In the Wake of Volcanoes

Photo by Geir K. Edland licensed under CC BY-NC-ND 2.0

Recruitment windows are any period of time in which seeds germinate and grow into young plants successfully. Needless to say, they are a crucial component of of any plants' life cycle. For some species, these windows are huge, allowing them ample opportunity for successful reproduction. For others, however, these windows are small and specific. Take for instance the saguaro cactus (Carnegiea gigantea) of the American southwest. These arborescent cacti are famous the world over for their impressive stature. They are true survivors, magnificently adapted to their harsh, dry environment. This does not mean life is a cakewalk though. Survival, especially for seedlings, is measured by the slimmest of margins, with most saguaro dying in their first year. 

Hot, dry days and freezing cold nights are not particularly favorable conditions for young cacti. As such, any favorable change in weather can lead to much higher rates of successful recruitment for a given year. Because of this, saguaro often grow up as cohorts that all took advantage of the same favorable conditions that tipped the odds in their favor. This creates an age pattern that researchers can then use to better understand the population dynamics of these cacti. 

Recently, a researcher from York University noticed a particular pattern in the cacti she was studying. A large amount of the older cacti all dated back to the year 1884. What was so special about 1884, you ask? Certainly the climate must have been favorable. However, the real interesting part of this story is what happen the year before. 1883 saw the eruption of Krakatoa, a volcanic island located between Java and Sumatra. The eruption was massive, spewing tons of volcanic ash into the air. Effectively destroying the island, the eruption was so large that it was heard 1,930 miles away in western Australia. 

The effects of the Krakatoa eruption were felt worldwide. Ash and other gases spewed into the atmosphere caused a chilling of the northern hemisphere. Records of that time show an overall cooling effect of more than 2 degrees Fahrenheit. In the American Southwest, this led to record rainfall from July 1883 to June 1884. The combination of higher than average rainfall and lower than average temperatures made for a banner year for saguaro cacti. Seedlings were able to get past that first year bottleneck. After that first year, saguaro are much more likely to survive the hardships of their habitat. 

The Krakatoa eruption wasn't the only one with its own saguaro cohort. Further investigations have revealed similar patterns following the eruptions of Soufriere, Mt. Pelée, and Santa Maria in 1902, Ksudach in 1907, and Katmai in 1912. What this means is that conservation of species like the saguaro must take into account factors far beyond their immediate environment. Such patterns are likely not unique to saguaro either. The Earth functions as a biosphere and the lines we use to define the world around us can become quite blurry. If anything, this research underlines the importance of a system-based view. Nothing operates in a vacuum. 

Photo Credit: Geir K. Edland

Further Reading: [1] [2]

The Mountain Sweet Pepperbush

This first thing I noticed about the mountain sweet pepperbush (Clethra acuminata) was its bark. There before me was a lanky looking tree with beautiful cinnamon-colored bark that peeled back in thin sheets. The effect was a mottle appearance that didn't seem right for where I was hiking. A closer inspection revealed spikes of flower buds that were weeks away from blooming. This was a species I was going to have to keep my eyes on. 

The mountain sweet pepperbush (sometimes called cinnamonbark) is native to a small chunk of eastern North America from Pennsylvania down into Georgia and Alabama. It enjoys acidic, rocky soils and is perfectly at home in the Appalachian Mountains. It isn't a large tree, topping out around 20 feet or so but what it lacks in stature it makes up for in beauty. 

Come mid summer the long spikes put forth a spray of beautiful white flowers. The trees come alive with pollinators to the point that you can literally hear them humming. Though it may not be apparent, the genus Clethra is a distant relative of the heath family. However, taxonomists find it distinct enough to warrant its own family, Clethraceae. Regardless of its taxonomic affinity, this is one tree that needs to find its way into native landscaping. It is such a stunning plant and does well in in both shade and full sun. Few trees are as stunning to come across on a hike than this one and its a species I will look fondly upon for the rest of my life. 

Further Reading:

http://plants.usda.gov/core/profile?symbol=CLAC3

Brother of Hibiscus

Photo by David Eickhoff licensed under CC BY 2.0

Islands are known for their interesting flora and fauna. Until humans came on the scene, colonization events by different species on different islands were probably rare events, with long stretches of time in between. Because of this, islands are interesting experiments in evolution, often having endemic species found nowhere else in the world. Hawai'i was once home to many different kinds of endemic species. One such group are the Hibiscadelphus.

As you may have gathered by the name, Hibiscadelphus is a relative of hibiscus. The Latin name means "brother of Hibiscus." Unlike the widely splayed flowers of their relatives, Hibiscadelphus flowers never fully open. Instead, they form a tubular structure with a curved lower lip. The genus consists of 7 species. Four of these have gone completely extinct, two are only maintained in cultivation, and the remainder is barely holding on. There have been attempts to reestablish some species into other portions of their range but due to hybridization, these attempts were ceased. In my opinion this is a shame. In this case, a hybrid is better than losing both parental species and it would still be uniquely Hawaiian.

Why are Hibiscadelphus so rare? Well, humans have a sad history when it comes to colonizing islands. They bring with them a multitude of invasive species at a rate in which the local flora and fauna cannot adapt. They change the land through cultivation and development as well as by subduing natural fire regimes. Also, they wipe out keystone species, which causes a ripple effect throughout the environment. Hibiscadelphus have faced all of these threats and more. Pigs and rats eat their seeds, their habitats have been turned over for the ever-increasing human population, fires have been stopped, and some of their pollinators, the endemic honeycreepers, have also been driven to extinction thanks to avian pox and malaria. Sadly, this is a story that repeats itself time and time again all over the world. For now, the future of Hibiscadelphus is rather bleak.

