The Grasstree of Southwestern Australia

Taken by John O'Neill licensed under CC BY-SA 3.0

Southwestern Australia is home to a wonderful and unique flora. A combination of highly diverse, nutrient-poor soil types, bush fires, and lots of time have led to amazing adaptive radiations, the result of which are myriad plant species found nowhere else in the world. One of the most incredible members of southwestern Australia's flora is the grassplant (Kingia australis). Like all plants of this region, it is one hardy species.

The taxonomic history of the grassplant has been a bit muddled. As its common name suggests, it was once thought to be a type of grasstree (genus Xanthorrhoea), however, its resemblance to this group is entirely superficial. It has since been placed in the family Dasypogonaceae. Along with three other genera, this entire family is endemic to Australia. Growing in southwestern Australia presents lots of challenges such as obtaining enough water and nutrients to survive and for the grassplant, these have been overcome in some fascinating ways.

The way in which the grassplant manages this is incredible. Its trunk is not really a true trunk but rather a dense cluster of old leaf bases. Within this pseudotrunk, the grassplant grows a series of fine roots. Research has shown this to be an adaptation to life in a harsh climate. Because water can be scarce and nutrients are in short supply, the grassplant doesn't take any chances. Water hitting the trunk is rapidly absorbed by these roots as are any nutrients that come in the form of things like bird droppings.

Photo by Casliber licensed under CC BY-SA 3.0

Coupled with its underground roots, the grassplant is able to eek out a living in this dry and impoverished landscape. That being said, its life is spent in the slow lane. Plants are very slow growing and estimates place some of the larger individuals at over 600 years in age. Its amazing how some of the harshest environments can produce some of the longest lived organisms.

As you can probably imagine, reproduction in this species can also be a bit of a challenge. Every so often, flower clusters are produced atop long, curved stems. Their production is stimulated by fire but even then, with nutrients in poor supply, it is not a frequent event. Some plants have been growing for over 200 years without ever producing flowers. This lifestyle makes the grassplant sensitive to disturbance. Recruitment is limited, even in good flowering years and plants take a long time to mature. That is why conservation of their habitat is of utmost importance.

Photo Credits: [1] [2]

Further Reading: [1] [2]

Arums, Orchids and Vines, Oh My!

This week we head into the forests of Illinois to see what late spring botany we can find. This is one of the coolest times of the year to look for plants in temperate North America. 

Producer, Writer, Creator, Host:
Matt Candeias (http://www.indefenseofplants.com)

Producer, Editor, Camera:
Grant Czadzeck (http://www.grantczadzeck.com)

Twitter: @indfnsofplnts

Facebook: http://www.facebook.com/indefenseofplants

Patreon: http://www.patreon.com/indefenseofplants

Tumblr: http://www.tumblr.com/indefenseofplants
_________________________________________________________________

Music by: 
Artist: Lazy Legs
Track: Molasses
Album: Lazy Legs EP
http://lazylegs.bandcamp.com

Wet Prairies and the White Lady's Slipper

This week we visit a wet prairie in search of the white lady's slipper orchid (Cypripedium candidum). This is a unique habitat type full of incredible plants and we meet many of them along the way. Special thanks to Paul Marcum (http://bit.ly/2r6SG8s) in making this episode possible! 

If you would like to support orchid conservation efforts here in North America, consider purchasing a stick over at http://www.indefenseofplants.com/shop/

Producer, Writer, Creator, Host:
Matt Candeias (http://www.indefenseofplants.com)

Producer, Editor, Camera:
Grant Czadzeck (http://www.grantczadzeck.com)

Twitter: @indfnsofplnts

Facebook: http://www.facebook.com/indefenseofpl...

Patreon: http://www.patreon.com/indefenseofplants

Tumblr: http://www.tumblr.com/indefenseofplants

_________________________________________________________________

Music by: 
Artist: Lazy Legs
Track: Chain of Pink
Album: Chain of Pink
http://lazylegs.bandcamp.com

Exploring a Sand Prairie

In this exciting episode, In Defense of Plants explores the fascinating botanical communities growing in a sand prairie in central Illinois. The unique soil conditions makes this place a hotbed for rare plants. Many of these species are disjuncts from further west. 

