Trout Lily Appreciation

This video is a celebration of the white trout lily (Erythronium albidum) and its various spring ephemeral neighbors. We even talk about the threat that invasive species like garlic mustard (Alliara petiolata).

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

Music by
Artist: Botanist
Track:
https://verdant-realm-botanist.bandcamp.com/

Early Spring Ephemerals

Join us as we go in search of some of the earliest spring ephemerals. In this episode we come face to face with the aptly named harbinger of spring (Erigenia bulbosa) and the lovely Hepatica nobilis.

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

Music by
Artist: Stranger In My Town
Track: Air
https://strangerinmytown.bandcamp.com/

Do Yeasts Aid Pollination For the Stinking Hellebore?

Whether they are growing in their native habitat or in some far away garden, Hellebores are some of the earliest plants to bloom in the spring. Hellebore flowers can often be seen blooming long before the snow has melted away. All early blooming plant species are faced with the challenge of attracting pollinators. Though the competition for insect attention is minimal among these early bloomers, only the hardiest insects are out and about on cold, dreary days. It stands to reason then that anything that can entice a potential pollinator would be of great benefit for a plant.

That is why the presence of yeast in the nectar of at least one species of Hellebore has attracted the attention of scientists. The species in question is known scientifically as Helleborus foetidus. The lack of appeal in its binomial is nothing compared to its various common names. One can often find H. foetidus for sale under names like the "stinking hellebore" or worse, "dungwort." All of these have to do with the unpleasant aroma given off by its flowers and bruised foliage. Surprisingly, that is not the topic of this post.

What is more intriguing about the flowers of H. foetidus is that the nectar produced by its smelly green flowers harbors dense colonies of yeast. Yeasts are everywhere on this planet and despite their economic importance, little is known about how they function in nature. For instance, what the heck are these yeast colonies doing in the nectar of this odd Hellebore?

To test this, two researchers from the Spanish National Research Council manipulated yeast colonies within the flowers to see what might be happening. It turns out, yeast in the nectar of H. foetidus actually warms the flowers. As the yeast feed on the sugars within the nectar, their metabolic activity can raise the temperature of the flowers upwards of 2 °C above the ambient. As far as we know, the only other ways in which floral heating has been achieved is either via specific metabolic processes within the floral tissues or by direct heating from the sun. 

In heating the flowers, these yeast colonies may be having serious impacts on the reproductive success of H. foetidus. For starters, these plants are most at home under the forest canopies of central and western Europe. What's more, many populations find themselves growing in the dense shade of evergreens. This completely rules out the ability to utilize solar energy to heat blooms. Additionally, floral heat can mean more visits by potential pollinators. Experiments have shown that bees preferentially visit flowers that are slightly warmer than ambient temperatures. Even the flowers themselves can benefit from that heat. Warmer flowers have higher pollination rates and better seed set.

Bombus terrestris  was one of the most common floral visitors of  Helleborus foetidus.

Bombus terrestris was one of the most common floral visitors of Helleborus foetidus.

Yeast colonies also have their downsides. The heat generated by the yeast comes from the digestion of sugars. Indeed, nectar housing yeast colonies had drastically reduced sugar loads than nectar without yeast. This has the potential to offset many of the benefits of floral warming in large part because bees are good at discriminating. Bees are visiting these blooms as a food source and by diminishing the sugar content of the nectar, the yeast may be turning bees off to this potential source. The question then becomes, do bees prefer heat over sugar-rich food? The authors think there might be a trade-off, with bees preferring heated flowers on colder days and sugar-rich flowers on warmer days.

Helleborus foetidus  flowering before the snow has had a chance to melt!

Helleborus foetidus flowering before the snow has had a chance to melt!

Though the authors found evidence for heating, they did not test for pollinator preference. All we know at this point is that yeast in the nectar significantly warms H. foetidus flowers. Since this piece was originally published, more attention has been paid to the benefits of the heat generated from yeast. Interestingly, researchers found that pollen tube formation was higher for H. foetidus flowers that experienced heat earlier in the season but not for those that experienced heat later on. This response, however, was not due to the warming directly. Instead, it had more to do with bee preference.

