There's a Pepper Inside My Pepper!

We received an intriguing surprise the other night while prepping dinner. We cut open an unassuming bell pepper (Capsicum annuum) only to find a small, yet perfectly formed pepper inside! It seemed to be attached to the placenta along with the seeds. This was the first time we had ever encountered this, but a quick internet search revealed it isn’t necessarily a rare phenomenon. What was going on with this fruit that caused it to form another fruit within?

The quick answer is parthenocarpy or the formation of fruit without fertilization. Indeed, when we cut into this smaller pepper, there were no seeds inside. Some have taken to calling this phenomenon “internal proliferation,” but the question remained of what caused it to occur in the first place? It can be intentionally induced to produce seedless varieties of various fruits, however, given the “parent” pepper had plenty of seeds, this pepper within a pepper didn’t seem too intentional.

Another internet search revealed that this is an undesirable trait in the pepper trade. Pepper growers will actively select against plants that produce these internal proliferations. However, I have found it difficult to track down any real concrete explanations as to why it happens. Some have suggested that damage to the ovules or other external stressors such as temperature swings can occasionally induce them. Despite the validity of these hypotheses, few have actually bothered to collect and analyze any data.

I did find at least one paper that discussed something called “aberrant ovules” in peppers and their photographs certainly showed internal growths that looked a lot like what we observed in our pepper. These aberrant ovules ranged in appearance from what are essentially mini peppers to mutant blobs of colorful ovary tissue. The only sound conclusions I really took away from their work was that there does seem to be some evidence that genes are involved. They outlined an experiment in which some genetic lineages of peppers were significantly more likely to produce fruits with aberrant ovules than others. That being said, they did not venture much in the way of a trigger for inducing them. That was about as far as I got before I had to attend to other things in life like enjoying the meal we were making.

Regardless of the cause, it was an interesting and unexpected experience to open up this pepper only to find another pepper inside. We ended up eating the little fruit too, and it was just as yummy as the pepper that housed it!

Further Reading: [1] [2]

My Unforgettable Encounter with a Fevertree

When someone asks you if you would like to see a wild fever tree, you have to say yes. As a denizen of cold climates defined by months of freezing temperatures, I will never miss an opportunity to encounter any species in its native habitat that cannot survive frosts. This was the scenario I found myself in last week as friend and habitat restoration specialist for the Atlanta Botanical Garden, Jeff Talbert, was showing us around a wonderful chunk of Florida scrubland he has been managing over the last few years.

He drove our small group over to an area that, up until a year or two ago, was completely choked with swamp titi (Cyrilla racemiflora). Like many habitats throughout southeastern North America, this patch of Florida scrub is dependent on regular fires to maintain ecological function. Without it, aggressive shrubs like titi completely take over, choking out much of the amazing biodiversity that makes this region unique. Jeff and his team have been very busy restoring fire to this ecosystem and the results have been impressive to say the least.

We walked off the two-track, down into a wet depression and were greeted by an impressive population of spoon-leaf sundews (Drosera intermedia), which is a good sign that water quality on the site is improving. After a few minutes of sundew admiration, Jeff motioned for us to look upward towards the surrounding tree line. That’s when we saw it. Growing up out of the small seep that was feeding this wet depression was a spindly tree with bright pink splotches decorating its canopy. This was to be my first encounter with a fevertree (Pinckneya bracteata).

A few of us were willing to get our feet wet and were rewarded with a close look at the growth habit of this incredible tree. Clustered at the end of its spindly branches are dark green, ovate leaves that give the tree a tropical appearance. Erupting from the middle of some of those leafy branches were the inflorescences. These are what produce the pink splotches I could see in the canopy of larger individuals. They remind me a lot of a poinsettia and at first, I thought this tree might be a member of the genus Euphorbia. Indeed, the pink coloration comes from a handful of rather large, leaf-like sepals attached to the base of each inflorescence.

Upon seeing the flowers, I instantly knew this was not a member of Euphorbiaceae. Each flower was long and tubular ending in five reflexed lobes. They are colorful structures in and of themselves, adorned with splashes of pink and yellow. After a bit of scrutiny, our group was finally able to place this within its true taxonomic lineage, the coffee family (Rubiaceae).

Within the coffee family, fevertree is closely related to the genus Cinchona. Like Cinchona, the fevertree produces quinine and other alkaloids that are effective in treating malaria. Fevertree has been used for millennia to do just that, hence the common name. It also seems fitting that fevertrees tend to grow in wetland habitats where mosquitos can be abundant. However, this is by no means an obligate wetland species. Those who have grown fevertree frequently succeed in establishing plants in dry, upland habitats as well. Perhaps highly disturbed wetlands are some of the few places where this spindly tree can avoid intense competition from other forms of vegetation.

Fevertrees do need regular disturbance to persist. They are not a large, robust tree by any means and can easily get outcompeted by more aggressive vegetation. However, this species does have a trick that enables individuals to persist when disturbances don’t come frequent enough. Fevertree is highly clonal. Instead of producing a single trunk, it sends out numerous stems in all directions in search of a gap in the canopy. This clonal habit allows it to eek out an existence in the gaps between its more robust neighbors until disturbances return and clear things out.

This clonal habit is also very important when it comes to reproduction. Fevertree requires a decent amount of sunlight to successfully flower and set seed. By using its clonal stems to find light gaps, it can at least guarantee some level of reproduction until fires, floods, or some other form of canopy clearing disturbance frees up enough space for it to prosper and its seeds to germinate. However, its clonal habit can also hurt its reproductive capacity over the long term if recruitment of new individuals does not occur.

Fevertree is considered self-incompatible. In other words, its flowers cannot be pollinated via pollen from a genetically identical individual. As more and more clonal shoots are produced, the tree effectively increases the chances that its own pollen will end up on its own flowers. This is yet another important reason why regular disturbance favors fevertree reproduction. Fevertree seeds need light and bare ground to germinate, which is usually provided as fires and other disturbances clear the canopy and open up bare ground. Only then can enough unrelated individuals establish to ensure plenty of successful pollination opportunities.

