An Endemic Houstonia

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

The weathered peaks of the Southern Appalachians are home to a bewildering variety of plant life. This region is thought to have provided refuge for many different types of flora and fauna pushed south by repeated glaciation. High humidity and precipitation coupled with a variety of microclimates has allowed plants to flourish and evolve over the millennia. In fact, a handful of species are found nowhere else in the world. One of these montane endemics is none other than a species of Houstonia. 

Some feel it best designated as a subspecies, Houstonia purpurea var. montana, whereas others feel that both morphological and reproductive distinctions deserve it a status as its own species, Houstonia montana. I prefer to refer to it as the Roan Mountain bluet. Either way, this unique little plant can be found  growing among rocky summits and balds on only a handful of mountain tops between Tennessee and North Carolina.  

This species requires disturbance to survive. Without the constantly shifting landscape characteristic of high altitude regions, this little plant would quickly be overtopped and outcompeted by more aggressive vegetation. This is not a lifestyle unique to this little bluet. Many of the worlds rare plant species require some level of disturbance to release them from competition with other more common plant species. Aside from competition, one of the largest threats to the continued survival is trampling by hikers. It is always important to watch where we hike. A little bit of attention can go a long way for our botanical neighbors. 

Photo Credit: BlueRidgeKitties (http://bit.ly/1dJ7SkA)

Further Reading:

http://www.esajournals.org/doi/abs/10.1890/1051-0761(1998)008%5B0909:PORPOA%5D2.0.CO%3B2

http://www.bioone.org/doi/abs/10.3159/1095-5674(2007)134%5B177:GOTRSA%5D2.0.CO%3B2

http://link.springer.com/article/10.1007/s10682-011-9539-x#page-1

http://www.jstor.org/discover/10.2307/4032597?uid=2&uid=4&sid=21106703459663

Rusty Mustards

Believe it or not, what you are seeing here is the same species of plant. The one on the left is the normal reproductive state of a Boechera (Arabis) mustard while the one on the right is the same species of mustard that has been infected by a rust fungus known as Puccinia monoica.

The interaction of these two species is interesting on so many levels. I spent an entire summer, along with my botanical colleagues, completely stumped as to what this strange orange-colored plant could be only to eventually find out that it was a mustard that has been hijacked! The fungus in question, P. monoica, is part of a large complex of interrelated rust fungi who are quite fond of mustards. The reason for this all boils down to reproduction.

The lifecycle of P. monoica begins when spores land on a young mustard plant and invade the host tissue. As they grow, they gain more and more nutrients from the mustard. Eventually the fungi effectively sterilizes the mustard and causes it to begin forming what are referred to as "pseudoflowers." The pseudoflowers are basically leaves that have been mutated by the fungus to look and smell a lot like other plants blooming in early summer.

The pseudoflowers produce a sticky, nectar-like substance that is very attractive to pollinators. The mimicry even goes as far as to produce yellowish pigments that reflect UV light, making them an even more irrisistable target for passing insects. On each pseudoflower are hundreds of small cups known as spermatogonia. These house the sex cells of the fungus. Visiting insects get covered in these sex cells, which they will then transfers to other infected plants thus achieving sexual reproduction for the fungus.

Still with me?

At this point, the pseudoflowers stop producing color and nectar and instead, the fused sex cells germinate into hyphae that begin to form specialized structures called "aecia." The aceia house the spores that will be responsible for infecting their secondary host plants, which are grasses. Spores blow about on the wind and, with a little luck, a few will land on a blade of grass. The spores germinate and infect the grass. From there, structures called "uredia" are formed that go on to produce even more spores to infect even more grass. Eventually, structures called "telia" are formed on the grass and the cycle finally comes full circle. The telia produce the spores that will go on to infect the original mustard host plants.

Whew! To have stumbled across an evolutionary drama such as this serves as a reminder of just how much in nature goes largely unnoticed every day.  

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

The Truth About Peat

Peat moss is not a sustainable option for gardening on any level.

No matter how good of a product it may be for anyone, the mining of peat moss is an incredibly destructive industry that is harming not only sensitive habitat but some of our largest carbon stores on the planet. Now, before you think I'm all up on my high horse about this subject, please note that I still use it in some of my gardening projects. It is hard not to. I am writing this post as a cry for help in order to get a conversation going about some sustainable and effective alternatives to this "blood soil."

Peat is the product of the natural processes that bogs go through. Sphagnum moss, the main species of a bog ecosystem, and other plant materials don't decompose in bogs. Instead they build up and compact to form what we know as peat moss. For centuries, this has been harvested and dried as a source of heat and energy for native peoples. Today, because of its moisture holding abilities and rather sterile, acidic nature, it is heavily mined for the horticultural trade. Most of the peat sold comes from Canada. Canadian companies mine their bog habitats for this product. The Canadian peat companies will tell you that it is a renewable resource and that mitigation offsets any damage being done. This is a bold faced lie. Bogs are incredibly sensitive habitats. They are the product of thousands of years of very particular natural processes. They hardly regenerate themselves if at all. Mitigation efforts are also pointless. Bogs that have been "mitigated" do not return to their fully functioning state ecologically.

