christmas trees around the world. Amazingly, despite its popularity as a decoration, Fraser fir is so rare in the wild that it is considered an endangered species.

Fraser fir is native to only a handful of areas in the southern Appalachian Mountains. Together with red spruce (Picea rubens), this conifer makes up one of the rarest ecosystems on the continent - the southern Appalachian spruce-fir forest. Such forests only exist at elevations above 4,000 ft (1,200 m) from southwestern Virginia to western North Carolina and eastern Tennessee. The reason for this limited distribution is rooted in both modern day climate and North America’s glacial past.

Whereas anyone hiking through Appalachian spruce-fir forests could readily draw similarities to boreal forests found farther north, the Appalachian spruce-fir forests are nonetheless unique, hosting many species found nowhere else in the world. Indeed, these forests are holdovers from the Pleistocene when the southeast was much cooler than it is today. As glaciers retreated and the climate warmed, Appalachian spruce-fir forests “retreated” up the mountains, following their preferred climate zones until they hit the peaks of mountains and couldn’t go any further.

Indeed, Fraser fir is in large part limited in its distribution by temperature. This conifer does not perform well at high temperatures and is readily out-competed by other species under warmer conditions. Another factor that has maintained Appalachian spruce-fir forests at elevation is fog. The southern Appalachian Mountains host eastern North America’s only temperate rainforest and fog commonly blankets high elevation areas throughout the year. Research has shown that in addition to keeping these areas cool, fog also serves as an important source of water for Fraser fir and its neighbors. As fog condenses on its needles, these trees are able to absorb that water, keeping them hydrated even when rain is absent.

A view of an Appalachian spruce-fir forest from the Blue Ridge Parkway.

Due to its restricted habitat, Fraser fir has never been extremely common. However, things got even worse as Europeans colonized North America. Over the past two centuries, unsustainable logging and grazing practices have decimated southern Appalachian spruce-fir forests, fragmenting them into even smaller patches with no connectivity in between. In areas where thin, rocky soils were not completely washed away, Fraser fir seedlings did return, however, this was not always the case. In areas where soils were were lost, southern Appalachian spruce–fir forests were incapable of regenerating.

If the story ended there, Fraser fir and its habitat would still be in trouble but sadly, things only got worse with the introduction of the invasive balsam woolly adelgid (Adelges piceae) from Europe around 1900. Like the hemlock woolly adlegid, this invasive, sap-feeding insect has decimated Fraser fir populations throughout southern Appalachia. Having shared no evolutionary history with the adelgid, Fraser fir is essentially defenseless and estimates suggest that upwards of 90% of infect trees have been killed by the invasion. Although plenty of Fraser fir seedlings have sprung up in the wake of this destruction, experts fear that as soon as those trees grow large enough to start forming fissures in their bark, the balsam woolly adelgid will once again experience a massive population boom and repeat the process of destruction again.

Dead Fraser fir as seen from Clingman’s Dome. Photo by Brian Stansberry licensed under CC BY 3.0

The loss of Fraser fir from this imperiled ecosystem has had a ripple effect. Fraser fir is much sturdier than its red spruce neighbors and thus provides an important windbreak, protecting other trees from the powerful gusts that sweep over the mountain tops on a regular basis. With a decline in the Fraser fir canopy, red spruce and other trees are more susceptible to blowdowns. Also, the dense, evergreen canopy of these Appalachian spruce-fir forests produces a unique microclimate that fosters the growth of myriad mosses, liverworts, ferns, and herbs that in turn support species like the endangered endemic spruce-fir moss spider (Microhexura montivaga). As Fraser fir is lost from these areas, the species that it once supported decline as well, placing the whole ecosystem at risk of collapse.