With its long, tubular flowers and bright pink sepals, fevertrees don’t seem to have any trouble attracting pollinators, which mainly consist of ruby-throated hummingbirds and bumblebees. Only these organisms have what it takes to successfully access the pollen and nectar rewards of this plant and travel the distances necessary to ensure pollen ends up on unrelated individuals. The seeds that result from pollination are winged and can travel a decent distance with a decent wind. With any luck, a few seeds will end up in another disturbance-cleared wet area and usher in the next generation of fevertrees.

I am so happy that restoration activities at this site are making more suitable habitat for this unique tree. Looking around, we saw many more small individuals starting to emerge where there was once a dense canopy of titi. Hopefully with ongoing management, this population will continue to grow and spread, securing the a future for this species in a region with an ever-growing human presence. If you ever find the opportunity to see one of these trees in person, do yourself a favor and take it!

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

Roadside Seeding and Bluebonnet Genetics

Photo by Adam Baker licensed under CC BY-NC 2.0

The mass blooming of bluebonnets (Lupinus texensis) is truly one of southern North America’s most stunning natural spectacles. Celebrated across its native range, the bluebonnet has greatly benefited from supplemental planting by humans. Indeed, in states like Texas, hundreds of miles of roadsides are seeded with bluebonnets every year and the end result can be spectacular. The popularity of mass seeding of this wonderful species has led some to ask how the practice may be affecting the genetic diversity of the species throughout its range.

Before we get into population genetics, it is worth getting to know this plant a bit better. Bluebonnets are a type of winter annual lupine endemic to southern Texas and northern Mexico. Their highly camouflaged seeds usually begin to germinate late in the fall after enough weathering has weakened the hard seed coat the protects the embryo. Seedlings remain small throughout fall and winter, rarely growing more than a few tiny, palmate leaves. Once spring arrives, growth accelerates.

Within a few short weeks, most individuals will have already pushed up a spike chock full of their characteristic blue and white flowers. Their main pollinators are bumblebees such as the American bumblebee (Bombus pensylvanicus). Once pollinated, plants don’t waste any time producing seeds. Bluebonnets utilize an explosive seed dispersal mechanism, which can be pretty fun to witness in person. As the pods mature, they gradually dry out, creating a lot of tension. Eventually, the tension within the pod becomes so great that the whole structure gives in and explodes, launching seeds as far as 13 feet (4 m) away from the parent plant where they will wait until fall returns.

Photo by Danny Barron licensed under CC BY-NC-ND 2.0

Although 13 feet may sound like a decent distance for a plant the size of a bluebonnet to launch its seeds, it pales in comparison to many other forms of seed dispersal. As such, one would expect bluebonnets within any given population to be more closely related to one another than they would be to bluebonnets growing in other, more distant populations. It is this assumption that led scientists to ask how intentional seeding of bluebonnets may be affecting the genetics of these plants. Before we jump into their findings, I first want to make one thing very clear.

I am in no way disparaging intentional seeding of native plants, especially not by municipalities! I think the practice of seeding with native plants is vital to any environmental management practice we humans undertake. That being said, it is important that we try to understand how any of our actions may be impacting any aspect of biodiversity. Now, onto the research.

By sampling the DNA of both natural and intentionally planted populations across a wide swath of bluebonnet’s endemic range, scientists revealed an intriguing picture of their genetic structure. Simply put, there is surprisingly little. Where they expected to find genetic differences among populations, they instead found a lot of uniformity. It is almost as if populations were mixing their genetic material across the range of the species.

There are a few possible explanations that could explain this pattern. For one, it is possible that estimates of seed dispersal in this species are vastly underestimated. Perhaps seed dispersal events regularly exceed previous estimates of around 13 feet. Along a similar line of reasoning, it is also possible that bluebonnets don’t rely solely on ballistics to get their seeds out into the environment. If birds or mammals occasionally move seeds long distances, this could eventually lead to genetic mixing among different populations. However, such possibilities are unlikely given the nature of bluebonnet seeds and the fact that animals are far more likely to act as seed predators for bluebonnets than seed dispersers.

Scientists have also put forth the possibility that bluebonnets in both natural and cultivate populations simply haven’t been isolated long enough for genetic differences to emerge among populations. However, this does not explain why there is so few genetic differences among widely separated natural populations.

The most likely reason why bluebonnets are so alike genetically is intentional planting. Though plenty of effort is put into ensuring that bluebonnet plantings are done using seeds sourced within 124 miles (200 km) from the planting site, we simply can’t rule out the idea that genes from individuals sourced from cultivation are not completely swamping the gene pools of wild populations as they are sowed along roadsides and into other planting projects.

To be fair, though these findings are compelling, we can’t necessarily jump to any conclusions as to whether such genetic swamping is a net negative or net positive for bluebonnets across their range. The scientists involved with the study do mention that swamping of fractured wild bluebonnet populations with genes of cultivated individuals could prove beneficial for the species, especially as the impact of human development continues to increase. It is possible that cultivated individuals that are selected because they perform well in human-dominated environments are introducing genes into wild populations that may allow them to cope with the increased human disturbances.

The alternative argument to that point is that we are swamping wild populations with potentially deleterious alleles at a faster rate than natural selection can purge them from the population. If this is the case, we may see a gradual decline in some populations that grow more and more out of sync with their local environment.

Though it is far too early to draw any hard fast conclusions about the impacts of genetic swamping, the genetic patterns that have been uncovered among bluebonnets are important to document. Now that we know that genetic diversity is low across populations, we can begin to dive deeper into both the mechanisms that created said patterns and their impacts on various populations. Once again, this is not an argument against intentional seeding and planting of native plants. Instead, it is a nice reminder that even the best intentions can have vast and unintended consequences that we need to study in more detail.