Photo Credit: David Eickhoff

Further Reading:

http://bit.ly/2ao84X1

http://bit.ly/2aEfpkn

Yeast in Lichens

Quite possibly one of the oldest symbiotic relationships on Earth has been hiding in plain sight all this time. Lichens have long been regarded as the poster child for symbiotic relationships. Certain species of fungi team up with specific algae and/or cyanobacteria in a sort of "you scratch my back and I'll scratch yours" type of relationship. In return for room and board the photosynthetic partner feeds the fungus. There are many variations on this theme which translates into the myriad shapes and colors of lichen species around the globe. For 150 years we have been operating under the assumption that there is only ever one species of fungus (in the phylum Ascomycota) for any given lichen. We were wrong. 

Originally thought to be contamination, researchers at the University of Montana and Perdue found gene expression belonging to the other major fungal phyla, Basidiomycota. The research team soon realized that they had uncovered something quite monumental. Lichens were harboring a partner we never knew existed. These newly discovered fungi are an entirely new lineage of yeast. What's more, this relationship has been documented in upwards of 52 other lichen genera worldwide! 

This discovery has led to another major breakthrough in lichen biology, their bizarre variety. The exact same species of fungus and alga can produce completely different lichens with wildly different attributes. Take the example of Bryoria torturosa and B. fremontii. They were thought to share the same partners and yet one is yellow and toxic whereas the other is brown and innocuous. Knowing what to look for, however, has revealed that their yeast partners are entirely different. The yeast is thought to be a sort of shield for the lichen, producing noxious acids that deter infections and predation. 

Almost overnight a new light has been shown on our lichen neighbors. These newly discovered partners aren't a recent evolutionary development. This trifecta likely stems back to the early days when little else lived on land. It just goes to show you how much we still do not know about our planet. It's nice to be reminded of this. 

Further Reading:

http://bit.ly/29WWZ2z 

The Cranefly Orchid (Tipularia discolor)

Look closely or you might miss it. Heck, even with close inspection you still run the risk of overlooking it. At this time of year, finding a cranefly orchid (Tipularia discolor) can present a bit of a challenge. At other times of the year the task is a bit easier. If you can find one in bloom, however, you are rewarded with, a unique orchid experience.

For most of the year, the cranefly orchid exists as a single leaf, which is produced in the fall and lasts until spring. It is thought that this orchid takes advantage of the dormancy of its neighbors by sucking up the light the canopy otherwise intercepts during the growing season. Any of you curious enough to look will have noticed that the underside of this leaf is deep purple in color. This very well may be an adaptation to take full advantage of light when it is available. There is some evidence that such coloration may help reflect light back up into the leaf, thus getting more out of what makes it to the forest floor. Evidence for this, however, is limited. It is far more likely that the purple coloration are pigments produced by the leaves that act as a sort of sun screen, shielding the sensitive photosynthetic machinery within from an overdose of sun as intense sun flecks dance across the forest floor.

By the end of spring, the single leaf has senesced. If energy stores were ample that year the plant will then flower. A lanky brown spike erupts from the ground. Its purple-green color is subtle yet beautiful. The flowers themselves are a bit odd, even by orchid standards. Whereas most orchid flowers exhibit satisfying bilateral symmetry, the flowers of the cranefly orchid are distinctly asymmetrical. The dorsal sepal, along with the lateral petals, are scrunched up on either side of the column. This has everything to do with its pollinators.

The cranefly orchid has coopted nocturnal moths in the family Noctuidae for pollination. These moths find the flowers soon after they open and stick around only as long as there is nectar still present in the long nectar spurs. The asymmetry of the bloom causes the pollinia to attach to one of the moth's eyes. In this way the orchid is able to ensure that its pollen is not wasted on the blooms of other species.

As in all plants, the production of flowers is a costly business. Sexual reproduction is all about tradeoffs. It has been found that cranefly orchids that flowered and successfully produced fruit in one year were much less likely to do so in the next. What's more, the overall size of the plant (leaves and corms) were greatly reduced. Its hard to eek out an existence on the forest floor.

What I find most interesting about this species is where it tends to grow. Any old patch of ground simply won't do. Research indicates that the cranefly orchid requires rotting wood as a substrate. It's not so much the wood they require but rather the organisms that are decomposing it. Like all orchids, the cranefly cannot germinate and grow without mycorrhizal associations. They just happen to partner with fungi that also decompose wood. Such a relationship underscores the importance of decaying wood to forest health.

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

Meeting Amborella trichopoda

When I found out I would be seeing a living Amborella, a lump formed in my throat. There I was standing in one of the tropical houses at the Atlanta Botanical Garden trying to keep my cool. No amount of patience was ample enough to quell my excitement. How was I going to react? How big were these plants? Would I see flowers? Could I touch them? What were they growing in? My curiosity was through the roof.

Naturally this sort of excitement is reserved for those of us familiar with Amborella trichopoda. This strange shrub is not something that would readily stand out against a backdrop of tropical flora. However, if life history and ecology were to be translated into outward appearances, Amborella would likely be one of the most gaudy plants on this planet. What I was about the lay eyes on is the only member of the sole genus belonging to the family Amborellaceae, which is the sole member of the order Amborellales.