To make matters worse, the industry loves to claim that there are no alternatives to peat moss out there. This is simply not true. I have researched some interesting sustainable alternatives to peat moss. One product is coconut coir "dust." This product comes from ground up coconut husks. From what I have read, it is also a much more sustainable option. Now, a few things must be said about the efficacy of this material. First off it is naturally high in salt. Most brands must be thoroughly washed before using. I have gotten around this issue by purchasing coconut coir used for amphibian and reptile bedding. It comes in compact bricks and it has the lowest salt levels on the market. Also, it is really low in nutrient value. I do some water gardening so I have a very mature fish tank running and using aquarium water seems to solve this issue for me. Adding coffee grounds can mitigate this as well. I have heard mixed reviews about coir and it is not necessarily the best choice for all types of seeds but it works quite well for me and in the last 4 growing seasons I have finally switched to using coir for germination.

By far my favorite media to use is good compost. Having ready access to a big pile goes a long way. Because compost can be very rich and heavy, I like to mix in wood chips and gravel. This not only weighs my pots down and keeps them from falling over, it increases the amount of roots my plants produce considerably. Every time a root comes into contact with a piece of gravel or wood chip, it branches off hundreds of tiny root hairs, thus increasing the surface area available for water and nutrient absorption. Since I switched over to mixing my own soil using compost, I have noticed my plants are more vigorous and are flowering more often. 

Another option I have come across is pine bark. I have not used this but some research papers rank it as good as peat moss in seed germination trials. Has anyone here tried this? If anyone has an opinion on this subject or better yet, first hand experience, PLEASE chime in. If we can't make growing plants a sustainable process then what good are we as a species? Finally, does it make sense to destroy one habitat to foster a handful of species in your back yard?

Further Reading: 

http://www.sciencedaily.com/releases/2009/09/090904165253.htm

http://hortsci.ashspublications.org/content/44/2/312.full.pdf+html

http://www.usu.edu/cpl/PDF/CoconutCoirPaper.pdf

http://www.puyallup.wsu.edu/~linda%20chalker-scott/horticultural%20myths_files/Myths/Horticultural%20%20peat.pdf

http://flrec.ifas.ufl.edu/Hort/Environmental/Media_Nutrition/COIR%20potential.htm

Colorful Claytonia

If you live where spring beauty, specifically Claytonia virginica, is native, then you may have noticed great variations in flower color. We all know the influence pollinators can have on flower shape and color but how do we explain populations with such a spectrum?

Like me you might be thinking that it is related to its growing conditions. Well, researched based out of Indiana University would suggest otherwise. It turns out, the variety of flower color in Claytonia has to do with opposing natural selection from herbivores and pathogens.

In a 2 year study, researchers made some amazing discoveries about how herbivores, pollinators, and pathogens can interact to produce the variety of flower colors one can find in any given Claytonia population. First, they made sure that Claytonia flower color is not a result of soil pH or anything like that by growing a ton of them in different conditions. They were able to demonstrate that flower color is indeed genetic and is controlled by a couple different compounds. Crimson coloring comes from a compound called "cyanidin" and white colors comes from two flavonols, "guercetin" and "kaempferol". Researchers then used spectrometry to analyze flower colors throughout the population and found 4 distinct color morphs ranging from all white to mostly crimson.

As it turns out, the flavonol compounds have pleiotropic effects in Claytonia. While they do produce white pigments, they also help defend the plants against herbivory and pathogens. Researchers then used a multitude of different analytical methods to assess overall fitness of each color morph and the results are jaw-droppingly cool to say the least.

Fitness of Claytonia was measured as total fruit production and total seed set. Because Claytonia needs a pollinator to visit the plant in order to produce fruit and set seed, reproduction is directly linked to pollinator preference. This research showed that pollinators, which for Claytonia are solitary bees, do, in fact, prefer crimson color morphs. This helps to explain the greater number of crimson colored flowers in in many populations because the more pollinators that visit a flower, the higher overall fitness for that plant. What it does not explain though, is why white morphs exist in the population at all.

As stated above, the flavonols that produce white pigmentation also beef up the plants defenses. It was found that white colored flowers experienced significantly less predation than crimson flowers. This is big news because herbivory has serious consequences for Claytonia. Plants that receive high levels of herbivore damage are far more likely to die. Because of this, white morphs, even with significantly less reproductive fitness, are able to maintain themselves in any given population.

If you're at all like me then you may need to pick you jaw up off the ground at this point. But wait! It gets cooler.... In areas where other white flowering plants like Stellaria pubera abound, white Claytonia morphs are even more rare. Why is this exactly? Well, this is due to a push towards a more pollinator-mediated selective pressure. In areas where many plants share the same flower color, it pays to be different. This causes a selective pressure in these Claytonia populations to favor even more crimson color morphs.

Isn't evolution amazing?

Further Reading:

http://bit.ly/1QxVy5Q

http://plants.usda.gov/java/profile?symbol=clvi3

Echoes of a Glacial Past

Climate change is often talked about in the context of direct effects on species. However, as John Muir so eloquently put it, "When we try to pick out anything by itself, we find it hitched to everything else in the Universe." In essence, nothing is ever black and white and the research I am writing about today illustrates this fact quite well.