The moss-dominated understory of an Appalachian spruce-fir forest supports species found nowhere else in the world. Photo by Miguel.v licensed under CC BY 3.0

Luckily, the plight of this tree and the habitat it supports has not gone unnoticed by conservationists. Numerous groups and agencies are working on conserving and restoring Fraser fir and southern Appalachian spruce-fir forests to at least a portion of their former glory. This is not an easy task by any means. Aside from lack of funding and human power, southern Appalachian spruce-fir forest conservation and restoration is hindered by the ever present threat of a changing climate. Fears that the life-giving fog that supports this ecosystem may be changing make it difficult to prioritize areas suitable for reforestation. Also, the continued threat from invasive species like the balsam woolly adelgid can hamper even the best restoration and conservation efforts. Still, this doesn’t mean we must give up hope. With continued collaboration and effort, we can still ensure that this unique ecosystem has a chance to persist.

Please visit the Central Appalachian Spruce Restoration Initiative (CASRI) website to learn more!

Photo Credits: [1] [2] [4] [5]

Further Reading: [1] [2] [3] [4]

Himalayan snowball plants and their fashionably functional coats

November 25, 2019

Hairy plants are both fun and functional. Hairs or trichomes on the leaves of plants can serve a variety of functions. If the plant is growing in a region prone to cold temperatures, it is thought that a dense layer of hairs can function like a wool coat, keeping the plant warm when temperatures drop. This is such a popular idea that it is often assumed rather than tested. For a strange group commonly referred to as Himalayan snowball plants, the truth is a bit more complicated.

Himalayan snowball plants are members of the genus Saussurea, which hails from the family Asteraceae. Though the genus is widespread, the Himalayan snowball plants are confined to high elevation, alpine habitats in central Asia. As you can imagine, life at such altitudes is defined by extremes. Temperatures during the day can skyrocket due to the lack of atmospheric insulation. Conversely, temperatures can take a dive as weather changes and/or the sun goes down. One look at the Himalayan snowball plants tells you that these plants are wonderfully adapted to such habitats. But what kind of advantages does that this coat of hair provide?

Well, research has revealed a bit more nuance to the whole “winter coat” idea. Indeed, it does appear that the furry coat does in fact provide some insulation to the plant. However, most of the warmth appears to come from the dark color of the inflorescence rather than by pure insulation alone. After all, the vast majority of plants do not produce any heat. The flower heads or capitula of these daisy relatives is low in stature. This keeps it out of the way of the coldest winds. Also, they are so deeply violet in color that they can appear black. This is no accident. As anyone can tell you, darker colors absorb more heat and that is exactly what happens with the Himalayan snowball plants.

Another interesting thing to consider is that most of the growth and reproduction in these plants occurs during frost-free periods of the year. Though temperature swings are frequent, it rarely gets cold enough to severely damage plant tissues until long after the plants have flowered and set seed. Moreover, there is some evidence to suggest that the dense coat of hairs may have a cooling effect during periods of intense exposure to sunlight. Their light color may reflect a lot of the incoming radiation, sparing the plant from overheating. Therefore, it appears that the benefit of such a thick coat of hairs has more to do with avoiding temperature swings than it does ensuring constant warmth. By buffering the plant against huge swings in ambient temperature, the hairs are able to maintain more favorable conditions for plant growth and reproduction.

Also, because this area experiences a monsoon season during growth and flowering of Himalayan snowball plants, these hairs may also serve to repel water, keeping the plants from becoming completely saturated. If water were to stick around for too long, it could open the plant up to pathogens like fungi and bacteria. It could also be that by insulating the plant against temperature swings, the hairs also provide a more favorable microclimate for pollinators. Bumblebees are thought to be the main pollinators of Himalayan snowball plants and despite their ability to maintain higher internal temperatures relative to their surroundings, anything that can buffer them as they feed would be beneficial to both the bees and whatever plant they may be pollinating as a result.

Photo Credit: [1]

A New Case of Lizard Pollination from South Africa

April 22, 2019

With its compact growth habit and small, inconspicuous flowers tucked under its leaves, it seems like Guthriea capensis doesn’t want to be noticed. Indeed, it has earned itself the common name of '“hidden flower.” That’s not to say this plant is unsuccessful. In fact, it seems to do just fine tucked in among high-elevation rock crevices of its home range along the Drakensberg escarpment of South Africa. Despite its cryptic nature, something must be pollinating these plants and recent research has finally figured that out. It appears that the hidden flower has a friend in some local reptiles.