The story of this place began some 14,000 years ago as glacial outwash from the long gone Lake Chicago blew across the landscape and piled into great sand dunes. Join us for a fascinatingly beautiful botanical adventure. 

CORRECTION: The cactus is not Optuntia fragilis, it is actually the eastern prickly pear (Opuntia humifusa)... Woops!

Producer, Writer, Creator, Host:
Matt Candeias (http://www.indefenseofplants.com)

Producer, Editor, Camera:
Grant Czadzeck (http://www.grantczadzeck.com)

Facebook: http://www.facebook.com/indefenseofpl...

Patreon: http://www.patreon.com/indefenseofplants

Tumblr: http://www.tumblr.com/indefenseofplants

Twitter: @indfnsofplnts
_________________________________________________________________

Music by: 
Artist: Lazy Legs
Track: Sparks
Album: VISIONDEATH
http://lazylegs.bandcamp.com

The Shrubs of Iridaceae

Nivenia corymbosa

Did you know there are shrubs in the iris family? I didn't either until quite recently. I had the distinct honor of getting to tour the collections of Martin Grantham, a resident of the Bay Area and quite possibly the most talented horticulturist I have ever met. Martin has had quite a bit of luck with these plants and because of this, I was able to meet a handful of them growing quite happily in large containers. There are some things in life that your brain just simply isn't prepared to take in. The shrubby iriads are one of them.

The true shrubby species all hail from a subfamily of Iridaceae coined Nivenioideae. This is not a single grouping of all shrubby genera. It contains other genera that look a lot more like what we would consider an iris. Nivenioideae as a whole is considered to be pretty derived for the iris family, with the shrubby species serving as an excellent example of how bizarrely unique the subfamily really is. In total, there are three genera of shrubby iriads - Klattia, Nivenia, and Witsenia, all of which are native to South Africa. Klattia and Nivenia contain a small handful of species whereas Witsenia has only a single representative.

Once you get past the initial shock and awe of what you have just laid eyes on, their membership in the iris family becomes a bit more apparent. Though there is great variation in size, the species I encountered all looked roughly like long, slender sticks with multiple iris-like fans of leaves jutting out. Like most members of the family, the flowers of this group are spectacular. In the wild they are visited by long tongue bees and flies.

Overall this group is poorly understood. Some molecular phylogenetic work has been performed but it is by no means concrete. More attention may result in either the addition or subtraction of species. The most thorough treatment on the shrubby iriads comes from a monograph written by Dr. Peter Goldblatt as well as a handful of horticultural articles written by those lucky enough to have had some success in growing these plants (see Martin's essay on his experiences - http://bit.ly/2pStMZ4).

Like most of South Africa's unique flora, these plants are at threatened by habitat destruction, invasive species, and climate change. Luckily many of these species have caught the attention of folks like Martin who have put in the time and dedication into understanding their germination and growth requirements.

Seeing these plants in person was breathtaking. Not only was I completely flabbergasted at their appearance, the fact that plants like this exist is a testament to the wild diversity of life this planet supports. I never tire of meeting new plant species and this is one encounter I won't soon forget. Just when you think you are starting to understand plant diversity, plants like these show up to remind you that you have just barely scratched the surface.

Further Reading: [1] [2]

Meet the Redbuds

I look forward to the blooming of the redbuds (Cercis spp.) every spring. They paint entire swaths of forest and roadside with a gentle pink haze. It’s this beauty that has led to their popularity as an ornamental tree in many temperate landscapes. Aside from their appeal as a specimen tree, their evolutionary history and ecology is quite fascinating. What follows is a brief introduction to this wonderful genus.

The redbuds belong to the genus Cercis, which resides in the legume family (Fabaceae). In total, there are about 10 species disjunctly distributed between eastern and western North America, southern Europe, and eastern Asia. The present day distribution of this genus is the result of vicariance or the geographic separation of a once continuous distribution. At one point in Earth’s history, the genus Cercis ranged from Eurasia to North America thanks to land bridges that once connected these continents. At some point during the Miocene, this continuous distribution began to break apart. As the climate changed, various Cercis began to diverge from one another, resulting in the range of species we know and love today.