Further Reading: [1]

The Ceropegias Welcome a New Member

Photos by David Styles

The genus Ceropegia is home to some of my favorite plants. Not only are they distant cousins of the milkweeds (Asclepias spp.), they sport some of the most interesting floral morphologies whose beauty is only exceeded by their fascinating pollination syndromes. Recently, Ceropegia expert and friend of the podcast Dr. Annemarie Heiduk brought to my attention the recent description of a species named in her honor.

Ceropegia heidukiae hails from KwaZulu-Natal, South Africa, and, at current, is believed to be endemic to a habitat type called the Northern Zululand Mistbelt Grassland. Morphologically, it has been described as an erect perennial herb. Unlike many of its cousins, C. heidukiae does not vine. Instead, it grows a slender stem with opposite, ovate leaves that just barely reaches above the surrounding grasses. By far the most striking feature of this plant are its flowers.

Photos by David Styles.

Ceropegia heidukiae produces elaborate trap flowers at the tips of its slender stems during the month of December (summer in the Southern Hemisphere). Each flower is comprised a greenish-gold, striped tube made of fused petals and topped with a purple, star-like structure with fine hairs. These flowers were the key indication that this species was previously unknown to science. Additionally, a sweet, acidic scent was detected during the relatively short blooming period.

Their beauty aside, the anatomy and scent of these flowers hints at what may very well be a complex and specific pollination syndrome. Indeed, scientists like Dr. Heiduk are revealing amazing chemical trickery within the flowers of this incredible genus, including one species that mimics the smell of dying bees. Who knows what kinds of relationships this new species has evolved in its unique habitat. Only plenty of observation and experimentation will tell and I anxiously await future studies.

A view of the Northern Zululand Mistbelt Grassland where Ceropegia heidukiae was found.

Sadly, C. heidukiae lives in one of South Africa’s most threatened habitat types. South Africa’s Biodiversity Act currently classifies the Northern Zululand Mistbelt Grassland as endangered due to factors like timber plantations and unsustainable grazing. Hopefully with the recognition of unique species like C. heidukiae, more attention can be given to sustainable use of the Northern Zululand Mistbelt Grassland such that both the people and the species that rely on it can continue to do so for generations to come.

Photo Credits: David Styles

Further Reading: [1] [2]

Some Magnolia Flowers Have Built-In Heaters

Magnolia denudata. Photo by 阿橋 HQ licensed under CC BY-SA 2.0

There are a lot of reasons to like magnolias and floral thermogenesis is one of them. That’s right, the flowers of a surprising amount of magnolia species produce their own heat! Although much more work is needed to understand the mechanisms involved in heat generation in these trees, research suggests that it all centers on pollination.

Magnolias have a deep evolutionary history, having arose on this planet some 95+ million years ago. Earth was a very different place back then. For one, familiar insect pollinators like bees had not evolved yet. As such, the basic anatomy of magnolia flowers was in place long before bees could work as a selective pressure in pollination. What were abundant back then were beetles and it is thought that throughout their history, beetles have served as the dominant pollinators for most species. Indeed, even today, beetles dominate the magnolia pollination scene.

Magnolia sprengeri. Photo by Aleš Smrdel licensed under CC BY-NC 2.0

Beetles are generally not visiting flowers for nectar. They are instead after the protein-rich pollen within each anther. It seems that when the anthers are mature, beetles are very willing to spend time munching away within each flower, however, keeping their attention during the female phase of the flower is a bit trickier. Because there are no rewards for visiting a magnolia flower during its female phase, evolution has provided some species with an interesting trick. This is where heat comes in.

Though it varies from species to species, thermogenic magnolias produce combinations of scented oils that various beetles species find irresistible. That is, if they can pick up the odor against the backdrop of all the other enticing scents a forest has to offer. By observing floral development in species like Magnolia sprengeri, researchers have found that as the flowers heat up, the scented oils produced by the flower begin to volatilize. In doing so, the scent is dispersed over a much greater area than it would be without heat.

Magnolia tamaulipana. Photo by James Gaither licensed under CC BY-NC-ND 2.0

Unlike some other thermogenic plants, heat production in magnolia flowers doesn’t appear to be constant. Instead, flowers experience periodic bursts of heat that can see them reaching temperatures as high as 5°C warmer than ambient temperatures. These peaks in heat production just to happen to coincide with the receptivity of male and female organs. Also, only half of the process is considered an “honest signal” to beetles. During the male phase, the beetles will find plenty of pollen to eat. However, during the female phase, the scent belies the fact that beetles will find no reward at all. This has led to the conclusion that the non-rewarding female phase of the magnolia flower is essentially mimicking the rewarding male phase in order to ensure some cross pollination without wasting any energy on additional rewards.

The timing of heat production also changes depending on the species of beetle and their feeding habits. For species like the aforementioned M. sprengeri, which is pollinated by beetles that are active during the day, heat and scent production only occur when the sun is up. Alternatively, for species like M. tamaulipana whose beetle pollinators are nocturnal, heat and scent production only occur at night. Researchers also think that seasonal climate plays a role as well, suggesting that heat itself may be its own form of pollinator reward in some species. Many of the thermogenic magnolias bloom in the early spring when temperatures are relatively low. It is likely that, aside from pollen, beetles may also be seeking a warm spot to rest.

Personally, I was surprised to learn just how many different magnolias are capable of producing heat in their flowers. When I first learned of this phenomenon, I thought it was unique to M. sprengeri but I was wrong. We still have a lot to learn about this process but research like this just goes to show you that even familiar genera can hold many surprises for those curious enough to seek them out.

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

Meet the Golden Lotus Banana

Photo by Linda De Volder licensed under CC BY-NC-ND 2.0

While perusing the internet the other day, I scrolled past an image of what looked like the physical manifestation of the sun emoji on my phone. The bright yellow flash was so striking that it caused me to pause and scroll back to the source. I was pleasantly surprised to see that the sun-like object belonged to something botanical. I was even more surprised to find out that it was produced by a unique cousin of the banana called the golden lotus banana (Musella lasiocarpa).