Lizard pollination is not unheard of ([1] & [2]), however, it is by no means a common pollination syndrome. This could have something to do with the fact that we haven’t been looking. Pollination studies are notoriously tricky. Just because something visits a flower does not mean its an effective pollinator. To investigate this properly, one needs ample hours of close observation and some manipulative experiments to get to the bottom of it. Before we get to that, however, its worth getting to know this strange plant in a little more detail.

The hidden flower is a member of an obscure family called Achariaceae. Though a few members have managed to catch our attention economically, most genera are poorly studied. The hidden flower itself appears to be adapted to high elevation environments, hence its compact growth form. By hugging the substrate, this little herb is able to avoid the punishing winds that characterize montane habitats. Plants are dioecious meaning individuals produce either male or female flowers, never both. The most interesting aspect of its flowers, however, are how inconspicuous they are.

The hidden flower (Guthriea capensis) in situ. — The hidden flower (*Guthriea capensis*) *in situ*.

Flowers are produced at the base of the plant, out of site from most organisms. They are small and mostly green in color except for the presence of a few bright orange glands near the base of the style, deep within the floral tube. What they lack in visibility, they make up for in nectar and smell. Each flower produced copious amounts of sticky, sugar-rich nectar. They are also scented. Taken together, these traits usually signal a pollination syndrome with tiny rodents but this assumption appears to be wrong.

Based on hours of video footage and a handful of clever experiments, a team of researchers from the University of KwaZulu-Natal and the University of the Free State have been able to demonstrate that lizards, not mammals, birds, or insects are the main pollinators of this cryptic plant. Two species of lizard native to this region, Pseudocordylus melanotus and Tropidosaura gularis, were the main floral visitors over the duration of the study period.

Tropidosaura gularis photo © 2009 Serban Proches licensed under CC BY-SA 2.5 — *Tropidosaura gularis* photo © 2009 Serban Proches licensed under CC BY-SA 2.5

Visiting lizards would spend time lapping up nectar from several flowers before moving off and in doing so, picked up lots of pollen in the process. Being covered in scales means that pollen can have a difficult time sticking to the face of a reptile but the researchers believe that this is where the sticky pollen comes into play. It is clear that the pollen adheres to the lizards’ face thanks to the fact that they are usually covered in sticky nectar. By examining repeated feeding attempts on different flowers, they also observed that not only do the lizards pick up plenty of pollen, they deposit it in just the right spot on the stigma for pollination to be successful. Insect visitors, on the other hand, were not as effective at proper pollen transfer.

Conspicuously absent from the visitation roster were rodents. The reason for this could lie in some of the compounds produced within the nectar. The team found high levels of a chemical called safranal, which is responsible for the smell of the flowers. Safranal is also bitter to the taste and it could very well serve as a deterrent to rodents and shrews. More work will be needed to confirm this hypothesis. Whatever the case, safranal does not seem to deter lizards and may even be the initial cue that lures them to the plant in the first place. Tongue flicking was observed in visiting lizards, which is often associated with finding food in other reptiles.

Male flower (a) and female flower (b). Note the presence of the orange glands at the base.

Another interesting observation is that the color of the floral tube and the orange glands within appear to match the colors of one of the lizard pollinators (Pseudocordylus subviridis ). Is it possible that this is further entices the lizards to visit the flowers? Other reptile pollination systems have demonstrated that lizards appear to respond well to color patterns for which they already have some sort of sensory bias. Is it possible that these flowers evolved in response to such a bias? Again, more work will be needed to say for sure.

By excluding vertebrates from visiting the flowers, the team was able to show that indeed lizards appear to be the main pollinators of these plants. Without pollen transfer, seed set is reduced by 95% wheres the additional exclusion of insects only reduced reproductive success by a further 4%. Taken together, it is clear that lizards are the main pollinators of the enigmatic hidden flower. This discovery expands on our limited knowledge of lizard pollination syndromes and rises many interesting questions about how such relationships evolve.