All of them are relatively small trees with beautiful pink flowers. Interestingly enough, unlike the vast majority of leguminous species, redbuds are not known to form root nodules and therefore do not form symbiotic relationships with nitrogen-fixing bacteria called rhizobia. This might have something to do with their preference for rich, forest soils. With plenty of nitrogen available, why waste energy growing nodules? Until more work is done on the subject, its hard to say for sure why they don’t bother with nitrogen fixers.

One of the most interesting aspects of the redbuds are their flowers. We have already established that they are very beautiful but their development makes them even more interesting. You have probably noticed that they are not borne on the tips of branches as is the case in many flowering tree species. Instead, they arise directly from the trunks and branches. This is called "cauliflory," which literally translates to "stem-flower." In older specimens, the trunks and branches become riddled with bumps from years of flower and seed production.

It's difficult to make generalizations about this flowering strategy. What we do know is that it is most common in dense tropical forests. Some have suggests that producing flowers on trunks and stems makes them more available to small insects or other pollinators that are more common in forest understories. Others have suggested that it may have more to do with seed dispersal than pollination. Regardless of any potential fitness advantages cauliflory may incur, the appearance of a redbud covered in clusters of bright pink flowers is truly a sight to behold.

Further Reading: [1] [2] [3] [4] [5] [6] [7]

Meet Virginia Pennywort

Meet the pennywort gentian (Obolaria virginica). It is a plant of the southeast with its most northerly distribution being around Pennsylvania. I am a little obsessed with gentians so finding this plant is always a special treat. My first encounter left me a bit perplexed by its overall appearance, which is very compact. The leaves and flowers all seemed to be mashed together, competing for space. 

Its small stature and dark coloration cause it to blend in surprisingly well with the forest floor. You often don't see it until you are right on top of one. Something seems to be working well for the Virginia pennywort because once you find one, you usually find many more. Oddly enough, I most frequently see this species in its highest abundance on the side of well-trafficked trails. Add to that its highly reduced leaf area and you have a few traits that usually get me thinking about parasitic plants. Anecdotally speaking, I often find parasitic plants growing near foot traffic. If I had to guess, I would say that it has something to do with root damage, however, I have no data to support such claims. That being said, the literature suggests I wasn't wrong in my suspicions.  

The roots of the Virginia pennywort are described as "coralloid", meaning they take on a structure reminiscent of some corals. This is usually a trait exhibited by species whose roots are closely associated with microbes such as cyanobacteria or certain fungi. Indeed, the roots of the Virginia pennywort are often infested with arbuscular mycorrhizae. Additionally, there is some molecular evidence to suggest that this species is at least partially mycoheterotrophic, meaning it gets some at least some of its nutrients parasitically from said mycorrhizal fungi. Isotope analysis demonstrated that the tissues of the Virginia pennywort were more enriched with isotopes of carbon than the surrounding vegetation.

It is a really neat plant to find. If you do, make sure to take some time with it and get down on its level for a closer look. You won't be disappointed!

Further Reading:
http://www.amjbot.org/content/97/8/1272.short

http://plants.usda.gov/java/profile?symbol=obvi

Early Spring Botanizing

SURPRISE!

Many have commented that a video component was lacking from the hiking podcasts. I have teamed up with filmmaker/producer Grant Czadzeck (www.grantczadzeck.com) to bring you a visual botanizing experience. I'm not sure how regular this will become but let us know what you think. In the mean time, please enjoy this early spring hike in central Illinois.

Carnations Revealed

Photo by Zeynel Cebeci licensed under CC BY-SA 3.0

Confession: over-bred, multi-petaled carnations make me want to puke. I find them monstrously gaudy. I don't like feeling this way towards a plant. It isn't the plants fault that we turned it into such a mutant. So, today I though I would dedicate this space to honoring the wild congener of the domestic carnation.

When we talk about carnations we are referring to cultivars of the genus Dianthus. The most prominent cultivars we see today originated from Dianthus caryophyllus. It is hard to pinpoint the native origin of this species as it has been cultivated throughout Europe and Asia for upwards of 2000 years. Regardless, it is thought that the wild carnation is native to a stretch of the Mediterranean region encompassing Greece and Italy.

Wild carnations are more sleek in appearance than their cultivated cousins. They are modest sized plants each producing flowers with five serrated petals that range in color from white to pink. The flowers are protandrous meaning the male parts mature and senesce before the female parts. This helps to reduce inbreeding. Nectaries are located at the base of the flower and it is thought that long tongued bees and lepidotera take up the bulk of pollination services.

