Seed Shattering Lost – The Story of Foxtail Millet

For a plant to disperse its seeds, it must first let go of them. Sounds obvious, but it is a key step in the dispersal process and an act that is actually coded in a plant’s DNA. As fruits ripen and seeds mature, an abscission layer is formed that separates the seed-bearing fruits from the plant. No longer attached to their parents, seeds are left to their own devices. If all goes well, they will find themselves in a suitable location where they can germinate and grow into a whole new plant, fully equipped to make seed babies of their own.

The releasing of mature seeds is known as shattering, a term most commonly used in reference to grasses and plants with dehiscent seed pods (i.e. fruits that split open when ripe, such as those in the bean and mustard families). In grasses, seeds form along a central stem called a rachis. As the seeds ripen, they separate from the rachis and drop from the plant. In some cases, the rachis is brittle and a section of it breaks off with each seed that falls.

Seed shattering is not a desirable trait when it comes to food crops. It’s easy to see how yields can be poor if seeds disperse before they are harvested. Thus, an essential step in domesticating certain agricultural crops was selecting plants that lacked this particular trait. Instead of dropping mature seeds, such plants hold on to them, making them easy to collect. A simple and naturally occurring mutation in the genes of these plants allowed early farmers to select varieties that were more ideal for agriculture than their wild progenitors.

Genetic studies of agricultural crops have located genes in a number of species that code for seed shattering, confirming that domestication in many cases involved selecting plants with this gene turned off. A recent study, published in Nature Biotechnology (October 2020), took a different route in locating this gene, looking instead at a weedy, wild relative of a crop that was domesticated at least 8000 years ago. Green foxtail (Setaria viridis) is the wild antecedent of foxtail millet (Setaria italica), a crop that, while still commonly grown for food in parts of Asia, is mostly grown for hay, silage, and bird seed in North America. Recently, interest in foxtail millet and other millets (a term used to refer to the grains of several different species of grasses) is on the rise due to the ability of these crops to tolerate drought and heat.

Illustration of three Setaria species from Selected Weeds of the United States (Agriculture Handbook No. 366) published in 1970

Setaria viridis is an abundant, widespread weed adapted to human disturbance. It’s of Eurasian origin but has been present in North America since the early 1800’s and was likely introduced both intentionally and accidentally. It’s an annual grass with prominent, bristly flowerheads that are easily recognizable and the reason for its common name, green foxtail. A handful of other closely related, similar-looking species are also common weeds in North America. Due to useful traits including its short life cycle, small genome, and self-fertility, S. viridis has been used frequently as a model species to carry out a variety of scientific studies. The study referred to above aimed to further enhance the use of green foxtail, particularly when it comes to crop science.

Researchers traveled across the United States collecting nearly 600 samples of green foxtail in order to better understand its genome. They found that the North American population of green foxtail is composed of multiple introductions and that, as the species has followed humans around, it has quickly adapted to diverse climates found across the continent. In examining the genome, they were able to identify the genetic underpinnings for three traits that have importance to agriculture: response to climate, leaf angle (which is used as a predictor of yield in grain crops), and seed shattering.

foxtail millet (Setaria italica) via wikimedia commons

The seed shattering gene – which the researchers named Less Shattering 1 (SvLes1) – was an especially interesting discovery. When compared to the orthologous gene found in foxtail millet, they found that a frameshift mutation had caused a disruption in the gene, turning it off. Using CRISPR (a gene editing tool) they were able to recreate a similar interruption in green foxtail, which resulted in a loss of seed shattering similar to that of foxtail millet. It became clear that selecting plants with this mutation was an essential step in the domestication of this ancient grain.

An excerpt about seed shattering from Fruit from the Sands by Robert N. Spengler III: 

In many of the world’s domesticated grains, especially those from the founder crops of southwest Asia (i.e. wheat and barley), the earliest phenotypical trait of domestication that archaeobotanists look for is a tough rachis, the small stem by which an individual grain or small cluster of grains is attached to the ear. In their wild form, most grains are programmed to detach easily after the grain ripens; however, in domesticated cereals, the grains remain attached to the ear throughout the harvesting process. This change is an inadvertent result of human harvesting with sickles: as people reap their harvest, the grains with a brittle rachis are dropped and those with a tough rachis are collected, stored, and replanted for successive harvests.

