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]

Deer Skew Jack-in-the-Pulpit Sex Ratios

Photo by Michael Janke licensed under CC BY-ND 2.0.

Deer populations in North America are higher than they have been at any point in history. Their explosion in numbers not only leads to series health issues like starvation and chronic wasting disease, it has also had serious impacts on regional plant diversity. Wherever hungry herds of deer go, plants disappear from the landscape. However, the impacts of deer on plants aren’t limited to species they can eat. Research on Jack-in-the-Pulpit (Arisaema triphyllum) has shown that deer can have plenty of surprising indirect impacts on plants as well.

Though I wouldn’t put anything past a hungry deer, plants like Jack-in-the-Pulpit aren’t usually on the menu for these ungulates. Their leaves, stems, and flowers are chock full of raphide crystals that will burn the mouths and esophagus of most herbivores. Still, this doesn’t mean deer aren’t impacting these plants in other ways. Because deer are congregating in high abundance in our ever-shrinking natural spaces, they are having serious impacts on local growing conditions. Wherever deer herds are at high numbers, forests are experiencing soil compaction, soil erosion, and a disappearance of soil leaf litter (also due in part to invasive earthworms). Thanks to issues like these, plants like Jack-in-the-Pulpit are undergoing some serious changes.

Like many aroids, sex expression in the genus Arisaema is fluid and relies on energy stores. Smaller plants store less energy and tend to only produce male flowers when they bloom. Pollen, after all, is cheap compared to eggs and fruit. Only when a plant has stored enough energy over the years will it begin to produce female flowers in addition to males and only the largest, most robust plants will switch over entirely to female flowers. As you can imagine, the ability of a plant to acquire and store enough energy is dependent on the quality of the habitat in which it grows. This is where deer enter into the equation.

High densities of deer inevitably cause serious declines in habitat quality of plants like Jack-in-the-Pulpit. As leaf litter disappears and soil compaction grows more severe, individual plants have a much harder time storing enough energy each growing season. In places where deer impacts are heaviest, the sex ratios of Jack-in-the-Pulpit populations begin to skew heavily towards males because individual plants must grow much longer before they can store enough energy to produce female flowers. It doesn’t end there either. Not only does it take longer for a plant to begin producing female flowers, individual plants must also reach a much larger size in order to produce female flowers than in areas with fewer deer.

Photo by Charles de Mille-Isles licensed under CC BY-ND 2.0.

As mentioned, seed production takes a lot of energy and any plant that is able to produce viable fruits will have less energy stores going into the next season. This means that even if a plant is able to produce female flowers and successfully set seed, they will have burned through so much energy that they will likely revert right back to producing only male flowers the following year, further skewing the sex ratios of any given population towards males. Interestingly, this often results in more individuals being produced via clonal offshoots. The more clones there are in a population, the less diverse the gene pool of that population becomes.

Without actually eating the plants, deer are having serious impacts on Jack-in-the-Pulpit population dynamics. I am certain that this species isn’t alone either. At least Jack-in-the-Pulpit is somewhat flexible in its reproductive behaviors. Other plants aren’t so lucky. I realize deer are a hot button issue but there is no getting around the fact that our mismanagement of their natural predators, habitat, and numbers are having serious and detrimental impacts on wild spaces and all the species they support.

Photo Credits: [1] [2]

Further Reading: [1]

North America's Climbing Fern

There are few things on a hike that get me pumped more than hearing someone call out "Hey, I found something weird over here!" It's even more exciting when that person knows what they are talking about. Sometimes that "something" is a familiar species in a strange spot, or growing in a strange way. Sometimes, however, it is something new and exciting that you have been wanting to encounter for years.

This is how I finally met the American climbing fern (Lygodium palmatum). Tangled among the branches of a shrub was indeed a strange site. The tiny, palmate pinnules are not a dead giveaway as to its true identity. Regardless of looks, this is in fact a fern. It is the only member of this genus native to North America. Its cousins, the Japanese climbing fern (Lygodium japonicum) and the Old World climbing fern (Lygodium microphyllum) can also be found on this continent but they have become very invasive in the southeast.

I know what some of you may be thinking, "if this is a fern then where are the fronds?" This was my first thought as well. My first guess was aimed at each palmate leaf. Wrong. The correct answer is the whole vine! Each climbing vine of this fern is a single frond. The palmate leaves are actually the pinnules. The stem, or rachis as it is called in ferns, twines around branches and stems in a vine-like fashion, unfurling pinnules as it goes. What is most impressive is that these fronds can grow as long as 15 feet. Quite impressive by North American fern standards. Fertile pinnules form at the ends of these fronds. Their lacy appearance is quite beautiful juxtaposed with the hand-like, sterile pinnules.