Following pollination, the petals begin to produce ethylene gas. This causes near complete collapse of the flowers within 24 hours. Why bother wasting energy on expensive floral parts that can now be directed to seed production? Upon maturity, the seed capsule breaks open at the top. Its position at the tip of the stem allows for a combination of ballistic and wind seed dispersal. As the capsule sways back and forth in the breeze, the tiny seeds are launched from the capsule like shrapnel from a catapult.

The multi-petaled mutants we have selectively bred barely function as viable plants anymore. In the wild, carnations are perennial, producing one to six flowers a season and plenty of seeds. Because we value looks and longevity over biology, cultivated carnations will often flower themselves to death in one season. Also, the duplication of petals has made it so that insects cannot reach the interior to get at the pollen or nectar, removing a great deal of their potential ecological value.

Dianthus caryophyllus isn't alone in this genus. Over 300 species of Dianthus have been described each with their own ecology and distribution. They range in appearance from modesty creeping herbs to woody shrub-like plants. Many of these have been utilized by plant breeders to create new cultivars. Unfortunately this is yet another genus of plants whose cultivars get all the attention.

Photo Credit: [1]

Further Reading: [1] [2]

Mayaca!

When I first saw this little plant growing along the boarders of a pond, I thought I was seeing a semiaquatic Lycopod. Was I ever wrong. It turns out I was looking at an angiosperm commonly encountered by aquarium enthusiasts - Mayaca fluviatilis. The genus Mayaca has its own family (Mayacaceae) and its members can be found throughout Southeastern North America, Latin America, the West Indies, and central Africa. It was very exciting to meet one of these plants in person!

The Lowly Lawn Orchid

A new year and a new orchid. It didn't take long for me to spot this little plant poking up between the succulent leaves of a potted aloe. My elation was short lived though. Alas, the sun was setting and I didn't have a flashlight or my camera. I was much luckier the next day. Actually, I shouldn't say lucky. This orchid isn't uncommon.

Meet the lawn orchid (Zeuxine strateumatica). Originally native to Asia, this species is expanding its range throughout many parts of the globe. Here in Florida, it was first discovered in 1936. There was a bit of confusion surrounding its origin on this continent, however, it is now believed that seeds arrived in a shipment of centipede-grass from China.

Since its premiere in Florida, the lawn orchid has since spread to Georgia, Alabama, and Texas. It seems to be quite tenacious, growing equally as well in lawns, floodplains, forests, meadows, and even sidewalk cracks! Despite this generalist habit, it does not seem to transplant well and is probably quite specific about its mycorrhizal partner. Much work needs to be done to sleuth out exactly why this little orchid has been able to spread so far outside of its native range.

Though small flies will visit the flowers, it is very likely that this orchid mostly self pollinates. It doesn't take long to flower and set seed. One plant can easily result in hundreds if not thousands of seedlings. After setting seed, the parent plant dies, however, it will often bud off new plantlets from its roots. Its ubiquitous nature can often stand in contrast to its ability to disappear for a series of time. Large stands that appear one year may not return for many years after. Still, in some areas this little orchid is abundant enough to be considered a nuisance.

Despite whatever feelings you may have towards this little plant, I nonetheless admire it. Its not often you find orchids so adaptable to a wide variety of conditions. At the very least it offers us insights into the success of plant invasions around the globe. And, in the end, its a nice looking little plant.

Further Reading: [1] [2]

A Cave Dwelling Nettle From China

Photo by Monro & Wei [SOURCE]

Caves and plants do not seem like a good combo. Plants need sunlight and caves offer very little to none of it. However, plants in general never seem to read the literature we write about them. As such, they are constantly surprising botanists all over the world. 

A recent example of this was published back in September of 2012. A team of botanists exploring limestone gorges in southwestern China stumbled upon three new members of the nettle family. One of these nettles seemed to be right at home growing well within two limestone caves. 

Needless to say this was quite a shock to the botanists. The regions in which these plants were growing were quite dim, with light levels ranging from a mere 0.04% to a measly 2.78 % of full daylight! Although this is by no means complete darkness, it is an incredibly low amount of sunlight for a plant that still relies on photosynthesis to get by. 