The golden lotus banana is an oddball in many ways. For starters, it has a confusing taxonomic history. For many years, this odd plant has bounced back and forth between what was originally the only two genera in the banana family (Musaceae). Indeed, it has many outward characteristics that could firmly land it in either the genus Musa or the genus Ensete. Still, this plant is strange enough that numerous taxonomists have taken their own stab at narrowing down its correct placement. It wasn’t until DNA analyses revealed it to be so distinct from either of these genera that it warranted its own unique taxonomic placement. Thus, the monotypic genus Musella was born.

Photo by FarOutFlora licensed under CC BY-NC-ND 2.0

The plant itself is well known and widely cultivated throughout its home range in the Yunnan province of China. In fact, the golden lotus banana is so widely cultivated in this region as food for both humans and cattle alike, that experts couldn’t quite figure out if there were any wild populations left. It wasn’t until relatively recently that some wild populations were found. Sadly, these populations are under threat of being completely extirpated as much of the conifer-oak forests it calls home have been highly fragmented and degraded due to human activities. At least its popularity in cultivation means this species is not likely to go completely extinct any time soon.

The golden lotus banana is rather interesting in form. When you look for pictures of this species around the web, you are likely to pull up images of a stubby, nearly leafless stalk tipped with the bright yellow bracts that look like the rays of a cartoonish sun. Apparently, plants can lose many of their leaves in cultivation around the time the inflorescence matures, giving the impression that it never had any to begin with. Of course, the plant does produce typical banana-like leaves for most of the year. As mentioned, the amazing inflorescence is borne at the tip of what looks like a small, woody trunk, but in reality is actually the fused petioles of their leaves. All members of the banana family are, after all, overgrown herbs, not trees.

As is typical with this family, the flowers don’t all ripen at once. Instead, they begin at the base and gradually ripen over time, revealing consecutive whirls of tubular flowers surrounded by bright yellow bracts, though a variant population that produces red bracts was recently described as well. Interestingly, the golden lotus banana differs from its banana cousins in that its flowers are not pollinated by bats or birds. Instead, bees and wasps comprise the bulk of floral visitors, at least among cultivated populations. The first flowers to mature are male flowers that produce a small amount of nectar and copious amounts of pollen. Only the flowers near the base of the inflorescence are female and they produce a lot more nectar than the male flowers.

Photo by Linda De Volder licensed under CC BY-NC-ND 2.0

Research has shown that bees are far more likely to visit female over male flowers and their visits to female flowers last much longer. This is likely due to the differences in nectar production, but the end result is that by encouraging bees to spend less time on male flowers and more time on female flowers, each plant greatly increases the chances that pollen of unrelated individuals will end up on the stigma. After pollination, tiny fruits are formed, however, from what I have read they are largely inedible to humans. Once the fruits ripen and seeds are dispersed, the flowering stalk dies back and is replace by a fresh new growth stalk from the underground rhizome.

The next time you find yourself at a botanical garden with a decent tropical plant collection, keep an eye out for the golden lotus banana. Outside of China, this species has gained some popularity among specialist plant growers and you just might be lucky to stumble across one in the process of blooming.

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

A Closer Look at Hyacinths

Photo by Radu Chibzii licensed under CC BY-SA 2.0

They say that our sense of smell is very closely tied with the formation of memories. It is around this time of year that I am strongly reminded of the power of that link. All I have to do is catch a whiff of a blooming hyacinth and I am immediately transported back to childhood where spring time gatherings with the family were always accompanied by mass quantities of these colorful bulbs. Indeed, the smell of hyacinths in bloom will forever hold a special place in my mind (and heart).

Because it is spring in my neck of the woods and because my partner recently came home with a wonderful potted hyacinth to add some springy joy our apartment, I decided to take a dive into the origins of these plants. Where do they come from and how do they live in the wild? Certainly they didn’t originate in our gardens.

To start with, there are surprisingly few true hyacinths in this world these days. Whereas many more spring flowering bulbs were once considered members, today the genus Hyacinthus is comprised of only three species, H. litwinovii, H. transcaspicus, and the most famous of them all, H. orientalis. All other “hyacinths” are hyacinths in name only. These plants were once considered members of the lily family (Liliaceae) but more recent genetic work places them in the asparagus family (Asparagaceae).

All three species of hyacinth are native to the eastern Mediterranean region, throughout the Middle East, and well into southwestern Asia. As you might imagine, there is a fair amount of geographical variation across populations of these plants. For instance, H. orientalis itself contains many putative subspecies and varieties. However, their long history of human cultivation has seen them introduced and naturalized over a much wider area of the globe. Generally speaking, these plants tend to prefer cool, higher elevation habitats and loose soils.

As many of you already know, hyacinths are bulbous plants. Throughout most of the year, they lie dormant beneath the soil waiting for warming spring weather to signal that it’s growing time. And grow they do! Because their leaves and inflorescence are already developed within the bulb, hyacinths can rapidly emerge, flower, and leaf out once snow thaws and releases water into the soil. And flower they do! Though selective breeding has resulted in myriad floral colors and strong, pleasant odors, the wild species are nonetheless put on quite a display.

The flowers of wild hyacinths are generally fewer in number and can range in color from almost white or light blue to nearly purple. Their wonderful floral scent is not a human-bred characteristic either, though we have certainly capitalized on it in the horticulture trade. In the wild, these scent compounds call in pollinators who are rewarded with tiny amounts of nectar. It is thought that bees are the primary pollinators of hyacinths both in their native and introduced habitats.

Of course, all of their floral beauty comes down to seed production. Upon ripening, each fruit (capsule) opens to reveal numerous seeds, each with a fleshy attachment called an elaiosome. The elaiosome is very attractive to resident ants that quickly go to work collecting seeds and bringing them back to their colony. However, it isn’t the seed itself the ants are interested in, but rather the elaiosome. Once it is removed and consumed, the seed is discarded, usually in a waste chamber within the colony where it is free to germinate far away from potential seed predators.