The American climbing fern can be found growing throughout eastern North America. It is a fern of wet places, enjoying acidic soils and bright sunlight. Unfortunately its preference for wetlands has landed it on threatened and endangered lists throughout its range. Our nasty habit of draining, farming, and developing wetlands means that the American climbing fern (as well as many of the other species it shares its habitat with) is losing habitat at an alarming rate.

Further Reading:
http://plants.usda.gov/core/profile?symbol=LYPA3

The Shape-Shifting Star Chickweed

Photo by BlueRidgeKitties licensed under CC BY-ND 2.0.

Star chickweed (Stellaria pubera) has been called North America’s showiest chickweed and I am inclined to agree. Come mid-spring, this lovely woodland plant produces wonderful white flowers that measure about 1/2 inch across and are ringed by five petals so deeply notched that there appear to be ten. Star chickweed’s floral display takes place rather close to the ground on small, fuzzy shoots but as the flowering window for this species begins to close, a change takes place within the plant. By mid-summer, star chickweed will have grown into something completely different.

As mentioned, flowering for star chickweed occurs close to the ground. During this time, its stems don’t elongate more than a few inches and its leaves are broad, blunt, and sessile. Once seed has been set, star chickweed goes through another growth spurt. New stems begin to grow that are much more vigorous in nature than the flowering shoots. They sprout up from the base of the plant and completely over-top spring growth. They can reach heights of nearly 12 inches and produce much thinner leaves. These summer shoots are usually sterile and only in rare instances have flowers been reported.

Star chickweed showing low-growing fertile shoots (front) and taller, sterile shoots (back). [SOURCE]

Star chickweed’s shape-shifting abilities have confused many a botanizer over the last century or so. Because the fertile and sterile shoots look completely different from each other and largely occur at different times of the growing season, some early botanists even went as far as to describe them as different species. Why this plant goes through two distinct growth phases is still something of a mystery but I suspect it has a lot to do with energy reserves.

Perhaps star chickweed has evolved this shape-shifting habit to keep up with changes in surrounding vegetation. Early in the year, the tree canopy above hasn’t completely closed and many of its herbaceous neighbors are still putting on growth of their own. As such, star chickweed probably doesn’t experience as much competition for light early in the season. Of course, conditions on the forest floor change drastically as spring gives way to summer. It could be that the taller, more vigorous sterile shoots are better able to compete for light as the forest fills in around star chickweed.

Another mystery that still has yet to be answered is what triggers the change in growth. A study published back in 1942 concluded changing day length alone could not explain it and suggested it may be in response to rising summer temperatures. However, their experiment was not terribly thorough, leaving such conclusions in the realm of speculation. I kind of like that about nature. There is always a new mystery to uncover, always a deeper understanding to gain.

Photo Credits: [1] [2]

Further Reading: [1] [2]

When is a mushroom not a mushroom? When it is a Maltese mushroom, of course!

Photo by Hans Hillewaert licensed under CC BY-ND 2.0.

Meet Cynomorium coccineum aka the Maltese mushroom. Despite the common name and overall appearance, this is not a fungus. It is indeed a plant. Cynomorium coccineum is a holoparasite. It produces no chlorophyl of its own and relies solely on a host plant for all of its water and nutrient needs. It is said to parasitize the roots of halophytes or salt-loving plants and thus, is most commonly found growing in salt marshes in addition to dry, sandy habitats in coastal areas.

Native to the Mediterranian region and extending into parts of Afghanistan, Saudi Arabia, Iran, and Central Asia, this species is really only ever found during the rainy season. Most of its life is spent underground, emerging only to display its flowers. Only when enough energy has been garnished from the host will this plant throw up these strange flower spikes. As you can tell from the picture, the spikes are jam packed with highly reduced flowers. The flowers give off a scent that has been likened to cabbage. It is thought that flies take up the bulk of the pollination of these blooms.

Photo by Alastair Rae licensed under CC BY-ND 2.0.

Photo by Hans Hillewaert licensed under CC BY-ND 2.0.

As you can probably guess by its strange appearance, the taxonomic affinity of this strange parasite has been the subject of much debate. For a long time, many botanists placed it in the family Balanophoraceae but more recent genetic work suggests it belongs in its own family, Cynomoriaceae. It is the only genus within that family but interestingly enough, Cynomoriaceae is located within the order Saxifragales, somewhere near Crassulaceae, making it a distant relative of stonecrops like sedum. No matter where its located on the tree of life, Cynomorium coccineum is surely one of the strangest plants on Earth.

Photo Credits: [1] [2]

Further Reading: [1] [2]

Alligators Increase Plant Diversity

Photo by mbarisson licensed under CC BY-ND 2.0.

When you think of gardening, alligators don’t readily jump to mind. Hang out long enough in places like the Everglades and that might change. I was only recently introduced to the concept of a “gator hole” and I must say, I was surprised what a quick search of the literature revealed. It turns out that alligators are important ecosystem engineers and do a wonderful job at increasing plant diversity in the wetlands they inhabit.