Ants and plants have some very intricate interactions. A multitude of plant species rely on ants as their seed dispersers. Many of these plant species are spring ephemerals that take advantage of the fact that there is little else for ants to eat in the early spring by attaching fatty capsules to their seeds that are very attractive to foraging ant species. We refer to seed dispersal by ants as “myrmecochory.”

There are two big players in the foraging ant communities of eastern North America, the warm adapted Aphaenogaster rudis and the cold adapted Aphaenogaster picea. The cold adapted A. picea emerges from winter dormancy early in the spring while the warm adapted species emerges from dormancy much later in the spring. In the southern portions of their range, A. rudis outcompetes A. picea.

What is the big deal? Well, the researchers looked at two plant species that rely on these ants for seed dispersal, Hepatica nobilis and Hexastylis arifolia. Hepatica nobilis sets seed early in the spring, relying on ant species like A. picea to disperse its seed whereas Hexastylis arifolia sets seed late in spring, which is prime time for A. rudis. Researchers noticed that, in the southern portions of their range where A. picea had been displaced, Hepatica has a very clumped and patchy growth habit where farther north it did not. Hexastylis on the other hand seemed to have a more normal growth pattern in the south.

By performing some transplanting experiments and examining foraging and seed dispersal, they found that the absence of A. picea in the south spelled ecological disaster for Hepatica. It continues to set seed but because A. rudis emerges long after seed set, it is not filling the gap left by the missing A. picea. Hexastylis, which only grows in the south and sets seed much later, does just fine with the warm adapted A. rudis. Farther north where A. picea still rules, Hepatica has no trouble with seed dispersal but Hexastylis drops out of the ecosystem entirely. In essence, because of warming climate trends since the end of the Pleistocene, Hepatica is falling out of sync with its mutualistic ant partner in the southern portions of its range and, in time, may become extirpated.

Further Reading: [1]

When One Becomes Two

One of the most stunning spring flowering plants in the eastern forests has to be blue cohosh (Caulophyllum spp.). Around this time of year they begin poking up through the leaf litter, their deep purple stems gradually giving way to shades of blue and green as the leaves and flowers expand into the springtime sun. They seem almost otherworldly and finding them among the speckled leaves of trout lily is a sight I will never tire of.

For as long as it has been known, North America's Caulophyllum has been considered a single species, Caulophyllum thalictroides. The specific epithet hints at how similar this species can look to the meadow rues (Thalictrum spp.). However, a keen observer could tell you that there are apparent differences between some blue cohosh populations, especially in the northeast. Some cohosh flower much earlier than others. Also, there are differences in flower color as well. Some plants sport flowers decked in deep maroon whereas others are pale green. These differences have led some authors to list the purple flowering variety as a subspecies, Caulophyllum thalictroides giganteum.

Caulophyllum thalictroides

Photo by Tom Potterfield licensed under CC BY-NC-SA 2.0

More recently, however, it has become apparent that these two varieties may actually be separate species. Though their ranges overlap, what is now being called Caulophyllum giganteum is distributed much farther north than C. thalictroides. The key differences between these two has to do with flowering time. If these two species become reproductively active at different times, then they are in fact reproductively isolated from one another. Though they can hybridize, the resulting seeds experience reduced viability and do not perform as well as either parent.

Photo Credit: Tom Potterfield (http://bit.ly/1E0JcQ5)

Further Reading: [1] [2]
 

The Tallest of Palms

High up in a mountain valley in Colombia grows one of the most remarkable palms in the world. Known scientifically as Ceroxylon quindiuense, the Quindío wax palm towers like a lanky monolith above the surrounding vegetation. Not only is this the tallest species of palm in the world, it is, by extension, the tallest monocot as well.

Standing at heights of over 160 feet, the Quindío wax palm looks all the stranger with its narrow trunk and tuft of fronds all the way at the top. It is called a wax palm because members of this genus produce a waxy substance from their trunk. In the past, this wax was harvested for its use in making torches. Until electricity became widely available, these palms were felled en masse for this purpose.

Quindío wax palms are slow to mature. For at least 15 years they focus much of their energy on radial or outward growth of the trunk. For 15 years, all the tree puts out are three pinnate leaves. Things change once the tree hits 15. It will begin its climb into the sky. Every year it sheds leaves, which creates a dark ring around the trunk. Because of this, it is easy to estimate the approximate age of any given wax palm. Count the rings and add 15 years for stem development plus another 5 for a full crown. It is believed that these palms can take upwards of 80 years to reach sexual maturity!

Because of its limited geographic range, Quindío wax palms are at risk of extinction. The young fronds are favorites among Catholics of the region for their use in Palm Sunday ceremonies. Stands that exhibit heavy harvesting have a hard time of recovering. At the same time, their native range is quickly being converted to pasture land as well as other forms of agriculture. Even if trees are left standing, their seeds find it difficult to germinate and survive under the altered microclimates of these human environments.