Even more exciting is its position on the angiosperm family tree. As flowering plants go, Amborella is thought to be the oldest alive today. Okay, so maybe this shrub isn't the oldest flowering plant in the world. It is likely that at one time, many millions of years ago, there were more representatives of Amborellaceae growing on this planet. Until we turn up more fossil evidence it is nearly impossible to say. Still, Amborella's place in the story of flowering plant evolution is consistently located at the base.

That is not to say that this shrub is by any means primitive. I think the first thing that shocked me about these plants is just how "normal" they appear. Sans flowers, I didn't see much out of the ordinary about them. They certainly look like they belong on our timeline. Without proper training in plant anatomy and physiology, there is little one could deduce about their evolutionary position. Regardless of my ignorance on plant morphology, there is plenty to look at on Amborella.

For starters, Amborella has tracheids but no vessel elements, making its vascular system more like that of a gymnosperm than an angiosperm. Its small flowers are borne in the axils of the evergreen leaves. It has no petals, only bracts arranged into a spiral of tepals. The female flowers consist of 4 to 8 free carpels and do not produce a style. Male flowers look like nothing more than a spiral cluster of stamens borne on short filaments.

If plant anatomy isn't enough to convince you, then the genetic analyses tell a much more compelling story. DNA sequencing consistently places Amborella at the base of the flowering plant family tree. Again, this is not to say that this shrub is by any means "primitive" but rather its lineage diverged long before what we would readily recognize as a flowering plant evolved. As such, Amborella offers us a window into the early days of flowering plants. By comparing traits present in more derived angiosperms to those of Amborella, researchers are able to better understand how the most dominant group of plants found their place in this world.

Another interesting thing happened when researchers looked at the DNA of Amborella. What they found was more than just Amborella genes. Inside the mitochondrial DNA are an unprecedented amount of foreign DNA from algae, lichens and mosses. In fact, an entire chunk of DNA corresponded to an entire mitochondrial genome of a moss! Researchers now believe that this is a case of extreme horizontal gene transfer between Amborella and its neighbors both growing on and around it. Both in the wild and in cultivation, Amborella is covered in a sort of "biofilm." Whether or not such gene transfer has assisted in the conservatism of this lineage over time remains to be seen.

At this point you may be asking how this lineage has persisted for over 130 million years. For the most part, it is probably due to chance. However, there is one aspect of its ecology that really stands out in this debate and that is its geographic distribution. Amborella is endemic to Grande Terre, the main island of New Caledonia. This is a very special place for biodiversity.

New Caledonia is a small fragment of the once great super-continent Gondwana. New Caledonia, which was part of Australia at that time, broke away from Gondwana when the super-continent began to break up some 200-180 million years ago. New Caledonia then broke away from Australia some 66 million years ago and has not been connected to another land mass since. A warm, stable climate has allowed some of the most unique flora and fauna to persist for all that time. Amborella is but one of the myriad endemic plants that call New Caledonia home. For instance, 43 species of tropical conifers that grow on these small islands are found nowhere else in the world. The whole region is a refugia of a long lost world.

Being a biodiversity hot spot has not spared New Caledonia from the threats of modern man. Mining, agriculture, urbanization, and climate change are all threatening to undo much of what makes this place so unique. The loss of a species like Amborella would be a serious blow to biodiversity, conservation, and the world as whole. We cannot allow this species to exist only in cultivation. New Caledonia is one place we must desperately try to conserve. Meeting this species has left a mark on me. Being able to observe living Amborella up close and personal is something I will never forget as my chances of seeing this species in the wild are quite slim. I am so happy to know that places like the Atlanta Botanical Garden are committed to understanding and conserving this species both in the wild and in cultivation. For now Amborella is here to stay. Long may it be that way.

Further Reading:

http://bit.ly/29MuMuw

http://bit.ly/29MuML0

http://bit.ly/29ZKNJS

Sequential Ripening

Photo by Nicholas A. Tonelli licensed under CC BY 2.0

There are few things better than hiking on a hot summer day and coming across a big patch of ripe blackberries and/or raspberries. If you're anything like me then you promptly gorge yourself on handfuls of these sweet aggregate fruits. However, the genus Rubus never gives its fruit away all at once. Although this may seem like a pain for us humans, there is good reason for it.

The answer to this ripening strategy lies in the seed dispersers. A multitude of animals feed on the fruit of the genus Rubus but by and large the best seed dispersers are birds. Rubus fruits begin to ripen around the time when many birds are beginning to ramp up their food intake to prep for either migration or the long winter to come. Regardless, birds can travel great distances and thus can spread seeds via their droppings wherever they go.

If Rubus were to ripen their fruit all at once, only a handful of birds would make use of the entire seasons reproductive effort. This means that all the seeds of an individual plant would likely fall to the ground in the general vicinity of the parent. By sequentially ripening their fruit, Rubus ensure that their seeds will not only be available for a few weeks to a couple of months, it also ensures that birds, as well as many other animals, will be involved in the distribution of seeds. It's not just the genus Rubus that does this either. Plenty of other berry producing plants ripen their fruitss sequentially. It is a wonderfully successful strategy to persuade mobile organisms to do exactly what the plants require. 

Photo Credit: Nicholas A. Tonelli (http://bit.ly/1q6Gvja)

Further Reading:
http://bit.ly/29ghcwL

The Mountain Sweet Pitcher Plant

I am fascinated by pitcher plants. The myriad shapes, sizes, and colors make them quite a spectacle. Add to that their carnivorous habit and what is not to love? I am used to having to visit bogs or coastlines to see them in person so you can imagine my surprise to learn that a small handful of pitcher plants haunt the mountains of Southern Appalachia.