Throughout southeastern North America, gators change their behaviors with the seasons. During the rainy season, alligators can be found floating in open water or sunning themselves on land. Except when hunting, they don’t seem to do anything with much urgency. Their activity level changes during the dry season when water is in short supply. Gators don’t sit back and let nature take its course. They spring into action and create their own aquatic refuges.

As the surrounding landscape begins to dry, gators will excavate holes or pits in the soggy ground called gator holes. These holes hold onto water when most of the surrounding landscape isn’t. The process of digging a gator hole may seem destructive but it all must be placed in the context of the surrounding environment. Most gator habitat exists in low lying areas. In places like the Everglades, there isn’t much topography to speak of. When a gator excavates a gator hole, it creates variation in both hydrology and soil conditions.

Photo by Anita Gould licensed under CC BY-ND 2.0.

Soils that have built up over time are lifted out of the hole and piled into mounds. Mounded soils are not only rich in nutrients, they also dry at different rates, creating a gradient in water availability. Plants that normally can’t germinate and grow in saturated soils find suitable spots to live up on the soil mounds while emergent aquatic vegetation fills in along the parameter. Plants that normally prefer to grow in deeper water can also establish within the gator hole itself. In the midst of fairly uniform marsh vegetation, a gator hole quickly becomes a hotbed of plant diversity. The differences in vegetation can be so stark compared to the surrounding landscape that some scientists can actually map gator holes using aerial scans simply by measuring the differences in infrared radiation given off by the leaves of all the different plants that establish around them.

Of course, all of that plant diversity has a huge effect on other organisms as well. Gator holes become important areas for various reptiles, amphibians, birds, and so much more. The paths that alligators take to and from their holes even act like fire breaks, changing the way fire moves through the landscape, which only increases the heterogeneity of the immediate area. Fish, though occasionally eaten, greatly benefit from the stability of water levels within a gator hole. All in all, gator holes are extremely important habitats. Not only do they support a high diversity of plants and animals alike, they make places like the Everglades even more dynamic than they already are.

Photo Credits: [1] [2]

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

The Deceptive Ways of the Calypso Orchid

Photo by Murray Foubister licensed under CC BY-ND 2.0.

Behold the Calypso orchid, Calypso bulbosa. This circumboreal orchid exists as a single leaf lying among the litter of dense conifer forests. They go virtually unnoticed for most of the year until it comes time to flower.

In early spring, the extravagant blooms open up and await the arrival of bumblebees. Calypsos go to great lengths to attract bumblebees. The flower is said to have a sweet scent. Also, the lip sports small, yellow, hair-like protrusions that are believed to mimic anthers covered in pollen. Finally, within the pouch formed by the lip are two false nectar spurs. All of these are a ruse. The Calypso offers no actual rewards to visiting bumblebees.

Not just any bumblebee will do. For the ruse to work, it requires freshly emerged workers that are naive to the orchid’s deception. Bumblebees are not mindless animals. They quickly learn which flowers are worth visiting and which are not. Because of this, the Calypso has only short window of time in which bumblebees in the vicinity are likely to fall for its tricks. As a result, pollination rates are often very low for this orchid.

The most interesting aspect of all of this is that the so-called "male function" of the flower - pollinia removal - is more likely to occur than the "female function" - pollen deposition. The reason for this makes a lot of sense in context; male function requires a bumblebee to be fooled only once whereas female function requires a bumblebee to be fooled at least twice.

The caveat to all of this deception is that a single Calypso, like all other orchids, can produce tens of thousands of seeds. Each orchid therefore has tens of thousands of potential propagules to replace itself in the next generation. Despite that fact, the Calypso orchid is on the decline. Habitat destruction, poaching, deer, and invasive species are taking their toll. If you care about orchids like the Calypso, please consider supporting organizations like the North American Orchid Conservation Center.

Photo by Murray Foubister licensed under CC BY-ND 2.0.

Photo Credit: [1] [2]

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

Pretty Pantaloons From a Member of the Poppy Family

With delicately dissected foliage and flowers that look like pantaloons, it is hard to believe that Dutchman's breeches (Dicentra cucullaria) are related to the common garden poppy. No matter how incredulous it may seem, they are in fact peculiar members of Papaveraceae. I can't get enough of these lovely spring ephemerals and their beauty is equally matched by their intriguing ecology. This species really is the full package.

At home in mesic deciduous forests, Dutchman's breeches are true spring ephemerals. They are primarily denizens of eastern North America, however, disjunct populations can be found in the Pacific Northwest. These are likely relics of a once wider distribution that was split in two by advancing glaciers during the Pleistocene. Dutchman’s breeches live out their entire lives before the tree canopy closes with a fresh batch of leaves. By mid summer they are little more than dormant bulblets resting below the leaf litter. Like the multitude of spring ephemerals they share the forest with, Dutchman's breeches are vying for pollinators capable of tolerating wide swings in temperature. This is where their peculiar little flowers come in.