Luckily for Ceroxylon quindiuense, the government of Colombia recognizes how special this species is. Not only is it now the national tree and emblem of Colombia, its is now a protected species. All logging of Quindío wax palms is illegal. Still, major portions of their remaining populations are located within pasture lands.

Photo Credit: nuria mpascual (http://bit.ly/1CImC7T)

Further Reading:
http://bit.ly/1CImCEP

http://www.iucnredlist.org/details/38467/0

The Time Has Arrived!

It is officially spring ephemeral season here in western New York! 

Hepatica acutiloba 

Claytonia caroliniana 

Snowdrops

Photo by Gideon Chilton licensed under CC BY-NC 2.0

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

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

View fullsize

Map by Nalagtus licensed under CC BY-SA 4.0

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

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

Photo Credit: [1] [2]

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

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

Deaf Plants

Photo by Barney Livingston licensed under CC BY-SA 2.0

As we continue to make advances in the field of genetics, the cost of genome sequencing is getting cheaper and cheaper. We are sequencing entire genomes seemingly overnight. As we learn more about this code that programs every living thing on this planet, the more surprises we uncover. One such surprise came when researchers sequenced the genome of a little mustard known as Arabidopsis thaliana. As it turns out, this lowly little plant has more in common with our own genetic lineage than we ever thought possible. 

One interesting thing that turned up in the genome of Arabidopsis were a handful of genes associated with hearing in humans. For all intents and purposes, plants can't hear. They don't have ears nor do they have a nervous system capable of translating vibrations into what we know as sound. Why, then, were these genes present in a plant? 

Humans contain over 50 genes associated with hearing. A mutation in any of these can cause hearing loss. Arabidopsis shares at least 10 of these genes with us. In humans, one of these shared genes codes for proteins that are involved in forming the microscopic hairs within our inner ear that pick up sound waves. Again, why would a plant need this? When researchers mutated this gene within Arabidopsis, a surprising thing happened. 

Plants produce hair-like structures from their roots. These root hairs vastly increase the amount of surface area the root has for soaking up water and nutrients in the soil. A mutation in one of these hearing genes causes the root hairs to fail to elongate. As a result, the plant then has trouble absorbing things. 

Hearing genes are by no means the only genes we share with plants either. Within the genome of Arabidopsis, researchers have discovered over 100 genes involved in human diseases including breast cancer and cystic fibrosis. Though the differences between humans and plants seem insurmountable, we nonetheless share a common ancestor. The genes that control the development of an organism were laid down long before our lineages became distinct. It would appear that many genes don't change but are simply adopted for different purposes. It is discoveries like these that stand as a stark reminder that so-called "science for the sake of science" is incredibly important. 

Photo Credit: virken (http://bit.ly/1DI50Qz)

Further Reading:

http://www.plantphysiol.org/content/146/3/1109.short

http://nar.oxfordjournals.org/content/31/4/1148.short

The Vernal Dam Hypothesis

I have already established that spring ephemerals are badasses (http://bit.ly/1CsEtj1) but what I am about to tell you is really going to kick it up a notch...

While offering our native pollinators some much needed food resources along with giving us humans a much needed jolt of life after a long and dreary winter, spring ephemerals like these trout lilies (Erythronium americanum), are important nutrient sinks for forests.

Back in 1978, a guy by the name of Robert Muller put forth a very intriguing idea known as the vernal-dam hypothesis. Basically, he proposed the idea that soil nutrients are heavily leached into waterways during the spring melt and subsequent rains. Where spring ephemerals are present, they act as nutrient sinks, taking up much of the nutrients that would otherwise be lost. The idea was well liked but unfortunately, the important assumptions of this hypothesis were not tested until the last decade or so. Recently, more attention is being paid to this concept and some research is being published that do indeed support his claims!

Though the research does not address whether or not the nutrients really would be lost from the system in the absence of spring ephemerals, it is showing that some species really do serve as nutrient sinks. Trout lily, for instance, is a massive sink for nitrogen and potassium. As they grow they take in more and more. When the warmer summer weather hits and the leaves die back, they then release a lot of nutrients back into soil where vigorously growing plants are ready to take it up. It should be noted that trees will still take in nutrients even before leafing out for the summer. One study even showed that net uptake of nitrogen and potassium by a variety of spring ephemeral species is nearly equal to the net annual losses. I must admit that I did not quite understand what the "losses" are in this particular study but the evidence is tantalizing nonetheless. In one example, nitrogen uptake by ephemerals was 12% of the nitrogen in annual tree litter!

Whether or not it is shown that nutrients taken up by ephemerals would otherwise be loss is, in my opinion, beyond the point. What has been demonstrated in the ability of spring ephemeral species to uptake and store vital forest nutrients suggests major ecosystem benefit! Furthermore, when you consider the fact that mycorrhizal fungi are non-specific in most cases and will bond with many different plant species and then go as far as sharing nutrients among the forest flora, you really start to see a big picture story that has been playing out all over the world for millennia. 