Once growth and reproduction are over, hyacinths once again retreat back underground into their bulb phase. Amazingly, these plants have a special adaptation to make sure that their bulbs are tucked safely underground, away from freezing winter temperatures. Throughout the growing season, hyacinths produce specialized roots that are able to contract. As they contract, they literally pull the base of the plant deeper into the soil. This is very advantageous for plants that enjoy growing in loose soils that are prone to freezing. Once underground and away from frost and snow, they lie dormant until spring returns.

I don’t know about you but getting to know how common garden plants like hyacinths make a living in the wild only makes me appreciate them more. I hope this brief introduction will have you looking at the hyacinths in your neighborhood in a whole new light.

Further Reading: [1] [2]

My New Book Has Arrived!

The time has finally come! In Defense of Plants: An Exploration into the Wonder of Plants is now in stores. I thank everyone who pre-ordered a copy of the book. They should be on their way! I still can’t believe this is a reality. I always knew I wanted to write a book and I am eternally grateful to Mango Publishing for giving me this opportunity.

In Defense of Plants is a celebration of plants for the sake of plants. There is no denying that plants are extremely useful to humanity in many ways, but that isn’t why this exist. Plants are living, breathing, self-replicating organisms that are fighting for survival just like the rest of life on Earth. And, thanks to their sessile habit, they are doing so in remarkable and sometimes alien ways.

One of the best illustrations of this can be found in Chapter 3 of my new book: “The Wild World of Plant Sex.” Whereas most of us will have a passing familiarity with the concept of pollination, we have only really scratched the surface of the myriad ways plants have figured out how to have sex. Some plants go the familiar rout, offering pollen and nectar to floral visitors in hopes that they will exchange their gametes with another flower of the same species.

Others have evolved trickier means to get the job done. Some fool their pollinators into thinking they are about to get a free meal using parts of their anatomy such as fake anthers or by offering nectar spurs that don’t actually produce nectar. Some plants even pretend to smell like dying bees to lure in scavenging flies. Still others bypass food stimuli altogether and instead smell like receptive female insects in hopes that sex-crazed males won’t know the difference.

Pollination isn’t just for flowering plants either. In In Defense of Plants I also discuss some of the novel ways that mosses have converged on a pollination-like strategy by co-opting tiny invertebrates that thrive in the humid microclimates produced by the dense, leafy stems of moss colonies.

This is just a taste of what is printed on the pages of my new book. I really hope you will consider picking up a copy. To those that already have, I hope you enjoy the read when it arrives! Thank you again for support In Defense of Plants. You are helping keep these operations up and running, allowing me to continue to bring quality, scientifically accurate botanical content to the world. Thank you from the bottom of my heart.

Click here if you would like to order a copy!

You can also purchase a copy directly from the publisher

The Ancient Green Blobs of the Andes

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]

Book Release Updates!

It’s February, which means In Defense of Plants: An Exploration into the Wonder of Plants comes out this month!! I just wanted to give you all an update on when orders will start shipping.

Due to shipping delays, physical book orders will not begin shipping until February 23rd from all retailers. I apologize for the week-long delay, but COVID has done a number on shipping logistics and the publisher is doing all they can. Stay patient and you will get it within that week.

Also, for those in Europe, North and South East Asia, Oceania, and Canada that are interested in purchasing a copy, In Defense of Plants will be available in those markets as well! Please stay tuned for more availability info.

That being said, anyone who pre-ordered the audio book or ebook version will receive their copy as scheduled on February 16th.

Finally, a massive thank you to everyone who has pre-ordered the book thus far. Your interest has skyrocketed In Defense of Plants to the top of multiple new release lists! For those of you interested in getting their hands on a copy, here are some links:

Amazon- https://amzn.to/3mBA1Ov

Bookshop- https://bit.ly/3lxih5B

Barnes and Noble- https://bit.ly/3qpE570

In Defense of Plants Book Coming February 2021!

I am extremely excited to announce that I have written a book! In Defense of Plants: An Exploration Into the Wonder of Plants is slated for release on February 16th, 2021 wherever books are sold.

“In Defense of Plants changes your relationship with the world from the comfort of your windowsill.

The ruthless, horny, and wonderful nature of plants. Understand how plants evolve and live on Earth with a never-before-seen look into their daily drama. Inside, Candeias explores the incredible ways plants live, fight, have sex, and conquer new territory. Whether a blossoming botanist or a professional plant scientist, In Defense of Plants is for anyone who sees plants as more than just static backdrops to more charismatic life forms.

In this easily accessible introduction to the incredible world of plants, you'll find:

• Fantastic botanical histories and plant symbolism

• Passionate stories of flora diversity and scientific names of plant organisms

• Personal tales of discovery through the study of plants

If you enjoyed books like The Botany of Desire, What a Plant Knows, or The Soul of an Octopus, then you'll love In Defense of Plants.”

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Curly Cucurbits

I’ve grown to really appreciate cucurbits (family Cucurbitaceae) in recent years. From their ambling/climbing habit and often delicious fruits to their beautiful flowers and intimate relationships with a few native bees, this family has a lot to offer. Of course, there are few better ways to get to know plants than by growing them in and around your home and, at least at our place, this summer will go down in history as the summer of the gourd. We are currently growing a handful of species and cultivars and I get a great deal of enjoyment out of watching them grow up the trellis we have provided.

As they climb, cucurbits send out long, thin tendrils (which are actually modified stems) that grab on and wind around any surface they touch. This happens surprisingly quick too. Within only a few minutes of touching a surface, individual tendrils will begin to wind themselves around it. This phenomenon has fascinated people for centuries. I don’t doubt it amused the indigenous cultures that first began cultivating them for food and that amusement continues till this day. Do a web search for cucumber tendrils and you will find countless pictures and blogs showcasing this wonderful anatomical habit.

Despite all the attention, the mechanisms behind this behavior have largely remained a mystery until quite recently. We have known that the initial curling of the tendril is induced by touch. As soon as the cells within the tendril sense contact with a surface, the signal is sent to begin curling. But how do they curl so quickly?