Further Reading:

Tea Time: Lemon Balm Tea

Cooler weather has me thinking about hot tea again. This time around I decided to go with something I’ve already tried and know that I like. Despite the fact that lemon balm can be quite abundant and readily available, I don’t really drink it that often. Yet, considering claims made regarding its calming nature, this is definitely the year to have it.

lemon balm (Melissa officinalis)

Melissa officinalis is an herbaceous perennial native to the Mediterranean Basin and beyond. It has been widely planted outside of its native range and has become naturalized – some might say weedy – in many parts of the world. It self-sows easily and also spreads readily via stolons and/or rhizomes. It isn’t picky about soil type and grows well in both sun and part shade. Lemon balm is in the mint family and acts in a similarly aggresive way to some of its relatives, but luckily isn’t nearly as tenacious as mint in its tendency to dominate a garden bed.

The leaves of lemon balm have a wrinkled appearance, are triangular or wedge-shaped with toothed margins, and are arranged oppositely on square stems up to three feet tall. Small, white or pale yellow (sometimes pale pink) flowers are inconspicuous and produced in the axils of leaves. They are often sparse enough to be hardly noticeable. This plant’s aesthetic appeal is all about its pleasant and prolific green foliage. Yet, despite the simplicity of its flowers, lemon balm is known for being attractive to bees and is often propagated specifically to feed honeybees. In fact, the genus name Melissa apparently means honeybee in Ancient Greek.

lemon balm flower

The leaves of lemon balm can be consumed fresh or dried and have a number of other uses besides tea. They have a sweet, lemon-like scent and, like so many other herbs with a long history of human use, have a wide array of medicinal claims associated with them. Many sources agree on lemon balm’s ability to calm the nerves, reduce stress and anxiety, and fight off insomnia. According to The Herb Society of America’s Essential Guide to Growing and Cooking with Herbs, lemon balm “has been used as a relaxing agent and as an aid to restful, nightmare-free sleep.” Sounds like I could use more lemon balm in my life.

dried lemon balm leaves

Lemon balm tea can be made with either fresh or dried leaves, but fresh leaves seem to make a more flavorful tea. I had only tried tea made from dried leaves until recently and have decided that I prefer fresh leaves. Simply harvest a few leaves, cut or tear them apart to release the lemony flavor, place them in a cup, and cover them in hot water. Some recipes (like this one) suggest adding honey, while others mix lemon balm with additional herbs known for their lemon-like flavor or relaxing nature (lemon thyme and lemon verbena, for example). Sierra was immediately taken by lemon balm tea when she tried it – in contrast to her experience with violet leaf tea – and even said it was right up there with her preferred black teas. I’m not surprised, as it is one of my favorite teas as well.

lemon balm tea made with freshly harvested leaves

More Tea Time Posts on Awkward Botany:

A Few More Snags Near Ketchum

Nearly a year has passed since Sierra and I took a trip to Ketchum, Idaho and I reported on some of the snags we encountered there. After months without a break, we finally had the chance to get away for a few days, and since we were desperate for some time off and a change of scenery, we couldn’t turn it down. Plus, we were heading back to Ketchum, so I knew I’d get to check out a few more snags. I was stoked.

I’m obsessed with trees, and my preference is for live ones (generally speaking), but dead trees are certainly gaining in popularity. After all, a dead tree isn’t truly dead. As its corpse slowly rots, it continues to harbor and support life inside and out in a substantial way. Forests need dead trees just as much as they need live trees. Plus, ecology aside, dead trees are no less photogenic than any other tree.

Death isn’t all bad. New life springs from decay. Given our current state of affairs, we need this reminder, and snags offer it in spades. As Sierra and I pulled up to the Apollo Creek trailhead, we looked out onto a section of forest that had clearly been ravaged by fire in the not too distant past. Acres of standing and fallen burned out trees bore witness to this fact. Yet among the dead, life flourished, as dozens of songbirds actively foraged on and around the charred trees. They were there for the insects that were feeding on the dead wood, fueling themselves for fall migration. In the spring, when the birds return, some of them may even nest in the cavities of the dead trees. They will feed again on the insects and raise up a new generation of songbirds that will do the same. In and among snags there are myriad examples just like this, showing us the countless ways in which death supports new life.