As it turns out, bumblebees do in fact prefer to visit heated flowers but their preference is limited to the early periods of flowering when ambient temperatures are still quite low. More bumblebees visiting heated flowers in the early spring equated to more pollen being deposited on the stigma, which in turn led to an increase in pollen tube formation and higher seed set. Later on in the season, when ambient temperatures increased a bit, this positive effect dropped off as bees apparently spent more time foraging elsewhere.

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

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

The Giant Genomes of Geophytes

Canopy plant ( Paris japonica )

Canopy plant (Paris japonica)

A geophyte is any plant with a short, seasonal lifestyle and some form of underground storage organ ( bulb, tuber, thick rhizome, etc.). Plants hailing from a variety of families fall into this category. However, they share more than just a similar life history. A disproportionate amount of geophytic plants also possess massive genomes. 

As we have discussed in previous posts, life isn't easy for geophytes. Cold temperatures, a short growing season, and plenty of hungry herbivores represent countless hurdles that must be overcome. That is why many geophytes opt for rapid growth as soon as conditions are right. However, they don't do this via rapid cell division. 

Dutchman's breeches ( Dicentra cucullaria ) emerging with preformed buds.

Dutchman's breeches (Dicentra cucullaria) emerging with preformed buds.

Instead, geophytes spend the "dormant" months pre-growing all of their organs. What's more, the cells that make up their leaves and flowers are generally much larger than cells found in non-geophytes. This is where that large genome comes into plant. If they had to wait until the first few weeks of spring to start their development, a large genome would only get in the way. Their dormant season growth means that these plants don't have to worry about streamlining the process of cellular division. They can take their time. 

As such, an accumulation of genetic material isn't detrimental. Instead, it may actually be quite beneficial for geophytes. Associated with large genomes are things like larger stomata, which helps these plants better regulate their water needs. The large genomes may very well be the reason that many geophytic plants are so good at taking advantage of such ephemeral growing conditions. 

When the right conditions present themselves, geophytes don't waste time. Pre-formed organs like leaves and flowers simply have to fill with water instead of having to wait for tissues to divide and differentiate. Water is plentiful during the spring so geophytes can rely on turgor pressure within their large cells for stability rather than investing in thick cell walls. That is why so many spring blooming plants feel so fleshy to the touch. 

Taken together, we can see how large genomes and a unique growth strategy have allowed these plants to exploit seasonally available habitats. It is worth noting, however, that this is far from the complete picture. With such a wide variety of plant species adopting a geophytic lifestyle, we still have a lot to learn about the secret lives of these plants.

Photo Credits: [1] [2]

Further Reading: [1]

The Hunt

This week we are going on the hunt for a small member of the carrot family known as the harbinger of spring (Erigenia bulbosa). Along the way we meet a handful of interesting plant species. Will we find our quarry? Watch and find out...

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

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

Facebook: www.facebook.com/indefenseofplants

Tumblr: www.tumblr.com/indefenseofplants

Twitter: @indfnsofplnts

Meeting Blue-Eyed Mary

For some plant species, pictures will never do them justice. I realized this when I first laid eyes on a colony of blue-eyed Mary (Collinsia verna). I was smitten. These lovely little plants lined the trail of a floodplain forest here in central Illinois. It was the blue labellum that first caught my eye. After years of reading about and seeing pictures of these plants, meeting them in person was a real treat. 

C. verna is winter annual meaning its seeds germinate in the fall. The seedlings lie dormant under the leaf litter until spring warms enough for them to start growing. Growth is rapid. It doesn't take long for them to unfurl their first flowers. And wow, what flowers they have! 