Further Reading:

http://www.jstor.org/discover/10.2307/2937357?uid=3739256&sid=21102213017237

http://iub.edu/~preserve/docs/library/BlankJL_1980.pdf

http://www.jstor.org/discover/10.2307/2425383?uid=3739256&sid=21102213017237

http://link.springer.com/article/10.1007/s00442-002-0958-9#page-1

The Badass Spring Ephemerals

Spring ephemerals and the word "badass" are probably not frequent associates but I am here to argue that they should be.

Spring ephemeral season is here for some and just around the corner for the rest of us. It's my favorite wildflower season and I often go missing in the woods for those first few weeks of spring. It is easy to look at their diminutive size and their ephemeral nature as signs of delicacy but these plants are anything but. In fact, when one examines the intricacies of their lifestyle, they can see that spring ephemerals make most other plants look like total softies.

Spring ephemerals, the designation of which gets blurred depending on who you ask, have to complete most of their life cycle in the early spring before the trees and understory shrubs leaf out and completely take over most of the available light. This is an incredibly tough time to be a plant. Soil temperatures are low, which makes nutrient and water uptake a difficult task, all but the most robust pollinators are still sound asleep, and there is the ever present danger of a hard frost or freak snow storm. These factors have led to some incredible adaptations in all of the species that emerge around this time. Whereas each species has its own methods, there are some generalities that are common throughout.

For the most part, spring ephemerals have two distinct growth phases; epigeous (above ground) and hypogeous (below ground). The hypogeous phase of growth takes place throughout fall and winter. Yes, winter. This is the phase in which the plants put out more roots and develop next season’s buds. This goes on at the expense of nutrients that were stored the previous spring. Once spring arrives and soils begin to warm, the plants enter the epigeous phase of growth where leaves and flowers are produced and reproduction occurs. This is an incredibly short period of time and spring ephemerals are well suited for the task.

Typical growth cycle of many spring ephemerals [Source}

For starters, photosynthetic activity for these species is at its best around 20 °C. Photosynthetic proteins activate very early on so that by the time the leaf is fully expanded, the plant is a powerhouse of carbohydrate production. Photosynthesizing in cool temperatures comes at a cost. Water stress in at this time of year is high. Low soil temperatures make uptake of water difficult and it is strange to note that many species of spring ephemeral have very little root surface area in the form of root hairs. These species, however, have extensive mycorrhizal associations which help assuage this issue.

Nutrient availability is also very limited by low soil temperatures. Chemical reactions that would unlock such nutrients are not efficient at low temperatures. Again, spring ephemerals get around this via their increased mycorrhizal associations. It should be noted that some species such as those belonging to the genus Dicentra, do not have these associations. In this situation, these species do in fact develop extensive root hairs as a coping mechanism. Despite specific adaptations for nutrient uptake, you will rarely find spring ephemerals not growing in deep, nutrient-rich soils.

Again, we must keep in mind that all of this is happening so that the plant can quickly complete what it needs to do in the few weeks before the canopy closes and things heat up. It has been observed that high temperatures are associated with slowed growth in most of these species. As temperatures increase, the plants begin to die back. Another adaptation to this ephemeral lifestyle is an increased ability to recycle nutrients in the leaves. As spring temperatures rise, the plants begin to pull in nutrients and store them in their perennial organs. They also show specific compartmentalization of energy stores. In many species, seed production is fueled solely by energy reserves in the stem. Some underground storage structures then receive nutrients to fuel autumn and winter growth while others receive nutrients to fuel leaf and stem growth in the early spring.

Despite all of these amazing adaptations, life is still no cake walk and growth is painstakingly slow. Many species, like trout lilies (Erythronium spp.), can take upwards of 8 years to flower! 8 years!! Think about that next time you are thinking of harvesting or picking some. Even worse in some areas are white tailed deer. East of the Mississippi their populations have grown to a point in which their foraging threatens the long term survival of many different plant species. Especially hard hit are spring ephemerals as they are the first plants to emerge after a long winter of near starvation. 

I hope this post wakes people up to how truly badass these species really are. As our climate warms, we can only speculate how things are going to change for many of them. Some research suggests that things may get easier whereas others suggest that conditions are going to get harsher. It's anyone's guess at this point. As populations are wiped out due to development or invasive species, we are losing much needed genetic diversity and corridors for gene transfer. This is yet another reason why land conservation efforts are so vital to resilient ecosystems. Support your local land conservancy today!

Spring is here and things are getting underway. Get out there and enjoy the heck out of the spring ephemerals! In a few short weeks they will be back underground, awaiting the next cold, damp spring.

Further Reading: [1] [2]

Assorted Cryptograms

A Strange Gymnosperm From Africa

Photo by Petr Kosina licensed under CC BY-NC 2.0

What you are looking at here is not just a pile of discarded leaves. It is indeed a living plant. Would you believe me if I told you that it is a distant relative of pines, spruces, larches and firs? It's true! This right here is Welwitschia mirabilis, a representative of an ancient lineage of gymnosperm!