They named the nettle Pilea cavernicola in reference to its cave-dwelling habit. While it has only just been discovered, the IUCN considers this species vulnerable. Only two populations are known and their proximity to expanding human activity puts them in danger of rapid extinction. 

Photo Credit: Monro & Wei

Further Reading: [1]

The Fuzziest of Flowers

Photo by Andreas Kay licensed under CC BY-NC-SA 2.0

Describing plants can be quite a task for taxonomists. When a new species is discovered, the honor of naming it often goes to the discoverer. At the very least, they have some input. Some folks go for the more traditional rout and give the plant a descriptive name rooted in either Latin or Greek. Others decide to name the plant in honor of a botanist of the past or perhaps a loved one. Still others take a stranger approach in order to immortalize a famous celebrity. However, in doing so they risk taking something away from the species in question.

Instead of a descriptive name that clues you in on specific features of the plant, instead you hit an etymological dead end in which you are stuck with nothing more than a last name. This became quite apparent to University of Alabama botanist John Clark when it was time to name a newly discovered plant species from South America. 

Had things been slightly different, the recently discovered Kohleria hypertrichosa would have been named after Chewbacca. One look at the flowers of this species and you can understand why. The long tubular petals of this gesneriad are covered in dense, fuzzy hair. This is unlike any other plant known to science. The appearance of these odd fuzz balls may seem puzzling at first but considering where this plant was found growing, it quickly becomes apparent that these flowers are a marvelous adaptation in response to climate. 

Kohleria hypertrichosa is only known to grow in a very narrow swath of mountainous cloud forest in the Ecuadorian Andes. At home between elevations of 3,600 and 6,600 feet above sea level, this wonderful gesneriad experiences some pretty low temperatures for a tropical region. It is likely that the thick layer of hairs keeps the flowers a bit warmer than the surrounding air, offering a welcoming microclimate for pollinators. This could potentially make them much more likely to be pollinated in a habitat where pollinators may be in short supply. 

At the end of the day, Clark decided to stick with a more traditional name for this new species. Its scientific name is no less interesting as a result. The specific epithet 'hypertrichosa' is derived from a condition in humans known as hypertrichosis, or werewolf syndrome, in which a person grows excessive amounts of body hair. 

Photo Credit: Andreas Kay [1]

Further Reading: [1]

Wasabi

Photo by Qwert1234 licensed under CC BY-SA 3.0

Whether you like wasabi or hate it, there is a very high probability that you have never actually tasted it. It is estimated that only about 5% of Japanese restaurants around the world actually offer the real stuff. Instead, the wasabi we most often indulge in is a mix of mustard, European horseradish (Armoracia rusticana), and green food coloring. This begs the question, why is real wasabi so hard to come by?

The answer to this lies in the plant. Real wasabi comes from a species of mustard native to the mountains of Japan. Flowering for this group consists of an inflorescence packed with small, white, 4-petaled flowers shoots up above the leaves. There exists two species within the genus - the uncultivated Wasabia tenuis and the cultivated Wasabia japonica. It has been suggested that these plants be moved out of the genus Wasabia and into the genus Eutrema. Regardless of their taxonomic affiliation, these are beautiful and interesting plants. 

Whereas W. tenuis tends to grow on mesic mountainsides, W. japonica prefers to grow in and around streams. In fact, it can often be found growing right out of the gravelly stream bed. Its strict riparian habit has made it hard for this plant to catch on commercially. Although it doesn't grow submerged like an aquatic plant, it nonetheless needs running water. Without it, the plant will languish and die. Although methods of soil growing W. japonica are sometimes used, these are very labor intensive and require a lot of inputs in order for the plants to thrive. The plant also seems to be highly susceptible to disease if planted in high densities. Overall this has made finding real wasabi a difficult, and not to mention expensive, venture. 

Photo Credit: Qwert1234 (Wikimedia Commons)

Further Reading: [1]

Plants and Music

Turn up the music! My plants can't hear it! Okay, there goes a cheap attempt at humor... In all seriousness, I was always told as a child that plants respond to music. I have since heard many variations on the theme but basically the ideas is that plants, when exposed to music, respond with increased growth. To take things one step further, it would seem that plants have something akin to musical tastes, preferring classical to rock music.