The key to this behavior lies in a two-layered band of specialized cells that run the length of the tendril. Once the signal that the tendril has touched an object has been received, these bands swing into action. One layer of cells will immediately begin to expel water, causing them to contract. Meanwhile, the other layer of cells becomes increasingly stiff and lignified. This creates tension along the length of the tendril, causing it to bend. Oddly enough, this doesn’t happen in the same direction. Take a close look at the tendrils on a cucumber or squash vine and you will notice that each tendril curls in two different directions, separated by a kink or “perversion” (as it is known in the literature) in the middle. This is because the layer of cells on the band that shrinks is different whether you are near the tip or near the base of the tendril.

As many of you reading this are already well aware, the tendrils help to secure the plants as they climb. However, the story is much more interesting than simply anchoring the plants in place. The curling of the tendrils is extremely important when it comes to structural support. If the tendrils did not curl, the plant would be anchored in place with very little wiggle room. As big gusts of wind cause the plant to thrash to and fro or a heavy limb comes crashing down from above, a straight tendril would be far more likely to break under the strain. By adding those opposite twists, the tendrils are able to flex a lot, providing enough movement to keep them from breaking under stress.

If you watch how the tendrils develop over time, their amazing structural support gets even cooler. When stretched, a metal spring looses a lot of its springy-ness. This is not the case for cucurbit tendrils. When stretched, they not only return to their original shape, they curl even tighter. This way, the plant is able to secure itself with varying intensities, allowing for fine tuned adjustments to its structural support. The amount of curling also changes with age. Older tendrils tend to curl more tightly than younger tendrils, especially under strain. As the plant grows, older portions of the stem secure themselves much more strongly via their tendrils. Alternatively, the younger growing portions of the stem need to be a bit more flexible as they anchor themselves to whatever they are climbing on.

So there you have it. The aesthetically pleasing, curly tendrils of your cucurbits serve a very important function in the growth of the plant. Without them, these plants would not only have a hard time climbing, they would also be knocked down by every minor disturbance. The key to their success as vines lies in highly modified stems with an intriguing band of specialized cells that provide them with a physically sound anchoring mechanism.

Learn more in this video:

Further Reading: [1] [2]

The Humble Yet Hardy World of Pineappleweed

For me, an obsession with everything botanical came later on in my academic career. I never paid too much attention to plants as a kid. To be brutally honest, I used to find plants boring. I was too busy preoccupying myself with reptiles, amphibians, and fish. However, if there was ever a plant that was an icon of my care-free childhood existence, it would have to be the humble yet hardy pineappleweed, Matricaria discoidea.

Tearing around on playgrounds for most of the summer months, this little member of the aster family was one of the few species that could handle the endless energy of hundreds of rampaging children and thus was one of the only plants I ever paid much attention to. Still, is wasn’t until much later that I took the time to figure out its identity and natural history.

Pineappleweed is native to parts of northeast Asia and northwestern North America. There are some out there who believe this species may have been brought to North America by paleolithic peoples as a food plant. While this remains to be substantiated, there is no doubt that this is one adaptable species. Now nearly global in its distribution, pineappleweed thrives in some of the harshest habitats imaginable for such a small plant. Its tough stem can handle a lot of foot traffic, making it a common sight along roadsides, city walkways, and of course, playgrounds.

Though at first glance it doesn’t look like it, pineappleweed is a member of the daisy family (Asteraceae). It simply lacks the showy ray florets produced by those of its close cousins. Speaking of cousins, pineappleweed is actually a close relative of chamomile (Matricaria chamomilla). What looks like a single yellow flower is actually a disk made up of many individual flowers densely packed into a dome. The blooms are attractive to tiny syphrid flies but it is not quite known if they are effective pollinators or not. Pineappleweed is also an annual and each disk of flowers can produce thousands of sticky little seeds. This is how this species gets around. Its seeds stick to everything from animal fur to shoes and even car tires. Pineappleweed is yet another species that has benefited from the wanton globalization that humans have enacted upon the world. Keep your eye out for it. It isn’t hard to find and it is certainly a plant worthy of closer inspection.

Further Reading: [1] [2]

A Shout Out to Western Skunk Cabbage

Photo by Martin Bravenboer licensed under CC BY-ND 2.0.

We all have our biases and one of my biggest botanical bias is that I often think of plants from eastern North America before my mind heads further west. I can’t really fault myself for it because so many of my early plant experiences occurred east of the Mississippi. I want to remedy this a bit today by drawing your attention to a wonderful aroid who frequently gets overshadowed by its eastern cousin.

I am of course talking about western skunk cabbage (Lysichiton americanus). This incredibly beautiful plant enjoys a distribution that ranges from southern Alaska to central California and west into Wyoming and Montana. Like its eastern cousin, western skunk cabbage was awarded its common name thanks to the pungent odor it produces. Its blooming period ranges from March into May depending on where they are growing and the inflorescence is truly something to write home about.

The spadix of western skunk cabbage complete with a tiny rove beetle pollinator. Photo by Walter Siegmund lincensed under CC BY-SA 3.0

Emerging from the base of the plant is a bright yellow structure called a spathe. The spathe envelopes the actual flowering parts, a phallic-looking structure covered in flowers called a spadix. The spadix emits various volatile compounds that function as pollinator attractants. However, whereas many would suggest flies are the preferred pollinator, research indicates that a tiny species of rove beetle called Pelecomalium testaceum takes up the bulk of pollination duties for western skunk cabbage throughout much of its range.

The volatile compounds aren’t there to trick the beetles into thinking they are getting some sort of reward. The plant does actually reward the rove beetles with pollen to eat and relatively safe place to mate. We call these types of signals “honest signals” as they act as an honest calling card that signifies rewards are to be had.

A closer look at a Pelecomalium rove beetle. Not sure which species. Photo by Judy Gallagher licensed under CC BY 2.0

Unfortunately, the beauty of western skunk cabbage has seen it enter into novelty garden collections in other temperate regions of the world. In northern Europe, western skunk cabbage has escaped the confines of the garden and is now considered an invasive species in wetlands of that region. Take care to choose you garden plants wisely. Always plant native plants when the option presents itself.