Packed away in each spur is a sweet nectary treat. The only insects capable of reaching it are bumblebees (Bombus spp.). With their long tongues, these bees flock to the bright white and yellow flowers with vigor. Aside from the occasional thief who chews a hole at the end of the spur, robust bumblebees have this meal all to themselves. In fact, this relationship is so in sync that nothing else is capable of effectively pollinating the plant.

After a brief flowering period, the plant will set seed. Like many other spring ephemerals, they attach a fleshy structure to their seeds called an elaiosome. This attracts foraging ants in the genus Aphaenogaster, who collect the seeds and take them back to their nests. Once there, the elaiosome is sometimes eaten but mostly the seeds are disposed of in trash middens. In this way, the seeds find a nutrient-rich microclimate safe from seed predators in which to germinate. It is a safe bet that most of the patches you find owe their existence to these industrious little insects.

Further Reading: [1] [2]

Record Breaking Palms

Photo by Vinayaraj licensed under CC BY-ND 2.0.

I like record breaking species. It is always exciting to find out which species produces the largest or smallest of something. Lately (and rightfully so), the titan arum (Amorphophallus titanum) has been getting a lot of attention for its incredible inflorescence. Many have bloomed in botanical gardens over the last few years and each one draws a massive crowd. People flock from far and wide to see that largest unbranched inflorescence in the world. You always see it referred to that way; the largest unbranched inflorescence. That got me to thinking, who produces the largest branched inflorescence in the world?

The answer to this is the talipot palm (Corypha umbraculifera). Native to southern India and Sri Lanka, the talipot palm blows all other branched inflorescences out of the water. Heck, branched or not, looking over its dimensions makes me feel like it puts most floral structures to shame. The branched designation comes from the fact that its flowers aren’t borne on a single stalk but many branching stalks. The proportions of this structure are truly staggering.

A talipot palm topped with a massive white inflorescence. Photo by Cumulus Clouds licensed under CC BY-ND 2.0.

The talipot palm inflorescence can measure upwards of 26 feet (8 m) in length and bear as many as 23.9 million flowers at a time. It has been estimated that if you were to lay out all of the branches and flower stalks end to end, you would have nearly 26,000 feet (8,221 m) of plant material. This is truly epic as far as flowering plants are concerned. Even more amazing is the fact that this epic inflorescence is often produced 65 feet (20 m) up in the air!

As you can imagine, producing such a structure and all of the fruits that result takes an absurd amount of energy. Talipot palms grow for anywhere between 30 and 80 years before blooming. Following pollination, the fruits take another year to mature. Once this job is done, the palm dies. It throws all of its energy into one, truly massive reproductive event. Pretty incredible if you ask me.

During my search, I also came across another interesting record breaking palm, Raphia regalis. This species is native to parts of western Africa where it can be found growing in moist, lowland forests. Raphia regalis has the distinct honor of producing the largest self-supporting leaf in the world. Given what I have read, I would imagine that in a dense forest, it would be extremely difficult to take in the full grandeur of its leaves. They are huge. The current record for a single R. regalis leaf is 82 feet (25.1 m) long. It isn’t a solid leaf but rather a compound leaf made up of much tinnier leaflets. To see one in all of its glory would be a truly special event.

Photos 1911 (above) and 2015 (below) showing the incredible leaf length of Raphia regalis. Photo posted by Dr. Thomas Couvreur and lifted from the book: "from the Congo to the Niger" Vol 2 by A. Schultze

So there you have it. Two incredible plant records held by two incredible palms. Not bad for a quick internet search.

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

Further Reading: [1]

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]

Good News For Mangrove Restoration

Mangrove forests are among the most productive ecosystems on Earth. Bridging the gap between land and sea, these forests function as important habitats for organisms of all shapes, sizes, and ecologies. From a purely structural standpoint, mangrove forests are vital for stabilizing coastlines, reducing erosion, and minimizing damage from storm surges. They are also extremely important habitats for carbon sequestration.

The key component of the carbon storing abilities of mangrove forests involves the formation of peat. Whereas we tend to think of bogs when we think about peat, mangroves form it as well. Peat is the result of the accumulation of partially decomposed vegetation and other organic matter. It’s the partially decomposed part of peat that makes it a major carbon store. Because it doesn’t decompose, all of the carbon locked up in the organic matter stays there instead of entering back into the atmosphere.

As they grow, the roots of mangrove forests accumulate debris and sediments, which builds and builds over time. As the organic layer grows, mangroves grow upward on their propped roots. Over decades and centuries, massive quantities of peat can develop under mangrove forests. This is also one of the ways by which coastal land develops. Needless to say, mangrove forests are extremely important ecosystems.