Is there any real scientific evidence to this or is it all just a bunch of silly pseudoscience? Also, if it is true, what could possibly be going on within the plant that causes a response to music, something we thought was reserved to lifeforms with the proper sensory equipment?

The truth is, there is not much real science to base these assumptions on. The internet is full of anecdotal tales and "experiments" that hinge themselves on new age belief systems. In fact, the first "experiments" on how music influences plant growth was done by a woman named Dorothy Retallack. 

Retallack claimed that plants exposed to classical music grew vigorously whereas plants exposed to rock music languished. Considering how much heavy metal my houseplants are exposed to, I think I have more than enough evidence to say otherwise. Besides her poor experimental design, Retallack was heavily motived by quite a conservative, religious agenda. She had it out for mean old rock n' roll and was damned if she couldn't prove her point. What work has been done since Rettalack's time is tantalizing at best but from this point on, keep in mind that the jury is still out on this topic.

So, why would plants respond to music? They don't have ears or anything in their biology that would function as an auditory device, right? Let's re-frame the question in a more basic sense. What is music? Music is nothing more than organized sounds and sounds are nothing more than pressure waves, that is, disturbances in the atmosphere, a process akin to wind. Plants do, in fact, respond to wind, however, wind is a far more physical force than music. Wind can blow over entire swaths of forest whereas music cannot. What mechanism exists that could possibly explain a plant having any kind of response to music? 

Plants respond to heavy wind by growing smaller or by hugging the ground (think alpine vegetation). High winds could generally be seen as a taxing force in the plant world so why would music make plants grow taller and more vigorous? In my opinion, this idea is not a satisfying explanation. As stated above, music doesn't come close to the raw physical power of wind so there could be something else at work. 

In a study done by Margaret E. Collins and John E.K. Foreman out of the University of Western Ontario in London, Canada, they demonstrated that plants responded to different kinds of tones. The tones were either pure (without variation) or random. The results did not show any sort of negative responses from the plants, but rather the plants showed different rates of growth. Plants exposed to pure tones grew better than those exposed to random tones. 

The mechanism they hypothesized for the increased growth in pure tone plants was that the pure tones were able to move air, however slightly, around the leaf. Plants don't like stagnant air and thus, slight air movement is likely to be more beneficial. The random tones did not produce as vigorous of a response, but the plants still grew. It is possible that the random tones caused less air movement around the plants and, because of this, they did not grow as quickly.

Another explanation that seems plausible was put forth by USCB via their science line. They feel that one possible explanation is that the plants aren't the ones responding to the music, but rather the gardener. If you are listening to music while caring for your plants, then chances are it is music you enjoy. If you are like me, then music really has the power to put you in a good mood. If you are in a good mood then chances are you are more likely to take better care of your plants.

All in all, this is an interesting idea. As I said above, the results are mostly controversial and new agey. There are some tantalizing papers that have been published but their methods have been heavily scrutinized. It seems like this is one of the more popular science fair projects for kids to explore and really, anything that gets kids thinking about science and plants is a cool idea in my book. Until more hard science is done on the subject, we can't say for certain. Either way, I will continue to rock out to my favorite tunes and maybe, just maybe, my plants are benefiting from it too.

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

Shade Gives This Begonia the Iridescent Blues

Believe it or not, the blue iridescence of Begonia pavonina is an evolutionary adaptation to extracting the most amount of energy out of the dim light that makes it through the thick rainforest canopy above. Even more bizarre, it works thanks to an interesting property of quantum mechanics. 

Native to Malaysia, B. pavonina lives out its life in deep shade. Most of the sunlight that hits this region is absorbed by the thick canopy of trees above. As such, eking out an existence is a challenge for these understory herbs. That is where this fantastic blue iridescence comes in. To understand it better, researchers had to take a closer look at its cause. 

Inside any photosynthetic leaves resides the chloroplasts. Chloroplasts are filled with tiny stacks of membranous compartments called "thylakoids." This is where the light reactions of photosynthesis take place. Now, in most plants, these thylakoids are haphazardly distributed throughout the chloroplast. This is not the case for B. pavonina. For this species, the thylakoids are arranged in a very precise way.

It is this precision that gives the leaves their iridescent color. Their placement causes blue wavelengths of light to be reflected. This isn't a big loss for the plant as most of the blue light is absorbed by the canopy above anyway. What it does instead is quite fascinating. The stacked thylakoids act like a dense crystal. When light enters the chloroplasts of B. pavonina it is physically slowed down.