Photo by Petr Kosina licensed under CC BY-NC 2.0

Welwitschia is endemic to the Namib Desert of Africa. It is hard to picture any plant living in such a dry area. In some years it never even rains. Welwitschia persists despite this fact. It tends to grow in watercourses and outcrops, thus enabling it to gather what precious little rain does fall. It has a deep taproot suggesting that it relies heavily on ground water. The leaves of Welwitschia also have high amounts of stomata on both surfaces enabling it to absorb water directly from the fog that regularly blows through when colder air currents mix with hot air from the desert.

For a long time it was believed that Welwitschia represented true neoteny, which is the retention of juvenile characteristics into adulthood. It was thought that Welwitschia was nothing more than a sexually mature seedling with exaggerated cotyledons. This idea was later abandoned when Martens showed that Welwitschia do develop further than the seedling stage. What really happens is the apical bud, which is responsible for vertical growth in plants, dies quite early on in development. In essence, Welwitschia has lost its "head."

I was not kidding when I said that Welwitschia is a gymnosperm. Once sexual maturity is reached, cones are produced. Individual plants are either male or female and unlike many of its relatives, Welwitschia is not wind pollenated. Instead it relies on insects to transfer pollen from male cones to female cones.

Probably the most remarkable aspect of Welwitschia ecology is its longevity. Individual plants can live well over 1000 years. Some individuals are estimated at around 2000 years old! In such a harsh desert environment, persistence is the key to survival for Welwitschia.

Photo Credit: Petr Kosina

Further Reading:
http://www.jstor.org/discover/10.2307/2442386…

http://www.plantzafrica.com/plantwxyz/welwitschia.htm

Something Smells...

Plant nurseries are a dangerous place for me. Well, not really me so much as my wallet. I am always on the lookout for new and interesting plant friends to bring home. I recently visited a local nursery that has 4 hoop houses worth of plants to ogle. As I was walking the crowded alleyways between row after row of botanical treasures, something tucked away in a back corner caught my eye. There was a stark juxtaposition between burgundy and deep green that I simply could not ignore. I tip toed around a variety of succulents, dracaena, and gesneriads to investigate this colorful curiosity. 

As I approached this odd little plant I realized there was a long spike jutting out of the top. Ah, so this was some sort of peperomia. At this point I could see why it was kept among succulents. The leaves of this peperomia are quite succulent. Like fat little canoes, the leaves appeared to have green window-like surfaces that quickly gave way to a red bilge. This was truly unique. I had to have it. 

Despite the fact that it was the only one of its kind, I got it for a steal. It wasn't planted very well so I had to be quite careful getting it home. Mixing up soil can be fun, especially when you know the plant you are catering to. This was not one of those cases. Regardless, the succulent nature of the plant hinted at a need for a well drained mix. Three parts gravel to one part compost should do the trick. Despite its size, the plant had an under-developed root system. This explains why it was so floppy on the ride home. Once it was in its new pot, I had to go about picking out a perfect spot on the shelf. I knew that plants like Crassulas and aloes turn colors under high light so I figured this would be my best bet at preserving the beauty of this specimen. I watered it and sat back to enjoy its beauty among all the other plants in the collection. 

Later that day I began noticing an odd smell. It wasn't necessarily offensive yet it wasn't easily ignored either. It was also restricted to one area near the plant shelf. My nose didn't reveal the source. I put shoes outside and checked the area for anything that may be starting to rot. Nothing. After a while I must have gotten used to it and after a couple hours I forgot about it. Days went by and every once in a while the smell would creep its way into my nose. I was very confused and yet too busy to be serious about locating the source. 

I like to show off my plants so I made sure to draw attention to this new peperomia any time someone dropped by for a visit. It seemed to resonate well with friends. After a series of inquiries into this plants identity I decided to do my homework. Simply referring to it as a mystery peperomia wasn't satisfying enough. Luckily the internet exists. A quick image search for "succulent red peperomia" gave me my answer. 

My beautiful plant friend was none other than Peperomia graveolens, an endemic of mountainous forests in Ecuador. To my surprise, this is not a species that enjoys a lot of sun. The burgundy undersides are thought to assist the plant in soaking up as much sunlight as possible as it ekes out a living under the canopy. I guess I was going to have to move this plant to a lower shelf. The good news is that the soil mixture I made was going to work. There was no need to disturb the meager root system any more than I already had. 

Apparently this species is only known from two wild populations. All of the plants in cultivation are descendants of collections made in 1973 by some German botanists. This is truly a special plant! As I was reading various plant care websites, a recurring theme in the writing caught my attention. The inflorescence of this species is said to have a "mousey odor." I have seen that term before but, even after years of working in pet stores, I couldn't quite picture what a mousey odor would be like. Urine perhaps? Then I realized something. That strange odor was still present in and around the plant shelf. Could this be what I was smelling? I carefully picked up the plant and gave it a sniff. Yep! There is was. I still don't think of mice when I smell it but I can see how such descriptive terms could be applied. Regardless, my introduction to this wonderful little plant has made it all the more interesting. This is one of the main reasons I keep house plants. My collection is my own little botanical garden that I fill with species that capture my imagination. 