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

Further Reading: [1] [2]

Standing up for staghorn sumac

I would like you to truly meet staghorn sumac (Rhus typhina). I say "truly meet" because I know many of you probably have some knowledge of this plant already. If your parents were as misinformed as mine growing up, you were probably raised to believe this plant will cause the same kind of contact dermatitis as poison sumac. Not the case! Though they are related, you probably have not come into contact with poison sumac (Toxicodendron vernix) unless you were hiking around in a bog or other high-quality wetland. Even then, poison sumac is not a common species. The point I am trying to make here is that staghorn sumac is not poisonous!

Staghorn sumac should be celebrated. Few trees can grow in such degraded soil like this tree can. In fact, it is most often encountered in roadside ditches and at the edges of farm fields. In the fall their canopy turns a brilliant shade of red. Seeing a large patch of sumac in full fall color rivals even maples for intensity. Because of this, staghorn sumac can make a beautiful landscape tree. It forms numerous clones from underground roots so that it is rare to see just one tree. Take a step back and look at a staghorn sumac population. They seem to always take on a dome-like shape. Their cloning habit is what gives sumac stand their dome-like appearance. Once a single individual becomes established, it sends out suckers in all directions. The farther out you go from the center of the dome, the younger the clones get.

Since all individuals that sprout from the original tree are clones, entire patches are usually either male or female. Female trees are those that produce the characteristic red, fuzzy seed spikes. The seeds are acrid, oily drupes that are low in fat. Because of this they do not readily spoil and thus stay on the tree in perfect condition all through winter and even into the next season. All of this adds up to sumac seeds being some of the most highly sought after late winter survival foods for birds and mammals. When everything else has been consumed or has spoiled, sumac drupes become very important meals. It is estimated that over 100 bird species will consume sumac fruits. Insects also relish this tree. Countless numbers of them feed on the leaves, flowers, and seeds.

Most importantly in this day and age, the dead stems and branches of this plant make perfect nesting sites for our native solitary bees. They have a soft pith that is easily hollowed out to make egg laying chambers. From carpenter bees to mud wasps, you can find dozens of species nesting in a sumac patch.

Finally, a delicious but tart tea can be made from steeping the seeds in cool water. The longer they steep the stronger the tea. In the heat of summer it is quite refreshing. However, you may want to filter it through a coffee filter before drinking to avoid ingesting the multitudes of larvae that feed in and among them.

Listen to Episode 297 about sumacs and sumac relatives!

Further Reading: [1]

A Closer Look at Poison Sumac

Photo by JH Miller and KV Miller licensed by CC BY-NC-SA 3.0

Poison sumac (Toxicodendron vernix). The very name is enough to send chills down the spine. At least where I live, this small tree is a bit of a unicorn, often heard of but never seen. That is, unless you know where to look.

A denizen of high quality wetlands, this species is not often encountered by your average hiker. It has a rather spotty distribution in eastern North America as well. I have heard it been said that the best way to find a poison sumac tree is to trip and fall in a bog. The first branch you grab onto will be that of a poison sumac.

Photo by Freekee licensed by CC0 1.0

All jokes aside, coming across one in the wild can be fun. They are a beautiful tree. A member of the family Anacardiaceae, it resembles North America's other sumacs (Rhus sp.), which often gives those innocuous trees a bad reputation. Like its other cousin, poison ivy (Toxicodendron radicans), poison sumac does produce urushiol. Interestingly enough, humans are said to be one of only a small handful of mammals that are susceptible to this compound. The reaction we have to it is not an inherent property of urushiol. Its effects on humans are the result of an allergic reaction. It is said that poison sumac can produce a much harsher reaction than poison ivy. I am one of the lucky ones who does not seem to be allergic to it, which is good news for me as my first encounter with this plant involved most of my face.

Poison sumac fruits are an easy way to tell this tree apart from other sumacs because they produce white-ish fruits, rather than red. Photo by Brett Whaley licensed by CC BY-NC 2.0

Also like poison ivy, poison sumac produces nutritious fruits that birds are particularly fond of. Migratory song birds, especially those that live and breed in wetlands, are the main seed dispersal agents for this species. All in all, the ecological value of species like poison sumac far outweigh the anxieties we feel about them. It is important not to live in fear of species like this. With a little attention to detail, contact can be avoided. Moreover, because it lives in high quality wetlands, the odds of the average person coming into contact with this tree are relatively small compared to other plants. I can only speak highly of a species like this. I just wish we had more high quality wetlands around where they could grow.

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

Further Reading: [1]

Buckthorns Gone Wild

Colletia paradoxa photo by James Gaither licensed by CC BY-NC-ND 2.0

When I think of the buckthorn family (Rhamnaceae), my mind conjures up images of battling with Rhamnus invasions around the Great Lakes or the amazing diversity of Ceanothus in western North America. Never have my thoughts drifted to the bizarre and wonderful genus Colletia. Native to temperate regions of South America, this strange group of spiny shrubs is certainly worth a closer look.

Though new to me, the genus Colletia has been known to science and horticulture since at least the late 1700’s. Hailing from temperate climates, at least two of the five known species of Colletia have found there way into temperate gardens elsewhere. Who could blame gardeners for their fascination with these shrubs. Close inspection of Colletia reveals surprisingly complex morphological features.

Colletia paradoxa

For starters, those large, thick, leaf-like thorns are not leaves at all. They are flattened extensions of the stem called cladodes. Instead of relying on leaves for most of their photosynthetic needs, the various Colletia instead produce chlorophyll in their stems. The cladodes function in much the same way as leaves in that their increased surface area maximizes photosynthetic potential. It is likely that cladodes are a means of conserving valuable resources for the plant.

Instead of producing vulnerable leaves that are subject to plenty of damage, these shrubs simply utilize stem tissues. Stems don’t need to be regrown year after year and by adorning the tips of the cladodes with spines, the plant is better able to protect its photosynthetic tissues. That is not to say that Colletia produce no leaves at all. Colletia will produce leaves near the base of each cladode, especially on younger tissues. Leaves, however, are deciduous and don’t stick around long enough to do much photosynthesizing.