Photo by Phils 1stPix Licensed under CC BY-NC-SA 2.0

Sadly, because they occur along the coast, mangrove forests the world over have been degraded and destroyed at unsustainable rates. As these forests are razed, the land supporting them erodes, removing all of the accumulated sediments and peat. Not only does this destroy all of the ecological and economic benefits of mangrove forests, it also releases huge quantities of carbon.

In recent years, humans have finally begun to realize the environmental and economic costs of mangrove destruction and many regions are starting to implement mangrove restoration efforts. However, the success of any restoration can sometimes take years or even decades to fully assess. This is where chronosequences come in. By studying mangrove restoration projects at different stages of development, scientists can better understand mangrove restoration efforts over relatively short time periods instead of having to wait for individual projects to age to collect all of their data.

Recently, researchers in Florida decided to look at peat accumulation in various mangrove restoration projects. They looked at mangrove restorations of various ages, spanning 25 years of effort. They found that soil and peat accumulation in these forests is surprisingly rapid. In terms of soil accumulation, restored mangrove forests kept pace with and even outpaced natural mangrove forests within the first 5 years of restoration. Even more exciting, peat accumulation in these restored mangrove forests was very rapid, occurring within only a decade of the completion of a mangrove restoration attempt. When you consider the fact that each of the restoration projects they studied started in nothing but pure sand, these results are extremely encouraging.

The scientists point to mangrove roots as the main driver of soil and peat accumulation in these restored forests. As mangroves grow, their roots expand into the surrounding sand. As roots grow and die, they leave all of that organic matter in the soil. Also, the more roots there are, the more debris like wood, leaves, and sediments get trapped in and around the mangroves. This is why peat accumulation occurs so rapidly. What’s more, as sediment and peat builds up below the mangroves, their height increases. At current, the increase in height of these restored mangrove forests is outpacing the rate of sea level rise in coastal Florida. These are encouraging results when one considers just how fast these coastal habitats are changing as our climate continues to change.

The authors of this research are quick to point out that the fast rates of peat accumulation and mangrove growth are likely to slow as these ecosystems mature. Eventually, many of these processes are likely to balance out. They estimate that it would take at least 55 years for mangrove restoration projects in Florida to match their natural counterparts in terms of ecosystem services. Nonetheless, many components of healthy mangrove ecologies, like herbaceous and juvenile vegetation layers, are already established in restorations long before that 55 year mark.

These results are very exciting. Though there is no substitute for protecting natural mangrove forests (or any wild space for that matter), we need to start putting the pieces of our planet back together. If these data are representative of mangrove restoration efforts across the world, there is hope yet that we can replace at least some of what has been lost. Still, until more of the human race starts to value protecting wild spaces and the species they support, we stand to loose so much more. Support your local land conservancy today!!

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

Further Reading: [1]

Opossum Pollination of a Peculiar Parasite

Floral traits can provide us with insights into the types of pollinators most suited for the job. For many flowering plants, the relationship is relatively easy to understand, but check out the flowers of Scybalium fungiforme. You would be completely excused for not even realizing that these bizarre structures belonged to a plant. The anatomy of those flowers would leave most of asking “what on Earth do they attract?” The answer to this are opossums!

Scybalium fungiforme hails from a peculiar family of parasitic plants called Balanophoraceae and is native to the Atlantic forests of Brazil. Members of this family can be found in tropical regions around the globe and all of them are obligate root holoparasites. Essentially this means that all one ever sees of these plants are their strange flowers. The rest of the plant lives within the vascular system of a host plant’s roots.

The adorable big-eared opossums (Didelphis aurita).

Scybalium fungiforme is particularly strange in that its flowers are covered in scale-like bracts. As such, accessing the flowers would be difficult for most animals. Because its strange blooms superficially resemble some marsupial and rodent pollinated Proteaceae in Australian and South Africa, predictions of a non-flying mammal pollination syndrome were about the only explanations that made sense. Now, with the help of night vision cameras, this prediction has been vindicated.

They key to this unique pollination syndrome lies in those bracts and an interesting aspect of opossum anatomy. Until the scale-like bracts are removed, not much is able to access the floral parts inside. Luckily big-eared opossums (Didelphis aurita) come equipped with opposable toes on their back feet. Upon locating the flowers of S. fungiforme, the opossum uses its back feet to remove the bracts. This unveils a bounty of nectar within. As the opossum feeds, its furry little snout gets covered in pollen. When the opossum visits subsequent flowers throughout the night, pollination is achieved.

Floral visitors of Scybalium fungiforme. b) The big-eared opossum, Didelphis aurita drinking nectar on a plant with five inflorescences (one male and four females). c) The montane grass mouse, Akodon montensis, visiting a plant with about 10 inflorescences and drinking nectar on a female one. d) The Violet-capped Woodnymph hummingbird, Thalurania glaucopis visiting a male and e) a female inflorescence. f) detail of an A. angulata wasp manipulating a male flower to eat pollen. g) Agelaia angulate visiting a female inflorescence with the head inserted among flowers to reach the nectar secreted in the inflorescence receptaculum.