Sarracenia jonesii is a recent acquaintance of mine. I never knew this species existed until 2016. It is a slender pitcher plant whose traps grow taller and narrower than the purple pitcher plant (S. purpurea) but not nearly as tall and robust as species like S. leucophylla. Regardless of its size, this one interesting carnivore. One unique aspect of its ecology is the habitats in which it grows. What could be more strange than a pitcher plant clinging to sloping granite slabs?

Most mountainous areas don't hold water for very long. Aside from bowls and the occasional lake, gravity makes short work of standing water. In southern Appalachia, this often results in impressive cascades where sheets of water flow over granite outcrops and balds. Where water moves slow enough to not wash soil and moss away, cataract bogs can form. Soils are so thin in these areas that trees and shrubs can't take root, thus keeping competition to a minimum. Because granite is rather inert, nutrients are scarce. All of these factors combine to make prime carnivorous plant habitat.

A cataract bog clinging to the side of a waterfall.

Along the edges of these cataract bogs, anywhere sphagnum and other mosses grow is where S. jonesii finds a home. One would think that growing in such hard-to-reach places would protect this interesting and unique carnivore. Sadly, that is not the case. To start with, S. jonesii was never common to begin with. Native to a small region of North and South Carolina, it is now only found in about 10 locations. 

Habitat destruction both direct and indirect (alterations in hydrology) has taken its toll on its numbers in the wild. To add insult to injury, poaching has become a serious issue. In fact, an all green population of this species was completely wiped out by greedy collectors looking to add something rare to their collection. The good news is that there are dedicated folks working on conserving and reintroducing this plant into the wild. In 2007, conservationists at Meadowview Biological Research Station, with help from the National Fish and Wildlife Foundation Grant, successfully reintroduced a population of S. jonesii to its former range.

Although the future remains uncertain for this species, it nonetheless has captured hearts and minds alike. Hopefully the charismatic nature of this species is enough to save it from extinction. I only wish such dedicated conservation efforts were directed at more imperiled plant species, both charismatic and not. 

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

On Native Loosestrife and Oil Bees

Oil bees? What the heck are oil bees? Those were my first thoughts when I heard of them for the first time. There are something like 320 species of oil bee in this world, each with their own interesting ecology. These solitary Hymenopterans seek out specific flowers that produce special oils which these bees mix with pollen to feed their developing young. Some even go as far as to use the oils to line their nests. 

Surely these bees must be tropical. I really couldn't imagine this interaction going on up here in the temperate zones. You can imagine my surprise then when I found that there are oil bees and the plants they require haunting some of my favorite hiking spots. As it turns out, some of our native loosestrifes in the genus Lysimachia produce such oils. 

What's more, the bees that utilize them are quite specialized. They all hail from the same genus - Macropis. Female Macropis dig their nests into the ground. Using their highly tuned senses, these solitary bees search far and wide for species of loosestrife that can provide the oils they need. The whorled loosestrife (Lysimachia quadrifolia) is one such species. If you look closely, you can see that the inside of the flowers are streaked with dark resin canals. 

Luckily for the oil bees, this species seems to be quite adaptable as far as habitat goes. I see it most often lining trails and service roads. Mature plants create quite the spectacle with their tall stature, whorled leaves, and sprays of yellow flowers. I will have to pay close attention to these blooms over the next couple of weeks in hopes of seeing the oil bees that share such a close relationship with it. 

Further Reading:
http://bit.ly/28K9k8d

http://bit.ly/28Ks2vV

One Hardy Shrub

One would be hard pressed to find a native shrub with as much adaptability as the dwarf bush honeysuckle (Diervilla lonicera). It is a wide ranging species growing From Saskatchewan to Labrador in Canada all the way down into Georgia. Though it is most often encountered growing on rocky outcrops in the wild, it seems to do equally well under more mesic conditions. It grows rapidly and seems quite fond of suckering. As such, it is an excellent plant for erosion control. 

It is also an important species from an ecological perspective. Many species find this shrub quite appetizing. Its aggressive suckering habitat may be in response to such palatability as it seems to respond to browsing with increased vigor. Its thick growth form is excellent for nesting birds as well as any animal looking for shelter. 

As if cover and browse wasn't enough, the flowers of the dwarf bush honeysuckle are a boon for pollinators far and wide. Flowers range in color from red to yellow and they are accessible enough that many different pollinators benefit from their nectar and pollen rewards. Bumblebees seem to benefit the most from these blooms. It is a real joy to watch a large population of this shrub literally humming with bees. 

Further Reading:

http://bit.ly/29kefyw

http://bit.ly/29iuqac

Meet the Chinkapin Chestnut

I made a new acquaintance this week. While surveying a dry ridge top I began noticing a strange, musty odor in the air. At about the same time I began seeing what looked like spiny chestnut burs littering the ground. I looked above me and there stood the branches of a chestnut in full bloom! 

It didn't make much sense to me that I would be seeing a Chinese chestnut in such a remote high-elevation area. As it turns out, this was indeed a native species of chestnut, though one I have never encountered before. What I was looking at was a healthy stand of Allegheny chinkapin (Castanea pumila). 

The Allegheny chinkapin is a small tree compared to its cousins. It is native to the southeastern United States where it seems to prefer xeric sites. Now I am a child of the post-chestnut era and therefore I am not used to seeing a native chestnut at reproductive age. As it turns out, the Allegheny chinkapin varies in its susceptibility to the chestnut blight that devastated its relatives. 