Further Reading:

http://www.iucnredlist.org/details/45780/0

Plant "Sight"

As the sun rises higher into the sky and our days get incrementally longer, I am thinking about plant sight. I'm not talking sight as you or I know it but rather their own unique brand of knowing where the light is and how to respond to it. Anyone that has ever grown plants will have undoubtedly recognized the way in which houseplants lean towards the nearest window or sunflowers track the sun's path through the sky each day with their blooms. Plants need the light and know how to respond to it but how do they do this without eyes, nerves, or a brain to process the world around them?

One of the first tantalizing pieces of evidence to this puzzle came from none other than Darwin himself. With the help of his son he carried out a series of experiments on seedlings using a candle lit room and rather ingenious methodology. They knew that seedlings naturally bent towards candle light so they were curious as to which part of the plant was responsible for this response. They cut off some of the seedling tips, covered the tips of some with light-proof caps, and covered others with transparent glass caps. There were also control seedlings as well as seedlings in which they only covered the stems, leaving the tips exposed. What they found was that only the seedlings with their tips cut off as well as those with light-proof caps didn't bend. 

So, it appeared that the tip of the plant was where "sight" occurs, at least when plants are trying to figure out where the light source is emanating, however, this is not the full picture. Plants can also measure the length of day. Known as photoperiodism, many species of plants will regulate growth and flowering based on day length. Long-day plants will only flower when days are at their longest. The opposite is true for short-day plants. But the question remains, how do they know? Scientists quickly figured out that they could mess with this photoperiodism in the greenhouse by turning lights on in the middle of the night, a technique that is a boon to the horticulture industry. 

Research into this revealed that different wavelengths of light have different effects. Blue or green light, for instance, does not do anything to upset a plants flowering schedule whereas red light does. Even stranger, the relative shade of the red light also has an effect. Shining a bright red light on a long-day plant in the middle of the night will cause it to flower while you can cancel this effect by shining dark red light right after. This may seem weird but it makes sense when you consider how these plants evolved.

It is not actually the length of day that plants measure, but rather the length of night. Shorter nights mean longer days, an excellent cue that the environment is favorable for flowering. By turning on lights in the middle of the night, you are effectively simulating short nights. In nature, plants receive bright red light when the sun is rising in the sky and dark red light as it sets. Bright red light activates chemical cues for flowering and dark red light turns them off. Only when the bright red signal is turned on longer than the dark red signal will the plants actually flower. 

The chemical responsible for this "color vision" in plants is known as "phytochrome." Unlike Darwin's experiments, shining light on the tip of the plant has no effect on phytochrome. However, shining light on even a single leaf will elicit a response. Plants in which the leaves have been pruned will not react to red light at all. Though I can't speak for leafless plants like cacti, I am sure the concept remains the same, albeit more adapted to their lifestyle. 

In total, roughly 11 photoreceptive compounds have been identified in plants. Though they do not perceive images as you and I do, their sense of "sight" is nonetheless quite sophisticated. Plants feed on light so it is no wonder that they have quite the chemical arsenal for responding to it. 

Further Reading:

http://www.plantphysiol.org/content/125/1/85.full

Bacterial Enduced Shield

Photo by Dick Culbert licensed under CC BY 2.0

Legumes are famous the world over for their nitrogen fixing capabilities. These hardy plants can live in soils that would otherwise not support much of anything. As such, nitrogen fixation is one reason that the legumes have found themselves as a focus of agriculture. However, this ability is not solely the plants doing nor has it evolved to benefit humans. Legumes owe their ability to turn a gas into food to a symbiotic relationship with special soil bacteria known collectively as "rhizobia." The legumes produce special root structures called "nodules" to house these bacteria. In return for nitrogen, the bacteria receive carbohydrates and other organic compounds. The nature of this relationship may seem pretty straight forward but, as with anything in nature, the closer we look the more interesting things get. As it turns out, rhizobia also play a role in plant defense.

When a team of researchers began raising Crotalaria, a genus of legume native to Africa, they noticed something strange. Plants that were not inoculated with rhizobia didn't produce nodules nor were they producing any of the alkaloid chemicals that defend them from herbivores. Even adding artificial nitrogen to the soil didn't stimulate the plants to produce their chemical cocktails. Something was going on here and it would seem that the missing bacteria were the key to the puzzle. 

Indeed, only after the plants were inoculated with their native rhizobia did they begin producing nodules and eventually the defensive alkaloid compounds. Could it be that the bacteria produce these chemicals for the plant? 

Not quite. As it turns out, the area of biosynthesis for these defense compounds happens to be in the root nodules that house the rhizobia. The rhizobia trigger the production of the nodules, which in turn triggers the production of the alkaloids. From there, the plant can export them to above-ground structures as a means of defense. The bacteria are simply a key that unlocks a genetic pathway for defense. Seeing as the alkaloids are, in part, made from nitrogenous molecules, this is not too surprising. There is no sense in trying to make these compounds if the chemical ingredients aren't there. This research serves as further evidence of how complex the microbiome can be. 