Interestingly, activity doesn’t end when the opossums are done. Enough nectar often remains by the next day that a suite of other animals come to pay a visit to these strange blooms. Day time visitation of S. fungiforme consisted largely of wasps, bees, and even a mouse or two. Researchers were also lucky enough to witness Violet-capped Woodnymph hummingbirds (Thalurania glaucopis) repeatedly visit the flowers for a sip of nectar. It would appear that although the main pollinators of this strange parasite are opossums, the removal of the bracts opens up the flowers for plenty of secondary pollinators as well.

Though this is by no means the only plant to be pollinated by non-flying mammals, this pollination syndrome certainly broadens our understanding of the evolution of pollination syndromes.

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

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]

Should We Be Calling Aquatic Bladderworts Omnivores Instead of Carnivores?

Photo by Leonhard Lenz licensed under CC BY-NC 2.0

As is so often the case in nature, the closer we start to look at things, the more interesting they become. Take, for instance, the diet of some carnivorous bladderworts (Utricularia spp.). These wonderful organisms cover their photosynthetic tissues in tiny bladder traps that rapidly spring open whenever a hapless invertebrate makes the mistake of coming too close to a trigger hair. The unlucky prey is quickly sucked into the trap and subsequently digested.

This is how most bladderworts supplement their growth. As cool as this mechanism truly is, our obsession with the idea that these plants are strict carnivores has historically biased the kinds of investigations scientists attempt with these plants. Over the last decade or so, closer inspection of the contents of aquatic bladderwort traps has revealed that a surprising amount of plant material gets trapped as well. Most of this material consists of single celled algae. Is it possible that at least some aquatic bladderworts also gain nutrients from all of that “vegetable” matter?

The answer to this question is a bit more nuanced than expected. Yes, it does appear that non-animal material frequently ends up in bladderwort traps. Much of this comes in the form of a wide variety of algae species. What’s more, it does appear that algae are broken down within the traps themselves, suggesting that the bladderworts are actively digesting this material. The main question that needs to be answered here is whether or not the bladderworts actually benefit from the breakdown of algae.

Evidence of a nutritive benefit from algae digestion is mixed. Some studies have found that the bladderworts don’t appear to benefit at all from the breakdown of algae within their traps. Alternatively, others have found that bladderworts may benefit from digesting at least some types of algae. These authors noted that there doesn’t seem to be any benefit in terms of additional nitrogen for the bladderwort but instead suggest that other trace nutrients might be obtained in this way.

One of the biggest hurdles in this line of research arises from the fact that we still don’t fully understand the digestive mechanisms of bladderworts. It is possible that some of the algal degradation within bladderwort traps has nothing to do with digestion at all. Instead, it could simply be that algae stuck in the traps eventually dies and rots away. Another major question raised by these observations is how tiny organisms like single celled algae even make it into the traps in the first place. What we can say for sure is most algae are far too small to actually trigger the bladder traps. As such, algae is either getting into the traps passively via some form of diffusion or they are sucked in when other, larger prey is captured.

Some research has even suggested that the benefit of trapping algae may depend on the habitats in which bladderworts are growing. Bladderworts living in more acidic water have shown to capture far more algae than bladderworts in more neutral or alkaline water. This has to do with acidity. Numerically speaking, there is far less zooplankton living in acidic water than algae, which means algae is more likely to end up in the bladders. It could be that the benefits of algae are thus greater for plants living in places where little zooplankton is available. Certainly more work will be needed before we can call bladderworts omnivores but the idea itself is exciting.

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

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

How a cactus from the Andes may be using hairs to attract its bat pollinators

Source: Merlin Tuttle’s Bat Conservation

Plants go to great lengths to attract pollinators. From brightly colored flowers to alluring scents and even some sexual deception, there seems to be no end to what plants will do for sex. Recently, research on the pollination of a species of cactus endemic to the Ecuadorian Andes suggests that even plant hairs can be co-opted for pollinator attraction.

Espostoa frutescens is a wonderful columnar cactus that grows from 1,600 ft (487 m) to 6,600 ft (2011 m) in the Ecuadorean Andes. Like many other high elevation cacti, this species is covered in a dense layer of hairy trichomes. These hairs serve an important function in these mountains by protecting the body of the plant from excessive heat, cold, wind, and UV radiation. Espostoa frutescens takes this a step further when it comes time to flower. It is one of those species that produces a dense layer of hairs around its floral buds called a cephalium. Cacti cephalia are thought to have evolved as a means of protecting developing flowers and fruits from the outside elements. What scientists have now discovered is that, at least for some cacti, the cephalium may also serve an important role in attracting bats.