Reports from Kentucky as well as the Ozark Mountains show that these populations have suffered severely from the blight. Here in North Carolina, however, the situation seems to be a bit better. Trees don't seem to show the signs of heavy infestation (blighted cankers and cracking of the bark), though some trees do show some scarring. Regardless of their susceptibility, it would seem that they are able to reproduce at a smaller size. On top of that, they readily sucker and it doesn't take long for the suckers to mature. 

All in all this is a lovely tree. It is refreshing to know that there is hope for our native Castanea. Its small stature makes for ample opportunity to appreciate this species when you find it. 

Further Reading:

http://bit.ly/29l3XLP

http://bit.ly/29kdSUn

The Ghosts of Florida

Photo by NC Orchid licensed under CC BY-NC 2.0

There are ghosts haunting the Florida Everglades. I'm not talking about the metaphysical kind either. The ghosts I am talking about come in the form of a plant. A strange, mystical, and beautiful plant at that. Growing amongst things like panthers, snakes, palms, ferns, and more mosquitoes than I care to imagine are these rare and endangered plants which have been made famous by court cases, books, and even a Hollywood movie.

If you haven't guessed it by now, I am talking about the ghost orchid (Dendrophylax lindenii). In what is one of Nicolas Cage's best onscreen roles (a close second to Raising Arizona), these orchids were made famous the world over. Based on the book "The Orchid Thief" by Susan Orlean, the movie takes a lot of creative licenses with the story of these orchids.

Ghosts orchids are epiphytes. In Flordia, upwards of 80% of them can be found growing on the bark of pop ash trees (Fraxinus caroliniana). Finding them can be tricky unless you know what to look for. Ghost orchids belong to a group of orchids that have forgone leaf production. No, they are not parasites like Corallorhiza. Instead, they photosynthesize through their long, ambling roots. Pores along their length allow for gas exchange. For most of the year all you will ever see of a ghost is a tangle of roots growing among the moss and lichen on the bark of a tree. 

When a ghost decides to flower, it is easy to see where all the hype comes from. Large white flowers shoot out from the center of the roots, each one with its own twisted pair of tendrils on the lip, which are said to resemble the ghostly outline of a frog jumping through the air. Each flower is also equipped with a long nectar spur. This along with the white coloration and the fact that each flower is most fragrant at night points to the identity of the ghost orchids sole pollinator, the giant sphinx moth. It has a long proboscis that is exactly the length of that nectar spur. No other organism has what it takes to pollinate a ghost. 

The presence of the ghost orchid in southern Florida has everything to do with water. Predominantly a species of the Caribbean, ghost orchids cannot handle frost. In the Everglades, ghosts grow in and around topographical features known as sloughs. Sloughs are ditches that are filled with water for most of the year. Because water has a high specific heat, the sloughs keep the surrounding area cool in the summer and warm in the winter. When Florida experiences hard frosts, these sloughs never get below freezing. This means that these regions are essentially tropical. All these factors combine to make southern Florida the most northerly spot you will ever see a ghost (and many other plant species) growing in the continental United States. 

Sadly, ghost orchids are not doing so hot in the wild. The habitat they rely upon is disappearing at an alarming rate. If you have been to Florida in the last 100 years you can certainly understand. Over half of the Everglades have been drained and developed since 1900 with plenty more of it degraded beyond any hope of repair. Invasive species run amok for the same reasons that the native plants do so well, crowding out some of Florida's most unique flora and fauna. 

To add insult to injury, poaching of ghost orchids is serious business. Despite its difficulty in cultivation and the fact that most wild ghosts quickly die in captivity, there are those out there that will still pay insane prices to have a ghost in their collection. Nursery produced specimens are becoming more common, so with time this should alleviate some of that pressure. Still, there is no end to the senseless greed of some orchid fanatics. 

There is hope on the horizon. Researchers are starting to unlock some of the secret to ghost orchid reproduction. Plants are now being grown from seed in specialized labs. In time, this new generation of ghost orchids will be planted back into southern Florida in hopes of increasing population sizes. 

Further Reading:
http://bit.ly/24NiqT9

http://bit.ly/1XTqh38

http://bit.ly/21jegSg

http://bit.ly/1PZlKJu

In Search of Stewartia

Up until a little over a week ago, I had no idea there were native representatives of the family Theaceae other than Franklinia alatamaha in North America. Dr. Mark Whitten was looking for a tree in order to obtain some genetic samples. He showed me a picture and my jaw just about hit the ground.

Fast forward a few days. A friend sent me an email regarding a hike to see Stewartia in the wild. This was an opportunity I was not about to miss. We took the day off and headed into the mountains. We met up with a small group of people whose goal that day was to bask in the glory of the mountain camellia (Stewartia ovata). We were led by local Stewartia expert, Jack Johnston (http://bit.ly/2908lSY).

It wasn't long before we had our first sighting. Just off the trail leading to a campsite was a spindly looking tree that stood roughly 15 feet in height. Without flowers I don't know if I could pick it out of a lineup. Lucky for us, this small tree was covered in large white blossoms. For the second time that week my jaw had to be pulled up off the ground.

The blossoms were absolutely stunning. About the diameter of a softball and with bright white petals, they are impossible to miss. At the center of each flower is a dense cluster of filaments supporting bright yellow anthers. The filaments themselves are quite attractive. They range in color from pure white to deep purple. What's more, any given tree can sport multiple flowers of with different filament colors.