What follows is a small sampling of the snags we encountered this time around on our trip to Ketchum.

post-fire snag among many other snags

a series of cavities in a post-fire snag

snag surrounded by live trees

three new snags

fallen snag

broken snag

new tree emerging from a nurse stump

not a snag, but one of many lupines we saw flowering along Apollo Creek Trail

Weeds of Boise: Ahavath Beth Israel Synagogue Garden

Anyone who has maintained a garden or small farm knows that with all the work it takes to keep up on the garden itself, outlying areas can quickly become overtaken by weeds. Low on the list of priorities, areas outside of our garden borders are ideal locations for wild urban vegetation to thrive. Pulling all the weeds within the garden is a big enough task as it is; thus, weeds out of our reach are left to their own devices, occasionally getting mown down by a string trimmer or brush mower (if time allows), but otherwise living largely unscathed. And so, places such as these are excellent for familiarizing oneself with our wild urban flora.

I found an example of this scenario at the Ahavath Beth Israel Synagogue Garden in Boise, Idaho. This community garden is a partnership between Congregation Ahavath Beth Israel (CABI) and Global Gardens, providing refugees in the area an opportunity to grow food for their families and participate in community activities.

When I visited this site, it was clear that the weeds on the edge of the garden had been mowed down at some point. New plants had popped up after the fact while others were in the process of recovering from the “haircut” and putting on new, shrubbier growth. The mowing and the fact that it was late in the summer made identifying remnants of earlier weeds too difficult to bother. Most of the weeds that I did find were either summer annuals or perennials. A visit in the spring would reveal an entirely different cast of characters.

I stayed on the border of the garden, not wanting to invade anyone’s plot or snoop around too much. The point of the visit was to highlight weeds found outside of the borders of a garden anyway. I would imagine that, since the garden is used to grow annual fruits and vegetables, most of the weeds in the beds would be annuals as well. Longer-lived weeds don’t generally tolerate regular disturbance and instead find refuge in unkept areas outside of cultivation.

Below are a few photos from the site along with a preliminary list of the weeds that I found.

salsify (Tragopogon dubius)

puncture vine (Tribulus terrestris)

field bindweed (Convolvulus arvensis)

Siberian elm (Ulmus pumila)

common mallow (Malva neglecta)

black medic (Medicago lupulina)

Weeds found at the Ahavath Beth Israel Synagogue Garden:

  • Amaranthus spp. (pigweed)
  • Bassia scoparia (kochia)
  • Chenopodium album (lamb’s quarters)
  • Chondrilla juncea (rush skeletonweed)
  • Convolvulus arvensis (field bindweed)
  • Conyza canadensis (horseweed)
  • Digitaria sanguinalis (crabgrass)
  • Epilobium brachycarpum (tall annual willowherb)
  • Euphorbia maculata (spotted spurge)
  • Hordeum jubatum (foxtail barley)
  • Lactuca serriola (prickly lettuce)
  • Malva neglecta (common mallow)
  • Medicago lupulina (black medic)
  • Oenothera biennis (common evening-primrose)
  • Plantago lanceolata (narrowleaf plantain)
  • Polygonum aviculare (prostrate knotweed)
  • Rumex crispus (curly dock)
  • Setaria sp. (foxtail)
  • Sonchus sp. (sow thistle)
  • Taraxacum officinale (dandelion)
  • Tragopogon dubius (salsify)
  • Trifolium pratense (red clover)
  • Ulmus pumila (Siberian elm)
  • Verbena bracteata (prostrate vervain)

Like all posts in the Weeds of Boise series, this will be updated as I identify and photograph more of the weeds found in this location.

Flowers Growing Out of Flowers (Things Are Getting Weird Out There)

I’m sure that anyone living through the events of 2020 would agree, these are truly wild times. So, when I stumbled across some purple coneflowers that appeared to be growing flowers out of flowers, I thought to myself, “Of course! Why not!?!” The world is upside down. Anything is possible.

As it turns out, however, this phenomenon occurs more frequently than I was aware. But it’s not necessarily a good thing, particularly if you’re concerned about plant health. We’ll get to that in a minute. First, what’s going on with these flowers?

Flowers in the aster family are unique. They have the appearance of being a single flower but are actually a cluster of two types of much smaller flowers all packed in together. Purple coneflower (Echinacea purpurea) is a great example of this. Its flower heads are composed of dozens of disc flowers surrounded by a series of ray flowers. The minuscule disc flowers form the cone-like center of the inflorescence. The petals that surround the cone are individual ray flowers. This tight cluster of many small flowers (or florets) is known as a composite. Sunflowers are another example of this type of inflorescence.