Photo Credit: [1] [2] [3]

The Smallest Clematis

December 19, 2018

Photo by Ghislain118 (AD) http://www.fleurs-des-montagnes.net licensed under CC BY-SA 3.0

At first glance, the marble clematis (Clematis marmoraria) looks more like an anemone than it does a clematis. You would be forgiven by most for the mistaken ID because it is one of only a handful of the roughly 300 described species that do not exhibit a vining growth form. Also, they hail from the same family - Ranunculaceae. The marble clematis is odd in that it lives its life as a compact “shrub” that hugs the rocks of its alpine habitat. And compact it is! The marble clematis is the smallest in the genus.

The marble clematis exhibits a very limited distribution. It can only be found growing wild in the alpine zone of two sites within Kahurangi National Park in New Zealand. It has only been known to science for a relatively short period of time, having been discovered in 1975. Subsequent investigations have been able to elucidate that its restricted to specific rocky substrates, mainly marble, hence both its common name and specific epithet were given to reflect that.

Like many members of the genus, the marble clematis is dioecious, meaning individual plants are either male or female. Flowering begins in December, as the southern hemisphere summer kicks into high gear. Being restricted to an alpine habitat means that this species has to pack growth and reproduction into only a few short weeks before nasty weather returns and buries it under snow. Despite its herbaceous appearance, the marble clematis is more accurately described as a sub-shrub as it attains a rather woody habit as it matures.

Other than its size, the fact that it is not a vine may be the most striking feature of the marble clematis. It is likely that natural selection simply doesn’t favor vine-like growth in such rocky terrain. There really isn’t a whole lot of neighboring vegetation to climb on and compete with so why both with an ambling habit? Also, its alpine environment doesn’t lend well to tall growth. Anything that scrambles up and over rocks is likely to be damaged by wind, sun, and freezing temperatures. As such, the marble clematis is more at home tucked into nooks and crannies than it is vining all over the place.

Unfortunately, its small size, slow growth rate, and limited distribution seem to be working against the marble clematis in our human-dominated world. Not only does climate change threaten its alpine habitat, human activity coupled with grazing by introduced goats and deer have seen populations of this unique species decline at an alarming rate. In 2009 the marble clematis was afforded ‘threatened’ status and is now considered Nationally Vulnerable by the New Zealand government. However, there is a silver lining to all of this and it lies in the hands of alpine garden enthusiasts.

It turns out, the marble clematis is fairly easy to grow. Together with its compact form and showy flowers, it has gained a lot of popularity among horticulturists and gardeners that enjoy rock gardening. Plants can easily be started by seeds or cuttings and, provided some basic soil needs are met (plenty of drainage), potted individuals can live long, healthy lives. Having plants in cultivation like this means that the risk of complete extinction is greatly minimized. Of course, ex situ collections are not a substitute for habitat conservation but it certainly helps mitigate at least some of the risks facing species like the marble clematis.

Photo Credits: [1] [2]

Further Reading: [1] [2] [3]

Meet Jones' Columbine

July 5, 2017

Photo by Steve licensed under CC BY-NC-SA 2.0

Meet Aquilegia jonesii. This interesting little columbine can be found growing in a narrow range along the northern Rockies. It only grows in alpine and sub-alpine zones, making it quite rare. It has a cushion-like growth form to shield it from the elements but disproportionately large flowers. It is a lucky day if one stumbles across this species!

Fun Fact: Both the common name and generic name of the flowers referred to collectively as "columbines" have their origins in ornithology?

That's right, the genus to which they belong, Aquilegia, can trace its origin to the word "aquila," which is Latin for "eagle." When the genus was being described, it was felt that the flower resembled the claw of an eagle.

The word "columbine" has it's origins in the word "columba," which is Latin for "pigeon" or "dove." Early botanical enthusiasts felt that the nectar spurs resembled the heads of a group of doves.

More and more I am coming on board with the idea that etymology can be quite fun.

Photo Credit: Steve (http://bit.ly/NbGbmz)

Further Reading: [1] [2] [3]

High Elevation Record Breakers Are Evidence of Climate Change

December 13, 2016

A new record has been set for vascular plants. Three mustards, two composits, and a grass have been found growing at an elevation of 20,177 feet (6,150 m) above sea level!