DSCN9475.JPG

The bicolored blooms are a real show stopper. The lower lip contrasts starkly with the white top. It's about as close to true blue as a flower can get. Not only are they beautiful, the flowers are marvels of evolution, exquisitely primed for pollination by large, spring-hardy insects. When something the size of a bumble bee lands on the flower, the lower lip parts down the middle, thrusting the reproductive bits up against the abdomen. This plant doesn't take any chances. 

Being an annual, C. verna can only persist via its seed bank. Populations can be eruptive, often appearing in mass after a disturbance clears the forest of competition. Most populations exist from year to year as much smaller patches that slowly build the seed bank in preparation for more favorable conditions in the future. Because of its annual life cycle, C. verna can be rather sensitive to habitat destruction. 

Seeing this plant with my own eyes far exceeded my expectations. It was one of those moments that I couldn't peel myself away from. I love spring ephemerals and this species has skyrocketed to the top of my list. Its beauty is made all the more wonderful by its ephemeral nature. Enjoy them while they last as it may be some time before you see them again. 

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

Toothworts

North America's native toothworts are something worth celebrating. These wonderful little mustards burst into bloom each spring all over moist deciduous forests, putting on a show that lasts only a few weeks. By mid June these little plants are just about ready for dormancy. Coming across a patch of any toothwort species is always a joy, especially after a long winter.

The toothworts were once placed in the genus Dentaria but are now residing in the genus Cardamine. With their four-petaled flowers and long, slender siliques they are unmistakable as members of the mustard family. Probably the most familiar species to most would be the cutleaf toothwort, Cardamine concatenata. Finding it is a good indication that the land has not been too heavily disturbed. It is one of the first species to disappear after heavy human disturbance.

There are a handful of other toothworts that play an important role of at least one lepidopteran species flying around eastern forests, the Virginia white butterfly (Pieris virginiensis). Its larvae feed primarily on the slender toothwort (Cardamine angustata) and the broad leaf toothwort (Cardamine diphylla). Due to severe habitat fragmentation, this butterfly has declined rapidly throughout parts of its range. As forests give way to farmland and sub-developments, the toothworts they raise their young on quickly disappear. Also, populations of the Virginia white are becoming more and more isolated as they will not disperse across fields, roadways, or any other open space. Instead, they must rely on pockets of forest with healthy toothwort populations.

To add insult to injury, the much maligned garlic mustard also finds toothwort habitat to its liking. Aside from crowding out toothworts, garlic mustard is toxic to Virginia white larvae. Sadly, the butterflies will still lay eggs on garlic mustard, dooming the next generation to almost certain death. As forest patches grow smaller and smaller and the native species within them disappear, entire food chains will come crashing down around them. The plight of the Virginia white stands as a stark reminder of why land conservation is a must.

Help monitor for the Virginia white in your area:http://www.leapbio.org/west-virginia-white

Photo Credits: Vicki DeLoach (http://bit.ly/1E1a8sD)

Further Reading:
http://www.fs.usda.gov/Inter…/FSE_DOCUMENTS/fsm91_054237.pdf

http://www.butterfliesandmoths.org/spec…/Pieris-virginiensis

http://images.peabody.yale.edu/…/1…/1994-48(2)171-Porter.pdf

Trillium Morph

Did you know that there is a naturally occurring white morph of Trillium erectum? I was lucky enough this weekend to find this white one growing right next to its red counterpart. An exciting find indeed!

Trillium

image.jpg

Trillium. The very name is synonymous with spring wherever they grow. Even the non-botanically minded amongst us could probably pick one out of a lineup. This wonderful genus holds such a special place in my heart and I anxiously await their return every year. The journey from seed to flowering plant is an arduous one for a trillium and some may take for granted just how much time has elapsed from the moment the first root pushed through the seed coat to the glorious flowers we admire each spring. The story of a Trillium, like any other plant, starts with a seed.

image.jpg

As with many other spring ephemerals, Trilliums belong to that group of plants that utilize ants as seed dispersers. Once underground in an ant midden, a Trillium seed plays the waiting game. Known as double dormancy, their seeds germinate in two phases. After a year underground, a root will appear followed by an immature rhizome and cotyledon. Here the plant remains, living off of the massive store of sunlight saved up in the endosperm for yet another year. Following this second year underground, the plant will throw up its first leaf.