Bats are famous for their use of echolocation. Because they mainly fly at night, bats rely on sound and scent, rather than sight to find food. More and more we are realizing that a lot of plants have taken advantage of this by producing structures that reflect bat sonar in such a way that makes them more appealing to bats. Some plants, like Mucuna holtonii and Marcgravia evenia, do this for pollination. Others, like Nepenthes hemsleyana, do this to obtain a nitrogen-rich meal.

Espostoa frutescens apparently differs from these examples in that its not about reflecting bat sonar, but rather absorbing it at specific frequencies. Close examination of the hairs that comprise the E. frutescens cephalium revealed that they were extremely well adapted for absorbing ultrasonic frequencies in the 90 kHz range. This may seem arbitrary until you look at who exactly pollinates this cactus.

The main pollinator for E. frutescens is a species of bat known as Geoffroy’s tailless bat (Anoura geoffroyi). It turns out that Geoffroy’s tailless bat happens to echolocate at a frequencies right around that 90 kHz range. Whereas the rest of the body of the cactus reflects plenty of sound, bat calls reaching the cephalium of E. frutescens bounced back an average of 14 decibels quieter.

Essentially, the area of floral reward on this species of cactus presents a much quieter surface than the rest of the plant itself. It is very possible that this functions as a sort of calling card for Geoffroy’s tailless bats looking for their next meal. This makes sense from a communication standpoint in that it not only saves the bats valuable foraging time, it also increases the chances of cross pollination for the cactus. To obtain enough energy from flowers, bats must travel great distances. Anything that helps them locate a meal faster will increase visitation to that flower. By changing the way in which the flowers “appear” to echolocating bats, the cacti thus increase the amount of visitation from bats, which brings pollen in from cacti located over the bats feeding range.

It is important to note that, at this point in time, research has only been able to demonstrate that the hairs surrounding E. frutescens flowers are more absorbent to the ultrasonic frequencies used by Geoffroy’s tailless bat. We still have no idea whether bats are more likely to visit flowers borne from cephalia or not. Still, this research paves the way for even more experiments on how plants like E. frutescens may be “communicating” with pollinators like bats.

Photo by Merlin Tuttle’s Bat Conservation. Please Consider supporting this incredible conservation group!

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]

Salty Succulents

Photo by Leoboudv licensed by CC BY 2.5

Succulent plants come in a variety of shapes, sizes, and colors. They also hail from a variety of plant families. If there is one thing that unites these plants (other than their succulent habit) its that the vast majority of them around found growing in dry places. Whether its the heart of a desert or up in the canopy of a tree, succulence has evolved as a means of storing water. However, those of you living near salt marshes may recognize that a handful of salt marsh plants are succulent as well. How is it that plants so frequently found growing in standing water have evolved a succulent habit? The answer lies in salt.

Salt water is pretty bad for most plants. Just like we get dehydrated from drinking or eating high amount of salt, so too do plants. In general, salt both dehydrates plants and causes issues with nutrient uptake. Such is not the case for genera like Salicornia. Commonly referred to as glassworts, pickleweeds, or picklegrass, the various Salicornia are true salt-lovers.

Photo by OliBac licensed by CC BY 2.0

Taxonomically speaking, the genus Salicornia has been called a “taxonomic nightmare.” Thanks to their highly reduced morphology and extreme phenotypic plasticity, delineating species among the genus is something best left to Salicornia experts. What we do know is that they all belong in the amaranth family, Amaranthaceae. All of this confusion should not take away from your enjoyment of Salicornia. Indeed, there is a lot worth appreciating in this family, including their ability to grow in conditions that would kill most other plants.

Salicornia are not simply salt tolerators that can hang on under saline conditions. They are true salt lovers or ‘halophytes.’ In fact, experiments have shown that various Salicornia grow much better when salt levels are high. This all has to do with the way in which these plants deal with their salty environment. Like all succulents, Salicornia have enlarged vacuoles that store water. However, these large vacuoles store more than good ol H2O. They also store salts and lots of them.

Photo by S.Ahmadihayeri licensed by CC BY-SA 3.0

The secret to Salicornia’s salty success has to do with osmosis. As you may remember from science class, substances in our universe like to move from areas of high concentration to areas of low concentration. In the case of water within the tissues of an organism, this often occurs between biological membranes. As you add salt to water, it actually displaces water molecules such that the more salt you add, the less concentrated the water becomes. That is why salt water dehydrates us. When you surround a cell with salt, water will diffuse out of the cell to balance out the concentrations on both sides of the cell membrane. Salicornia use this to their advantage.

These plants actively take up salt from their environment and dump it into their vacuoles. This means that the concentration of water within the vacuole is less than the concentration of water outside of the cell. Osmosis then takes over and water rushes into the plant’s cells. By concentrating salt in their vacuoles, Salicornia are always ensuring that they are on the receiving end of the water gradient. Water is always moving into these salty plants and not the other way around. By co-opting morphological adaptation to drought, Salicornia are able to conquer a niche that is largely unavailable to most other plant species. It also means that, despite all of the water in their environment, these plants maintain a pleasingly succulent habit.