The color did not seem to influence pollination whatsoever. Each flower we saw was crawling with solitary bees. To be fair though, very little research has been done on this species. Aside from some genetic work, the ecology of the mountain camellia remains a bit of a mystery. What we do know about this tree is that it has its roots in Asia. North America is lucky to have two of the 18 - 20 species of Stewartia. The rest are spread around the Asian continent. North America's Stewartia serve as a reminder of an ancient geologic connection North America and Asia once shared.

By the end of our hike we had lost count of the amount of trees we encountered. Despite their abundance, they are by no means common. Though not technically endangered, their limited distribution and low germination rates make it a sensitive component of the Appalachian flora. With tentative introductions into the horticultural trade, the best way to see this species is in the wild. Look for it growing in cool, shaded edge habitats, most often near mountain streams and rivers. It is a sight you will never forget.

Further Reading:

http://bit.ly/28ZrctJ

http://bit.ly/28ZtA4g

The Endangered Running Buffalo Clover

Endangered species come in all different shapes and sizes. Though the average person on the street can readily cite charismatic animals species such as the giant panda or the white rhino, few folks ever realize that many of the world's plants are at risk of extinction. In fact, the latest reports show that one in five plant species are in danger of disappearing forever. They aren't all charismatic species like orchids either, some of the most endangered plants are often the most ignored. They simply don't find their way into conversations about conservation. 

One prime example of such an imperiled plant is the running buffalo clover (Trifolium stoloniferum). This lovely little clover once ranged from Arkansas, through Illinois and Indiana, all the way to Ohio and West Virginia. It was a species of open disturbed areas in prairies and forests. It enjoyed rich soils and probably followed in the wake of the large herds of bison and regular fires that once shaped the countryside. Another interesting aspect of this clover's ecology is that it apparently does not fix nitrogen. It lacks the rhizobial associates that make legumes famous. 

The loss of the bison from most of its range coupled with rampant habitat destruction spelled disaster for the running buffalo clover. It was thought to be extinct for nearly a century until 1983 when a single population was discovered in West Virginia. Since then scattered populations have been found, however, these are few and far between. As such, it is now considered a federally endangered species. 

The continued survival of the running buffalo clover is completely tied to proper land management. Without a natural disturbance regime, this lovely little plant is quickly overtaken by more aggressive vegetation. Gone are the days of the roaming buffalo and natural fire regimes. 

Luckily this species was able to garnish enough attention to earn it some protection. However, for far too many plant species this is simply not the case. Until we change the kinds of conversations we are having about plants and habitat in general, we stand to lose more plant species than I care to imagine. This in turn will have rippling effects through the entire ecosystem. So, today I want you to think about the running buffalo clover as a stark reminder of just how important conservation can be. 

Photo Credit: Andrew Lane Gibson (http://bit.ly/25Sb6f1)

Further Reading:
http://1.usa.gov/1sB7oo9

Buffalonut - A Parasitic Shrub From Appalachia

I have a hard time with shrubby species. They just don't stand out to me like herbaceous plants or giant trees. As such, my identification skills for this group of medium-sized woody plants are subpar. However, every once in a while I find something that I can't let go. Usually its a species with a trait that really stands out. This is how I came to know buffalo nut (Pyrularia pubera). Its unique inflorescence was like nothing I had ever encountered before. 

There is good reason for my unfamiliarity with this species. It is largely restricted to the core of the Appalachian Mountains, although there are records of it growing on Long Island as well. Regardless, it is not a species I grew up around. The first time I saw its flowers I was stumped. I simply couldn't place it. Luckily its unique appearance made it easy to track down. I was happy with buffalo nut for the time being but I was surprised yet again when I sat down for a chat with someone who knows woody species much better than I do. 

As it turns out, buffalo nut belongs to the sandalwood family, Santalaceae. This makes it a distant cousin of the mistletoes. Like most members of this family, buffalo nut lives a parasitic lifestyle. Although it is fully capable of photosynthesis and "normal" root behavior, under natural conditions, it parasitizes the roots of other tree species. It doesn't really seem to have a preference either. Over 60 different species hailing from 31 different families have been recorded as hosts. 

When a buffalo nut seed germinates, it starts by throwing down a taproot. Once the taproot reaches a certain depth, lateral roots are sent out in search of a host. These roots "sniff out" the roots of other species by honing in on root exudates. When a suitable root is found, the buffalo nut root will tap into its host using specialized cells called haustoria. Once connected, it begins stealing water and nutrients. Buffalo nut roots have been known to travel distances of 40 feet in search of a host, which is pretty incredible if you ask me. 

It is easy to look down on parasites. Heck, they are largely maligned as free loaders. This could not be farther from the truth. Parasites are a healthy component of every ecosystem on the planet. They are a yet another player in a system that is constantly changing. What's more, the presence of parasites can actually increase biodiversity in a system by keeping certain species from becoming too dominant. Buffalo nut should not be persecuted. Instead it should be celebrated. It is yet another species that makes the Appalachian Mountain flora so unique. 

Further Reading: [1] [2]

Sweetshrub

It's hard to be in a bad mood when there are sweetshrubs (Calycanthus floridus) in bloom. This wonderful native shrub is both easy on the eyes and the nose. In some parts of its range, it is affectionately referred to as Carolina allspice. It has been placed in the family Calycanthaceae, which it shares with other genera such as Idiospermum of Australia and Chimonanthus of Asia. This family is actually quite old. Genetic analysis coupled with fossil evidence suggests that the common ancestors of this group began diverging at some point during the Cretaceous, some 97 million years ago.