Flowers are distinct organs. Not only are they the reproductive structures of flowering plants, but unlike the rest of the plant, they exhibit determinate growth. Flowers are, after all, plant shoots that have been “told” to stop growing like other shoots and instead modify themselves into reproductive organs and other associated structures. Unlike other shoots, which continue to grow (or at least have the potential to), a flower (and the fruit it produces) is the end result for this reproductive shoot. This is what is meant by determinate growth. However, sometimes things go awry, and the modified shoots and leaves that make up a flower don’t develop as expected, producing some bizarre looking structures as a result.

An example of this is a double flower. Plants with double flowers have mutations in their genes that cause disruptions during floral development. This means that their stamens and carpels (the reproductive organs of the flowers) don’t develop properly. Instead, they become additional petals or flowers, resulting in a flower composed of petals upon petals upon petals – a look that some people like, but that have virtually nothing to offer the pollinators that typically visit them. Because of their ornamental value, double-flowered varieties of numerous species – including purple coneflower – can be found in the horticultural trade.

double-flowered purple coneflower

Genetic mutations are one way that odd looking flowers come about. It is not the cause, however, of the freak flowers that I recently came across. What I witnessed was something called phyllody and was the result of an infection most likely introduced to the plant by a leafhopper or some other sap-sucking insect. Phyllody, which has a variety of causes, is a disruption in plant hormones that leads to leaves growing in place of flower parts. As a result, the flowers become sterile and green in color. In the case of purple coneflower, leafy structures are produced atop shoots arising from the middle of ray and/or disc florets. In other species, shoots aren’t visible and instead the inflorescence is just a cluster of leaves. In a sense, the reproductive shoot has returned to indeterminate growth, having switched back to shoot and leaf production.

Phyllody can have either biotic or abiotic causes. Biotic meaning infection by plant pathogens – including certain viruses, bacteria, and fungi – or damage by insects. Abiotic factors like hot weather and lack of water can result in a temporary case of phyllody in some plants. Phyllody plus a number of other symptoms made it clear that the purple coneflower I encountered had a fairly common disease known as aster yellows. This condition is caused by a bacterial parasite called a phytoplasma, and is introduced to the plant via a sap-sucking insect. It then spreads throughout the plant, infecting all parts. The phyllody was a dead give away, but even the flowers that weren’t alien-looking were discolored. The typical vibrant purple of the ray flowers was instead a faded pink color. The flowers that had advanced phyllody – along with the rest of the plant – were turning yellow-green.

This inflorescence isn’t exhibiting phyllody yet, but the purple color in the ray flowers is quickly fading.

Hundreds of plant species are susceptible to aster yellows, and not just those in the aster family. Once a plant is infected with aster yellows, it has it for good and will never grow or reproduce properly. For this reason, it is best to remove infected plants from the garden to avoid spreading the infection to other plants. As cool as the flowers may look, infected plants just aren’t worth saving.

Further Reading: 

Party Time for Puncture Vine During COVID Times

In spite of a global pandemic, the third annual Boise Goathead Fest took place last Saturday in Boise, Idaho. In order to make it happen, organizers had to think creatively, completely reenvisioning the event in order to keep the community safe and healthy. This, of course, meant no giant bike parade and no large gathering in the park. Instead, members of individual households embarked on their own socially-distanced bike rides, meeting up in small groups for a wide variety of mini-events across town. An online radio show made possible by Radio Boise provided the day’s soundtrack and kept us all up to date with regular live announcements.

On Saturday morning, Sierra and I decorated our bikes and ourselves and headed out on our two-person bike parade. Our first stop was the Goathead Monster’s Lair located in the alley behind Boise Bicycle Project. There we picked up food, beverages, and a map. The list of places to go and things to see was extensive. At our relaxed pace, there was no way we were going to see it all, which wasn’t really our goal anyway. Times are strange, and we were just happy to be out in the world taking part in another Goathead Fest.

Entrance to the Goathead Monster’s Lair

2020 COVID Edition Boise Goathead Fest Map

Learning some facts about goatheads with Mr. A on guitar and violin

Sierra and I next to one of many goathead-themed art installations featured around town

Bikes were allowed at Idaho Botanical Garden for one hour only – a Goathead Fest exclusive!