This effect is known to quantum physicists as "slow light." Whereas light traveling through a vacuum maintains a constant speed, light passing through different types of matter can actually be slowed down. By slowing light as it passes through the chloroplasts, the thylakoids are able to take advantage of what little light the leaves are able to intercept. For B. pavonina, this equates to a 10% increase in photosynthetic rates. Coupled with an increase in the absorbance of red-green light, one can understand why this is such an advantage. 

Another interesting aspect of its physiology is the fact that B. pavonina produces both "normal" and iridescent chloroplasts. It is thought that this is a form of backup for the plant. In instances where enough light actually does make it through to the forest floor, B. pavonina can use its normal chloroplasts instead. It should be noted that this is not the only case of blue iridescent leaves in the plant kingdom. Many other species including spike mosses, ferns, and even orchids exhibit this trait. Even leaves that don't appear iridescent to our eyes may be utilizing nanostructures such as those seen in B. pavonina to increase their photosynthetic efficiency in low light conditions. It is very likely that many different kinds of plants are physically manipulating light to their benefit.

Photo Credit: Michael Perry

Further Reading:

[1]

Meet the Toad Lilies

Fall is such a great time to take advantage of some awesome deals at your local nursery. Plants that have gone out of bloom or are in the process of going dormant always seem to have a lower price tag on them. What's more, fall is the best time, at least in the temperate zones, to plant most things. However, a fall stroll around a nursery or garden center isn't without floral beauty. One group of plants that are exceptionally beautiful at this time of the year are the toad lilies.

Native to parts of China, Japan, the Himalayas, Formosa, and the Philippines, the genus Tricyrtis is growing in popularity as a horticultural curiosity. It's not hard to believe once the true beauty of this genus is realized. In the wild, these plants are denizens of shady forest hillsides and are often encountered on wet slopes. Being a member of the lily family, the floral parts of these plants are arranged in multiples of three. Genetic analysis puts this genus into the same group as Calochortus lilies and indeed, they do share some superficial similarities.

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

The flowers are the real selling points of this genus. They kind of look like a cross between a lily and a passion flower. The name toad lily comes from the speckled appearance of the leaves and petals. That is by and large the only toad-like qualities these plants have other than preferring moisture of course. There has been a lot of debate over what may pollinate the flowers. It is believed that at least some species such as Tricyrtis nana reproduce mainly via self-fertilization whereas others seem to attract mainly bumblebees.

Further Reading: [1] [2]

The Devil's Walking Stick

The name "Devil's walking stick" just sounds cool. You can imagine my excitement then when I first laid eyes on the species it refers to. Aralia spinosa is no ordinary tree. It is a hardy species ready to take advantage of disturbance. Armed with spikes and a canopy that looks like it belongs in some far off tropical jungle, the Devil's walking stick is a tree species worth knowing. 

I used to think that spikenard (Aralia racemosa) was the most robust member of the aralia family found in North America. Not so. The Devil's walking stick is a medium sized tree capable of reaching heights of over 30 feet (10 m). Most interesting of all, its triply compound leaves are the largest leaves of any temperate tree in the continental United States.

The Devil's walking stick can be found growing in disturbed areas and along forest edges throughout a large swath of eastern North America. When young it is a rather spiny lot. These are not true spines, which are modified parts of leaves, but rather prickles, which arise from extensions of the cortex or epidermis. 

As it grows, however, it loses a lot of its prickliness. Such armaments are costly to produce after all. It is believed that younger plants develop these structures while they are still at convenient nibbling height, only to lose them once they grow big enough to avoid hungry herbivores. Research has shown that most herbivorous mammals alive today do not bother much with the Devil's walking stick, which has led some to suggest that these defenses evolved back when this side of the continent was brimming with much larger herbivores such as elk and bison. 

As if the giant compound leaves of this tree were not stunning enough, the surprisingly large inflorescence is sure to blow you away. Typical of the family, it consists of hundreds of tiny green flowers. Despite their size, they are a boon for pollinators. A tree in full bloom comes alive with bees and butterflies alike. Flowers soon give way to clusters of berries, which are a favorite food among birds. All in all this is one cool tree.

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

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]