Sweetshrub is predominantly native to southeastern North America, though it can be found growing naturally as far north as the Virginias, though it seems to be expanding its range both north and west. It is quite an adaptable species when it comes to habitat but it seems to do best on rich loam in partially shaded conditions. Sweetshrub suckers readily and a small patch can quickly spread to cover a much larger area.

By far my favorite aspect of this shrub are its flowers. They don't produce any sepals or petals but instead put forth spirals of leathery tepals that open gradually as the flowers mature. Flower color is most often a deep shade of burgundy, however, orange and green flowers have been recorded as well. I usually smell them before I see them. To me, the flowers smell like sweet fermenting apples. Their main pollinators are sap beetles and it is not uncommon to find them crawling all over the blooms. I also frequently see fruit flies going about their business on these shrubs, undoubtedly attracted by the scent as well.

It's not just the flowers that smell either. The whole plant is rather aromatic. Scrape the bark and you may smell something akin to camphor. Crushed leaves smell sweet and spicy. However, the strength of these odors can vary greatly from plant to plant and may have a lot to do with its growing conditions. All in all this is one incredible species. Its adaptability, lack of pests, and pleasing appearance/fragrance have made this a popular shrub for native landscaping in the southeast.

Further Reading: [1] [2]

Fern Ant Farm

Photo by Ch'ien C. Lee (www.wildborneo.com.my/photo.php?f=cld1505721.jpg)

An epiphytic lifestyle is no walk in the park. Baking sun, drying winds, and a lack of soil are the norm. As a result, epiphytic plants exhibit numerous adaptations for retaining water and obtaining nutrients. One of the most interesting adaptations to this lifestyle can be seen in plants that have struck up a relationship with ants.

An amazing example of one such relationship can be seen in a genus of epiphytic ferns called Lecanopteris. Native to Southeast Asia and New Guinea, their unique look is equally matched by their unique ecology. Using a highly modified rhizome, they are able to latch on to the branch of a tree. In species such as Lecanopteris mirabilis (pictured above), it's as if the fronds are emerging from a strange green amoeba.

However, it's whats going on underneath their strange rhizomes that makes this group so fascinating. These ferns literally grow ant farms. Chambers and middens within the amorphous rhizome entice colonies of ants to set up shop. In return for lodging, the ants provide protection. Anything looking to take a bite out of a frond must contend with an army of angry ants. Moreover, the ants provide valuable nutrients in the form of waste and other detritus.

These are by no means the only plants to have evolved a relationship of this sort. Myriad plant species utilize ants for protection, nutrient acquisition, and seed dispersal. It has even been suggested that the unique morphology of Lecanopteris spores is an adaptation for ant dispersal. Certainly one can imagine how that would come into play. Interestingly enough, this group of ferns has attracted the attention of plant enthusiasts looking for a unique plant to grow in their home. As such, you can now find many different species of Lecanopteris being cultivated for the horticultural trade.

Photo Credit: Ch'ien C. Lee (www.wildborneo.com.my/photo.php?f=cld1505721.jpg)

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

"The Ghosts of Cultivation Past"

Photograph © Andrew Dunn, 13 September 2005. Website: http://www.andrewdunnphoto.com/ licensed under CC BY-SA 2.0

All too often we think of a species' niche as a sort of address. Species will be present in suitable habitat and absent from unsuitable habitat. Certainly this oversimplification has been useful to us, however, it often ignores context. Species, especially long lived ones, can often be found in unsuitable habitat. Similarly, biotic interactions such as pollinators and seed dispersers are regularly overlooked when considering "suitable habitat." The absence of factors such as this can leave plants stranded in suboptimal conditions. 

A recent paper published in PLOS One tackles this very idea by looking at a species of tree many of us will be familiar with - the honey locust (Gleditsia triacanthos). This central North American legume is widely planted as a street/landscape tree all over the United States. Ecologically speaking, honey locusts can be found growing wild in open xeric upland sites. In places like the southern Appalachian Mountains, however, they can also be found growing in mesic bottomlands. Regardless of where it is found, the honey locust seems to be severely dispersal limited (except in cases where cattle and other livestock have been introduced). 

Before modern times, honey locust likely relied on Pleistocene megafauna to get around. The end of the Pleistocene marked the end of these large mammals. Left behind were many different plant species that had evolved alongside them. For a small handful of these plants, humans were a saving grace. Such is the case for the honey locust. Inside the honey locust pods there is a sugary pulp, which in southern Appalachia, the Cherokee were quite fond of. The Cherokee also used the tree for making weapons and gamesticks. As such, the honey locust holds great cultural significance, so much so that the Cherokee named at least one settlement "Kulsetsiyi" (more commonly known today as Cullasaja), which translates to "honey locust place." 

Author, Dr. Robert Warren, noticed that in southern Appalachia, "Every time I saw a honey locust, I could throw a rock and hit an archaeological site.” What's more, the trees were not recruiting well unless cattle or some other form of human disturbance was present. This species seemed to be a prime candidate for testing persistent legacy effects in tree distributions. 

Using seed germination experiments and lots of mapping, Dr. Warren was able to demonstrate that honey locust distributions in the southern Appalachian region are more closely tied to Cherokee settlements than its own niche requirements. The germination experiments strengthened this correlation by showing that mesic bottomlands had the lowest germination and survival rates. 