Mountains are a brutal place to live. Freezing temperatures, fierce winds, limited soil, and punishing UV radiation are serious hurdles for any form of life. Whereas algae and mosses can often eke out an existence at such altitudes, more derived forms of life have largely been excluded from such habitats. That is, until now. The area in which these plants were discovered measured about the size of a football field and is situated atop an Indian mountain known as Mount Shukule II.

Although stressed, these plants were nonetheless established among the scree of this menacing peak. Most were quite young, having only been there for a few seasons but growth rings on the roots of at least one plant indicated that it had been growing there for nearly 20 years!

All of them have taken the cushion-like growth habit of most high elevation plant species in order to reduce exposure and conserve water. The leaves of each species also contained high levels of sugary anti-freeze, a must in this bitter cold habitat.

The research team, who could only muster a few hours of work each day, believed that the seeds of these plants were blown up there by wind. Because soils in alpine zones are often non-existent, the team wanted to take a closer look at what kind of microbial community, if any, was associated with their roots.

Whereas no mycorrhizal species were identified, the team did find a complex community of bacteria living among the roots that are characteristic of species living in arid, desert-like regions. It is likely that these bacteria came in with the seeds. Aside from wind, sun, and a lack of soil, one of the other great challenges for these plants is a short growing season. In order to persist at this elevation, the plants require a minimum of 40 days of frost-free soil each year.

Because climate change is happening much faster in mountainous regions, it is likely that such favorable growing conditions are a relatively recent phenomenon. The area in question has only recently become deglaciated. As average yearly temperatures continue to increase, the habitable zone for plants such as these is also moving up the mountain. The question is, what happens when it reaches the top? Once at the peak, plants have nowhere to go. One of the greatest issues alpine plants face is that they will gradually be squeezed off of these habitat islands.

Although expanding habitable zones in these mountains may sound like a good thing, it is likely a short term benefit for most species. Whereas temperature bands in the Tibetan mountains are moving upwards at a rate of 20 feet (6 m) per year, most alpine plants can only track favorable climates at a rate of about 2 inches (0.06 m) per year. In other words, they simply can't keep up. As such, this record breaking discovery is somewhat bitter sweet.

Photo Credit: [1]

Staying Warm: An Alpine Plant Approach to Reproduction

December 5, 2016

Photo by Richard Jones licensed under CC BY-NC-ND 2.0

Things are beginning to cool down throughout the northern hemisphere. As winter approaches, most plant species begin to enter their dormancy period. Very few plants risk wasting their reproductive efforts in the chill of late fall, having gotten most of it out of the way during the warm summer months. This is easy enough for low elevation (and low latitude) plants but what about species living in the high arctic or alpine habitats. Such habitats are faced with cold, harsh conditions year round. How do plants living in these zones deal with reproduction?

These limitations are overcome via physiology. For starters, plants living in such extreme habitats often self pollinate. Insects and other pollinators are too few and far between to rely solely upon them as a means of reproduction. Also, the flowers of most cold weather plants are heliocentric. This means that, as the sun moves across the sky, the flowers track its path so that they are constantly perpendicular to its rays. This maintains maximum exposure to this precious heat source.

Additionally, many arctic and alpine plants have parabolically shaped flowers. This amplifies the incoming radiation being absorbed by the flower. Experiments have shown that flowers that have been shaded from the heat of the sun had a dismal seed set of only 8% whereas plants exposed to the sun had an elevated seed set of 60%.

For plants in these habitats, its all about persistence. Low reproductive rates are often offset by extremes in longevity. This is one of the many reasons why hikers must remember to tread lightly in these habitats. Damages incurred by even a single careless hiker can take decades, if not centuries, to recover.

Photo Credit: [1]

Snowdrops

April 14, 2015

Photo by Gideon Chilton licensed under CC BY-NC 2.0

Few plants in temperate horticulture signal the end of winter better than snowdrops. Come February in the northern hemisphere, these herbaceous bulbs begin popping up, often through a layer of snow. They refuse to be beaten back by freak snow storms and deep frosts.