Not only is the Goathead Fest a celebration of bicycles and community and an opportunity to raise money for pedal-powered non-profits in the Treasure Valley, it’s also a way to bring awareness to a noxious weed responsible for countless flat tires year in and year out. Tribulus terrestris is the bane of bicyclists. Its round, spiky fruits lie in wait to royally ruin our rides. Thanks to collection efforts that take place in the months leading up to the Goathead Fest, thousands of pounds of puncture vine are removed from our streets each year.

This year, another round, spiky ball threatened to ruin our ride. This threat is much smaller and considerably more damaging. Invisible to the naked eye, it has infected hundreds of members of our community, killing many of them, much like it has done in communities across the world. With the threat of COVID-19 looming over our heads, the Boise Goathead Fest felt and looked much different. We masked up and tried to keep our distance from each other. We dispersed ourselves across the city and enjoyed the company of much smaller crowds. As someone who, apart from work and occassional trips to the store, has largely removed himself from social gatherings, I felt nervous to be out. Thanks to the thoughtfulness and awareness of Goathead Fest organizers, my fears were largely soothed. It was important for me to, once again, be together with Boise’s bicylce community and feel a renewed sense of hope for the future.

We are all looking forward to the day when the only round, spiky ball that threatens to keep us off our bikes are those blasted goatheads, and even those – if we keep at it – might someday be a thing of the past.

More Party Time for Puncture Vine on Awkward Botany

Awkward Botanical Sketches #4: Boise Goathead Fest Edition

Covid-19 be damned, Boise Goathead Fest is happening in 2020. However, since we’re in the middle of a pandemic and the number of infections in Idaho have been far greater than we’d like them to be, this beloved, summertime event (now in its third year) is going to look quite a bit different this time around. No giant bicycle parade snaking through downtown Boise, no big gathering in the park to celebrate bicycles and recogonize all who helped pull goatheads across the Treasure Valley, and (I have to assume) no bike sumo. But we’re still going to decorate our bikes and ourselves like a noxious weed and go for a bike ride, and even though we won’t all be able to gather together in one spot, the sentiment will undoubtedly be the same.

I’m a big fan of the Goathead Fest, and not simply because I love bicycles and bike-culture. In fact, it’s mostly because a plant – while despised by all who ride bikes in this area – takes centerstage in the celebration. Not too many plants get this kind of attention. And sure, it may only find itself in the spotlight because of its bad behavior, but at least it has people paying more mind to green things.

In anticipation of this year’s Goathead Fest, I decided to make a few attempts at drawing Tribulus terrestris. Goathead art has played a big part in the festivities since year one, and this year is no exception. In a normal year, all of the artwork would be displayed together in Cecil D. Andrus Park. This year, pieces of art will be displayed around town for us all to happen upon as we embark on our socially distanced bike rides. However, you won’t see any of my artwork out there (for good reason). Maybe someday (one can dream, I guess). Until then, I’ll include a few of my awkward attempts below.

the flower of Tribulus terrestris

an attempt to color the flower of Tribulus terrestris

goathead nutlets #1

goathead nutlets #2

Tribulus terrestris leaf rubbing

Goathead Monster #1

Goathead Monster #2

More Awkward Botanical Sketches: 

Book Review: The Gyroscope of Life

Gyroscopes are entertaining toys and incredibly useful tools. They retain their balance and resist changes to their orientation as long as their flywheel is spinning. As the flywheel slows or stops, the gyroscope wobbles out of control and ultimately quits. Considering their design and function, it’s easy to find parallels between gyroscopes and living systems. Consistent energy inputs keep living things alive. Changes can bring imbalance; major disruptions can lead to death. There is a reason we often describe the natural world as a sort of balancing act. It is the work of an ecologist to make sense of this balancing act. The better we understand it, the more equipped we are to protect it and operate responsibly within it.

It is through this lens that David Parrish writes about the biological world in The Gyroscope of Life, a book that Parrish refers to as “a love song to the field of biology.” Parrish has spent much of his life observing and studying the natural world and, as professor emeritus of Crop and Soil Environmental Sciences at Virginia Tech, undoubtedly shared much of what he presents in his book with countless students over the years. The Gyroscope of Life reads like part memoir and part last lecture, and is the work of someone who has an obvious passion for science and nature.