Additionally, these sites are well known as former sites of Cherokee settlement and agriculture. Because this tree held such significance to their culture, it is quite likely that in lieu of Pleistocene megafauna, Native Americans, and eventually European livestock, allowed the honey locust to reclaim some of its former glory. Of course, today it is a staple of horticulture. Still, the point is that despite being found growing in a variety of habitat types, the honey locust is very often found in unsuitable habitat where it cannot reproduce without a helping hand. In the southern Appalachian region, honey locust distributions are more a reflection of Native American cultural practices.

Photo Credit: Cambridge Botanic Garden

Further Reading:
http://bit.ly/27SySpq

The Magnificent Mountain Laurel

Mountainsides awash with blooming mountain laurel (Kalmia latifolia) are truly a spectacle. Seeing a sea of pinks, whites, and greens humming with pollinators makes you wonder why such a sight isn't talked about more outside of its range. Why hoards of tourists don't time their seasonal migrations around the blooming of this species is, to me, quite a mystery.

Mountain laurel was a shrub I was quite familiar with growing up. As a child, their shaded tunnel-like understory were some of my favorite places to explore and catch bugs. After moving to New York, I soon forgot about this shrub. Other species became my familiar backdrop. It took visiting the mountains of North Carolina to reawaken these long forgotten memories.

Mountain laurel is generally considered a shrub. In wet, humid areas in the Appalachians, they can readily reach a stature more fitting of a small tree. They are evergreen, holding on to their beautiful leaves throughout the winter. This helps save energy, which is especially useful in poor soils. It also allows mountain laurel to get a head start on photosynthesis as soon as temperatures become favorable.

My favorite part of this shrub are its flowers. Deep pink textured buds soon give way to a floral display that will knock your socks off. Each flower ranges in color from white to pink. Each bloom demands a closer inspection. They are ringed in tiny pockets, each housing an anther. As the flower opens, the pockets hold on to the anthers, drawing them tight. When an insect, especially a bee, disrupts the pockets, the anthers spring out of the pockets and bash the insect with pollen. Each visit is like stumbling into a army of tiny pollen-laden trebuchets. This can easily be simulated using a small stick.

Further Reading:
http://bit.ly/25eAwzI

The Aposematic Gall Hypothesis

Maple eyespot gall (left) and the grape tumid gall (right)

If you spend any time around plants you will have undoubtedly come across a gall. In fact, once you know what to look for you quickly realize that galls are everywhere. They come in many different shapes and sizes and they vary as much as the species you will find them on. Galls are abnormal growths on plant tissues and their causes range from bacteria, fungi, and nematodes to insects and mites. Most of the galls we regularly encounter are caused by insects. 

You can think of galls as a type of edible nursery chamber. A female insect will lay her eggs in the tissue of the plant and chemicals released by the eggs and subsequently the developing larvae trigger abnormal tissue growth in the plant. Every detail of each gall you see is the result of the insect housed inside, which has led some authors to consider gall formation a literal extension of the insect phenotype. Without the chemicals released by the developing insects, the plant would not form such elaborate growths.

Lime nail gall (Eriophyes tiliae). Public Domain.

As mentioned, galls act as an edible nursery chamber. Not only does the developing larvae gain physical protection, they also consume the swollen plant tissues on the inside of the gall. Despite the attention galls have received in the literature, very few studies have touched on one fact of gall ecology that becomes quite obvious to the casual observer - most of them are very conspicuous.

Oak apple gall (Cynipidae). Public domain.

The shape and coloration of different kinds of gall causes them to really stand out against the background vegetation. Why would a structure meant to protect the developing insect inside be so easy to spot? A handful of interesting hypotheses have been put forth to explain this phenomenon. For starters, the chemical compounds that give many galls their distinctive coloration are the result of hijacked plant pigments such as carotenoids, anthocyanins, as well as tannins and other phenolic compounds. These are thought to protect the insect inside. This certainly plays a role, but we will come back to that in a minute.

Cynipid gall (Diplolepis polita). Photo by Dean Morley licensed under CC BY-ND 2.0

Still, one would think being so strikingly obvious would have some serious drawbacks. Predators and parasitoids alike could easily hunt down a bright red gall. Even if potential predators can't see color, the outlandish shape of many galls certainly makes them stand out. There is another hypothesis that gets right to the core of this. Simply put, it is thought that the conspicuousness of galls serves as a warning to potential predators that eating them would be a mistake. In other words, galls very well may be aposematic. 

You will be most familiar with aposematic coloring in bees and wasps. Bright colors such as red or yellow contrasted against a strikingly different colored background serve as a warning to anything that might be thinking of taking a bite. "Stay away, I will hurt you" is the gist of the message. The bright coloration and often outlandish shape of galls coupled with the defensive compounds mentioned above may be sending a signal to herbivores, predators, and parasites to stay away or risk injury or illness. Being easy to find also makes galls easier to remember and a bad experience with one gall may make a bird think twice before messing with one again. In this way, the insects inside can go unmolested until it matures. 

Obviously there are many caveats to this idea. Certainly not all galls fall under this umbrella. The researchers behind this hypothesis have outlined a series of predictions that are thought to promote the evolution of aposematism as a strategy. What's more, this hypothesis will need to be tested on many different types of galls in many different habitats with many different potential predators if it is to hold up. Still, it is an interesting idea worth investigating. One can see the potential here. 
 

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

Further Reading: [1]