Photo Credit: Dick Culbert - Wikimedia Commons

Further Reading:

http://www.pnas.org/content/early/2015/03/13/1423457112

Moss Matriarchy

Photo by Wolfram Sondermann licensed under CC BY-ND 2.0

Mosses have been around for a long time. They also retain some interesting features of early land plants. Like their algal precursors, mosses have motile sperm that must literally swim their way to a female gamete. Of course, this process requires water. For some mosses, living on land makes reproduction difficult, even at the scale of a few centimeters. Distance is not the friend of diminutive, sexually reproducing mosses.

There are some groups of mosses that have evolved an interesting way around the issue of distance. Though it occurs in plenty of other genera, I would like to focus attention on one genus in particular, the Dicranum mosses. You can find these hairy-looking mosses growing in tufts or mats in forests throughout North America. Like all bryophytes, they exhibit an alternation of generations. The green gametophytes house the sexual organs and, after fertilization, give rise to the stalked sporophytes that produce and disseminate their spores. 

An inspection of Dicranum patches in the wild may reveal that all of the gametophytes seem to be female. Despite this observation, there would seem to be no shortage of sporophyte stalks poking above the mat. How is this possible? How does sperm make it from some undisclosed male population to fertilize the eggs of these entirely female mats? The answer is to be found only after you observe the females under a microscope. 

Dwarf males growing on the stem tomentum of Dicranum polysetum. Photos: L. Heden€ as [SOURCE]

Under magnification, you will notice that many of the female gametophytes appear to have hairy little outgrowths scattered around their tiny leaves. Under a higher powered lens you may then notice that these hairy outgrowths contain antheridia, the sperm producing organs of males. What is going on here? Are these mosses hermaphroditic? Nope! What you are seeing are indeed the males of this species. 

Spores of Dicranum don't start out as either sex. Instead, their fate in the environment determines what they eventually develop into. If a spore makes it to new terrain, it will become a female. Females are larger and can handle the rigors of establishing new territory. If a spore lands on another clump of moss, something different happens. The female gametophytes emit hormones which direct the development of that spore into one of these dwarfed males. Settled in among a forest of females, this tiny male individual is now primed and ready to release sperm. They are essentially live-in sperm donors.

For this genus, it doesn't make sense fore males to grow into full blown adults in such situations. The bigger a male gets, the more distance separates his sperm from the eggs of females. A reduction in size allows the males to insert themselves into colonies made entirely of females to serve as the reproductive agent for that grouping. Quite a fascinating life history trait if you ask me. Mosses have also been at the survival game much longer than pretty much all other forms of life we encounter on land. I think it goes without saying that they certainly deserve a greater recognition. 

Photo Credit: [1] [2]

Further Reading: [1] [2]

Unlikely Allies

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

On the Balearic Islands of Spain, an interesting relationship has developed between a plant and an animal. What's more, this relationship seems to have developed relatively recently in the history of these two species. The players in this story are the dead horse arum (Helicodiceros muscivorus) and an unsuspecting lizard known as Lilford’s wall lizard (Podarcis lilfordi).

Podarcis lilfordi is a lot like other fence lizards. They spend their days basking in the sun’s warmth and hunting for insect prey. They also have a tendency to feed on nectar and pollen, making them important pollinators of a handful of plant species around the island. For the dead horse arum, however, its not about pollination.

Like most members of its family, the dead horse arum relies on trickery for sex. As its common name suggests, the dead horse arum both looks and smells like rotting meat. Unsuspecting flies looking for a meal and a place to lay their eggs find the dead horse arum quite attractive in this regard. The plant even steps up its game a bit by producing its own heat. This helps volatilize its smell as well as to make it a cozy place worth investigating. Studies have found that during the peak flowering period, the inflorescence can be upwards of 24 °C (50 °F) warmer than its surroundings.

Photo by Marina Sanz Biendicho licensed under CC BY 2.0

As one would expect, this has caught the attention of the cold blooded lizards. Enticed by the heat source, lizards basking on the spathe quickly realize that the plant is also a great place to hunt. Flies attracted to and trapped by the flowers make an easy meal. On the surface this would seem counterproductive for the dead horse arum. What good is an animal hanging around that eats its pollinators?

The relationship doesn't end here though. At some point in recent history, a handful of lizards figured out that the seeds of the dead horse arum also make a great meal. This behavior quickly spread through the population to the point that Podarcis lilfordi regularly break open the seed heads and consume the fleshy berries within. Here's the catch, seeds that have passed through a lizards gut are twice as likely to germinate.

Researchers have been studying this interaction since 1999. Since then, the dead horse arum has gone from being relatively rare on the island (~5,000 individuals per hectare) to a density of roughly 30,000 individuals per hectare during the 6 year span of the study! Even though the lizards eat their pollinators, the dead horse arums of Aire Island have nonetheless benefited from interactions with their cold blooded companions.

Sadly, this novel relationship may not last too long. The introduction of cats and rats to the islands has drastically reduced the population of these lizards to the point that the IUCN has listed them as an endangered species. Research will be needed to see if the dead horse arum follows in their wake.

Photo Credit: [1] [2]

Further Reading: [1] [2]

Bryophytes

Lophocolea heterophylla

A moss in the genus Anomodon

Radula spp.