Snowdrops are native to a wide swath of the European continent. Like many spring ephemerals, they love moist, rich forests and will often escape into the surrounding environment. Taxonomically speaking, there are something like 20 species currently recognized. From what I can tell, this number has and continues to fluctuate each time someone takes a fresh crack at the group. What is certain is that the original distributions of many species have been clouded by a long history of associating with humans. For instance, whereas Galanthus nivalis is frequently thought of as being native to the UK, records show that it was only first introduced in 1770.

Map by Nalagtus licensed under CC BY-SA 4.0

Because we find them so endearing, snowdrops have become commonplace in temperate areas around the world. Reproduction for most of the garden escapees occurs mainly by division of their bulbs. As such, most plants you see in gardens and parks are clones. Pollination in snowdrops is frequently quite poor. This has been attributed to the lack of pollinating insects out and about during the cold months in which snowdrops flower. Bumblebees are some of the few insects up early enough to take advantage of their white blooms and, when seed set does occur, the plants rely on ants as their main seed dispersers.

Contrary to their ubiquitous presence around the globe, the IUCN lists some snowdrop species as near threatened in their home range. The genus Galanthus contains some of the most heavily collected and traded wild bulbs in the world. Pressure from the horticultural trade coupled with habitat destruction and climate change may push some species to the brink of extirpation throughout Europe in the not-so-distance future.

Photo Credit: [1] [2]

Further Reading: [1] [2] [3] [4]

http://www.arkive.org/snowdrop/galanthus-nivalis/

Noble Rhubarb

January 19, 2015

The Himalayas. If there was ever a natural wonder worthy of the title "epic" it would certainly be these towering peaks. Home to some of the tallest points on our planet, these ragged peaks are best known for the near insurmountable challenges faced by adventurers from all around the world. Considering their elevation, it would seem that permanent life simply isn't possible on these mountains. However, this could not be further from the truth. Among sprawling shrubs and diminutive herbs towers one of the most peculiar plants known to the world. To make things more interesting, it is a relative of rhubarb, a denizen of gardens and pies throughout much more hospitable climates.

Meet the noble rhubarb, Rheum nobile. Growing at elevations between 13,000 and 15,000 feet (4000–4800 m), this species is quite deserving of its noble status. Plants growing at such elevations face some serious challenges. Temperatures regularly drop well below freezing and there is no shortage of damaging UV radiation. As with most alpine zones, a majority of plants cope with these conditions by growing prostrate over the ground and taking what little refuge they can find behind rocks. Not Rheum nobile. This member of the buckwheat family can grow to heights of 6 feet, making it easily the tallest plant around for miles.

The most striking feature of this plant is the large spire of translucent bracts. These modified leaves contain no chlorophyll and thus do not serve as centers for photosynthesis. Instead, these structures are there to protect and warm the plant. Tucked behind the bracts are the flowers. If they were to be exposed to the elements, they would either freeze or be fried by UV radiation. Instead, these ghostly bracts contain specialized pigments that filter out damaging UV wavelengths while at the same time creating a favorable microclimate for the flowers and seeds to develop. In essence, the plant grows its own greenhouse.

Photo by Mark Horrell licensed under CC BY-NC-SA 2.0

As a result, temperatures within the plant can be as much as 10 degrees warmer than the ambient temperatures outside. At such elevations, this is a real boost to its reproductive efforts. Even more of a challenge is the fact that at this elevation, pollinators are often in short supply. Plants have to do what they can to get their attention. Not only does Rheum nobile offer a visual cue that is in stark contrast to its bleak surroundings, it also goes about attracting pollinators chemically as well.

Rheum nobile has struck up a mutualistic relationship with fungus gnats living at these altitudes. The plant produces a single chemical compound that attracts the female fungus gnats. The females lay their eggs in the developing seeds of the plant but, in return, pollinate far more flowers than they can parasitize. These organisms have managed to strike a balance in these mountains. In return for pollination, the fungus gnats have a warm place to raise their young that is sheltered from the damaging UV radiation outside.

Photo Credits: [1] [2] [3]

Further Reading: [1] [2] [3] [4] [5]