Colletia ulicina with its red, tubular flowers. Photo by FarOutFlora licensed by CC BY-NC-ND 2.0

The flowers of Colletia ulicina are pollinated by hummingbirds. photo by James Gaither licensed by CC BY-NC-ND 2.0

Colletia are made all the more noticeable when they come into flower. For most species, clusters of lightly-scented, white flowers are produced at the base of the cladodes. For these species, insects are thought to be the predominant pollinators. Such is not the case for Colletia ulicina. This species produces sprays of bright red, tubular flowers along its stems. In the wild, these are pollinated by the green-backed firecrown hummingbird (Sephanoides sephaniodes).

Another interesting aspect of Colletia ecology is that they are all nitrogen fixers. To be fair, the plants themselves don’t do any of the fixing. Instead, they produce tiny structures on their roots called “nodules,” and those nodules house specialized bacteria collectively referred to as actinomycetes. In exchange for carbohydrates produced via photosynthesis, these bacteria fix nitrogen from the air. This extra boost of nitrogen allows Colletia to survive and excel in the nutrient-poor soils they call home.

Photo Credits: [1] [2] [3] [4]

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

The Sinewy American Hornbeam

Photo by Richard Webb licensed by CC BY-SA 3.0

Winter is when I really start to notice trees. Admittedly, I am pretty poor when it comes to tree ID and taxonomy but there are a few species that really stand out. One of my all time favorite trees is Carpinus caroliniana.

Carpinus caroliniana goes by a handful of common names including ironwood, musclewood, and American hornbeam. All of these names have been applied to other trees so I'll stick with its scientific name. Finding C. caroliniana is rather easy. All you have to do is look for its unmistakable bark.

Photo by Rob Duval licensed by CC BY-SA 3.0

With smooth, sinewy striations and ridges, it is no wonder how this tree got the name "musclewood." The wood is extremely close-grained and is therefore very hard, earning it another nickname of "ironwood."They are generally small trees, rarely exceeding a few meters in height, though records have shown that some individuals can grow to upwards of 20 meters in rare circumstances. I hope that someday I will be able to meet one of these rare giants.

Carpinus caroliniana is also an indicator of fairly rich soils. Due to their high tolerance for shade, they are often a tree of the mixed hardwood understory. Their foliage resembles that of the family in which they belong, the birch family (Betulaceae).

Photo by Katja Schulz licensed by CC BY 2.0

The caterpillar of the io moth (Automeris io)

An adult io moth (Automeris io). Photo by Andy Reago & Chrissy McClarren licensed by CC BY 2.0

A multitude of insect species utilize C. caroliniana as a larval food source including the famed io moth. In the spring, male and female catkins are born on the same tree and, after fertilization, they are replaced by interesting looking nutlets covered by leaf-like involucres. The seeds are an important food source for a variety of birds, mammals, and insects alike.

The male flowers of Carpinus caroliniana. Photo by Philip Bouchard licensed by CC BY-NC-ND 2.0

Carpinus caroliniana is a tree I could never get bored with. Not only does it have immense ecological value, it is aesthetically pleasing too. Its small size and shade tolerance also makes it a great landscape tree in areas too cramped for something larger. Why this species isn't more popular in native landscaping is beyond me.

Photo Credits: [2] [3] [4] [5] [6] [7] [8]

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

Himalayan snowball plants and their fashionably functional coats

Credit to CGTN Nature film crew

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?

Credit to CGTN Nature film crew

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.

Credit to CGTN Nature film crew

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]

Further Reading: [1] [2]

American Bittersweet

Photo by Peter Gorman licensed by CC BY-NC-SA 2.0

As the bright colors of fall start to give way to the dreary grays of winter, people often go looking for ways to bring a little bit of botanical color indoors to enjoy. It is around this time of year that one species in particular starts turning up in flower arrangements, however, it's not the flowers people are interested in but rather the seeds. This species is so popular in arrangements that its numbers in the wild are facing steep declines.

Meet Celastrus scandens, the American bittersweet vine. It hails from the family Celastraceae, which makes it a distant cousins of Euonymus. This lovely climbing vine is native to much to eastern North America and is most at home growing at the edge of woodlots, thickets, and along rocky bluffs and outcroppings. As mentioned, It isn't the flowers of this species that catch the eye but rather the showy seeds. Encased in bright orange capsules, the crimson berry-like fruits are toxic to us mammals but highly sought after by birds. Despite their toxicity, humans nonetheless covet these fruits. Entire vines are cut down and used in arrangements, especially during the months of fall. This has had detrimental effects on wild populations of American bittersweet.

To add insult to injury, its Asian cousin, Celastrus orbiculatus, has been introduced to this continent and is running amuck in the wild. Known commonly as Oriental bittersweet, this invasive is quickly outpacing its native cousin throughout much of North America. It would seem that Oriental bittersweet can adapt to a wider range of habitat types than American bittersweet and, where these species co-occur, hybridization has been reported. The hybrid offspring are not only fertile, they also have shorter seed dormancy and are much more vigorous growers than either of the parents.

Photo by MN Department of Agriculture

Unfortunately it can be hard to tell these species apart. However, with a little patience and a decent field guide, differences become apparent. The best diagnostic feature I have found is that American bittersweet carries its flowers and fruit on the terminal ends of the stems whereas Oriental bittersweet carries them in the axils of the leaves.

All in all, American bittersweet is a lovely native vine. Its beauty in our eyes has, like so many other plant species, created some serious survival issues. Coupled with the the threat of its highly aggressive Asian cousin, the future of this wonderful species remains uncertain. That being said, this doesn’t have to remain a trend. The good news is that it does quite well as a garden species and many nurseries are beginning to carry the native over the invasive. If you live in eastern North America, consider using this plant in your landscape. It would certainly help. And, if flower arrangements are something you enjoy, please give American bittersweet a break.

Photo Credits: [1] [2] [3] [4]

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