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

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

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]

What an orchid that smells like rotting meat can tell us about carrion flies

Satyrium pumilum Photo by Bernd Haynold licensed by CC BY-SA 3.0

Orchids are really good at tricking pollinators. Take, for instance, this strange looking orchid from South Africa. Satyrium pumilum is probably obscure to most of us but it is doing fascinating things to ensure its own reproductive success. This orchid both smells and kind of looks like rotting meat, which is how it attracts its pollinators.

It is a bit strange to think of orchids living in arid climates like those found in South Africa but this family is defined by exceptions. That is not to say that Satyrium pumilum is a desert plant. To find this orchid, you must look in special microclimates where water sticks around long enough to support its growth. Populations of S. pumilum are most often found clustered near small streams or hidden under bushes throughout the western half of the greater Cape Floristic Region.

Satyrium pumilum blooms from the beginning of September until late October. As is typical in the orchid family, S. pumilum produces rather intricate flowers. Whereas the sepals are decked out in various shades of green, the interior of the flower is blood red in color. Also, unlike many of its cousins, S. pumilum doesn’t throw its flowers up on a tall stalk for all the world to see. Instead, its flowers open up at ground level and give off an unpleasant smell of rotting meat.

This is where pollinators enter into the picture. It has been found that carrion flies are the preferred pollinator for S. pumilum. By producing flowers at ground level that both look and smell like rotting meat, the plants are primed to attract these flies. The plants are tapping into the flies’ reproductive habits, a biological imperative so strong that they simply do not evolve a means of discriminating a rotting corpse from a flower that smells like one. This is the trick. Flies land on the flower thinking they have found a meal and a place to lay their eggs. They go through the motions as expected and pick up or deposit pollen in the process. Unfortunately for the flies, their offspring are doomed. There is not food to be found in these flowers.

What is most remarkable about the reproductive ecology of S. pumilum is that not just any type of fly will do. It appears that only a specific subset of flies actually visit the flowers and act as effective pollinators. Amazingly, this provides insights into some long-running hypotheses regarding carrion fly ecology.

(A) The habitat of S. pumilum (B) Satyrium pumilum in situ (scale bar = 1 cm). (C–E) Pollination sequence of a S. pumilum flower by a sarcophagid fly in an arena (scale bar for all three photos = 0·5 cm); (C) the fly carrying five pollinaria from other S. pumilum flowers enters an unpollinated flower (D) as the fly moves deeper into the flower towards the right-hand spur, it presses an attached pollinium against the stigma, and its thorax against the right-hand viscidium; (E) as it leaves the flower, the fly has deposited two massulae on the stigma (1), and removed a pollinarium (2) – it now carries six pollinaria. [SOURCE]

Apparently there has been a lot of debate in the fly community over why we see so many different species of carrion flies. Rotting meat is rotting meat, right? Probably not, actually. Fly ecologists have comes up with a few hypotheses involving niche segregation among carrion flies to explain their diversity on the landscape. Some believe that flies separate themselves out in time, with different species hatching out and breeding at different times of the year. Others have suggested that carrion flies separate themselves by specializing on carrion at different stages of decay. Still others have suggested that some flies specialize on large pieces of carrion whereas others prefer smaller pieces.

By studying the types of flies visiting the flowers of S. pumilum researchers did find evidence of niche segregation based on carrion size. It turns out that S. pumilum is exclusively pollinated by a group of flies known as sarcophagid carrion flies. These flies were regularly observed with orchid pollen sacs stuck to their backs and plants seemed to only set seed after they had been visited by members of this group. So, what is it about these flowers that makes them so specific to this group of flies?

The answer lies both in their size as well as the amount of scent they produce. It is likely that the quantity of scent compounds produced by S. pumilum most closely mimics that of smaller rotting corpses. The types of flies that visited these blooms were mostly females of species that lay relatively few eggs compared to other carrion flies. It could very well be that the smaller brood size of these flies allows them to effectively utilize smaller bits of carrion than other, more fecund species of fly. To date, this is some of the best evidence in support of the idea that flies avoid competition among different species by segregating out their feeding and reproductive niches.

Rotting meat smells are not uncommon in the plant world. Even within the home range of S. pumilum, there are other plants produce flowers that smell like carrion as well. It would be extremely interesting to look at what kinds of flies visit other carrion flowers and in what numbers. Like I mentioned earlier, reproductive is such a major part of any organisms life that it may simply be too costly for carrion flies to evolve a means of discriminating real and fake breeding sites. It is amazing to think of what we gain from trying to understand the reproductive biology of a small, obscure orchid growing tucked away in arid regions of South Africa.

Photo Credits: [1] [2]

Further Reading: [1]

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]