image.jpg

In its fourth year of growth, the Trillium seedling will finally produce the characteristic whorl of 3 leaves we are familiar with. Now the real waiting game begins. Growing for such a short period of time each year and often in shady conditions, Trilliums must bide their time before enough energy is saved up to produce a flower. In an optimal setting, it can take a single Trillium 7 to 8 years to produce a flower. If conditions aren't the best, then it may take upwards of 10 years! Slow and steady wins the race in the genus Trillium. A large population of flowering Trillium could easily be 40 or 50 years old!

image.jpg

Sadly, when you couple this slow lifestyle with their undeniable beauty, you begin to spell disaster for wild trillium populations. A plant that takes that long to germinate and flower isn't the most marketable species for most nurseries and, as a result, Trillium are some of the most frequently poached plants in the wild. Because of their slow growth rate, poached populations rarely recover and small plots of land can quickly be cleared of Trilliums by a few greedy people. Leave wild Trilliums in the wild! 

Further Reading:

http://www.trilliumsunlimited.com/resources/3-1NPJ18-20.pdf

http://www.trilliumresearch.org/

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, a research paper by Frank M. Frey out of Indiana University would suggest otherwise. He chalks it all up to opposing natural selection from herbivores and pathogens.

Say what now? In a 2 year study, Frey has made some amazing discoveries. First, he 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. He found 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". Frey 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. Frey used a multitude of different analytical methods to assess overall fitness of each color morph and his 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. His research found 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 any given area because the more pollinator visits, 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. Frey found that white colored flowers experienced significantly less predation than crimson flowers. Herbivory has serious consequences for Claytonia and 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. Wow!

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, Frey explains that 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 a recent publication by Dr. Robert Warren and Dr. Mark Bradford 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. 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. They 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 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:
http://bit.ly/1J4VnN7

Snowdrops

image.jpg

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. 

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. 

image.jpg

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/

The Vernal Dam Hypothesis

image.jpg

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

Do You Smell Skunk?

Do you smell that?

All around northeastern North America, a strange smell is starting to hang in the air. The skunky odor could easily be mistaken for an actual skunk but it isn't quite that strong. Some say garlic is a more apt description. If you are in a wet area you may notice small chimneys in the snow or what looks like a red and yellow parrot beak poking up from the ground. The smell gets stronger as you bend down to get a closer look. What you are seeing is Symplocarpus foetidus, better known as eastern skunk cabbage.

Skunk cabbage is a true spring wildflower. It is also one of those small groups of plants that can generate their own heat. This aroid can literally melt its way through the snow cover. Skunk cabbage hails from the same family of plants as the titan arum, Araceae. The inflorescence emerges in early spring, oten before the snow (if there is any) has had a chance to melt. Using heat generated via a unique form of metabolic activity, the inflorescence can reach temperatures of 15-25°C (59-77°F).

So, why the heat and smell? Well, if you like to bloom before the snow melts, you better hope you can at least melt through some of it. In deeper areas, skunk cabbage flowers create chimneys in the snow, which helps channel the scent up into the air. Though it may seem surprising, there are in fact insects out and about during the early days of spring. The smell attracts pollinators such as carrion flies and gnats. The heat also aids in volatilizing the odor, thus causing it to spread out farther. By blooming this early, skunk cabbage assures that its flowers get a majority of the attention.

After flowering is finished, the plant then throws up its large, green, elephant ear leaves. They are unmistakable. As the plant continues to grow throughout the season, its roots contract into the soil, digging the plant deeper and deeper. In effect, skunk cabbage grows down, not up. This is advantageous if you live in an area prone to flooding. The deeper you go, the harder it is to get pulled out.

I love this plant. It is wonderful to see its blooms poking up from underneath the snow. After so many months of drab colors and short days, this harbinger of spring is a breath of fresh, albeit stinky, air.

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