Parrish spends the first few chapters of his book writing mostly about his life and how he came to be a biologist. He acknowledges his privelege – “born male, white, and American in an era where each of those attributes provided me major advantages” –  having essentially been placed on third base from the start, “well down the third base line.” An aspiring zoologist turned botanist, he spent his early years in graduate school studying seeds and seed dormancy. It’s a topic that obviously interests him, as several pages of the book are spent considering what’s going on inside of a seed. “Seeds provide the widest-spread examples of suspended life,”  Parrish says. Are they alive or dead or neither?

Two additional, major life events play a prominent role in the arc of Parrish’s book. One being his break from organized religion and the other his battle with advanced prostate cancer. He grew up in an orthodox Christian home with a very literal understanding of the Bible. His education put him at odds with what he was taught growing up about (among other things) the age of the earth and its creation. Eventually he came to understand that science and religion “exist in separate non-overlapping spheres – the physical and the metaphysical.” He doesn’t necessarily see science and religion as being inherently at odds with each other, but his understanding of science makes it difficult to “find resonance in religion” due to the “cacophony of dissonance” it offers.

In addressing his prostate cancer, Parrish underwent an operation that gave him a newfound perspective on gender. Freed from “testosterone poisoning,” he was able to more fully consider sex and gender from a biological perspective, which he says he had been doing for decades prior to the operation. He spends a good portion of the book “demystifying sex and gender.” One compelling example he offers involves avocado flowers, which actually change gender over time, a phenomenon known as synchronous dichogamy.

avocado flowers (Persea americana) via wikimedia commons

Over the course of its pages, The Gyroscope of Life covers a significant number of topics in the fields of biology and ecology. It’s a relatively short book, but as it careens through such wide-ranging material, it does so in an approachable and suprisingly succint manner. Parrish’s sense of humor, which doesn’t waver despite how bleak the discussion sometimes gets, helps carry the story along and keeps things interesting. Parrish covers evolution (“[Biologists] argue that, if evolution didn’t happen, it should.”), taxonomy (“the name for naming things”) and sytematics, ecological niches (“[humans] are essentially living niche-free and ecosystemless”), domestication, and so much more. The last chapter is spent discussing agroecosystems (“the organisms and abiotic environment that interact in a human-managed agricultural setting”), a topic he spent much of his career studying.

The underlying message of this book, as I see it, is a simultaneous celebration for life on earth and a concern for the direction things are going considering how humans have managed things. Parrish has some admonition for humans in light of how we’ve treated our home planet, but he isn’t too heavy-handed about it. Overall, reading the book felt like sitting in on a lecture given by a friendly and dynamic professor who has obviously given a lot of thought to what he has to say.

Check out the following video to see David Parrish describe the book in his own words.

More Book Reviews on Awkward Botany:

The Hidden Flowers of Viola

Violas keep a secret hidden below their foliage. Sometimes they even bury it shallowly in the soil near their roots. I suppose it’s not a secret really, just something out of sight. There isn’t a reason to show it off, after all. Showy flowers are showy for the sole purpose of attracting pollinators. If pollinators are unnecessary, there is no reason for showy flowers, or to even show your flowers at all. That’s the story behind the cleistogamous flowers of violas. They are a secret only because unless you know to look for them, you would have no idea they were there at all.

Cleistogamy means closed marriage, and it describes a self-pollinating flower whose petals remain sealed shut. The opposite of cleistogamy is chasmogamy (open marriage). Most of the flowers we are familiar with are chasmogamous. They open and expose their sex parts in order to allow for cross-pollination (self-pollination can also occur in such flowers). Violas have chasmogamous flowers too. They are the familiar five-petaled flowers raised up on slender stalks above the green foliage. Cross-pollination occurs in these flowers, and seed-bearing fruits are the result. Perhaps as a way to ensure reproduction, violas also produce cleistogamous flowers, buried below their leaves.

an illustration of the cleistogamous flower of Viola sylvatica opened to reveal its sex parts — via wikimedia commons

Flowers are expensive things to make, especially when the goal is to attract pollinators. Colorful petals, nectar, nutritious pollen, and other features that help advertise to potential pollinators all require significant resources. All this effort is worth it when it results in the ample production of viable seeds, but what if it doesn’t? Having a method for self-pollination ensures that reproduction will proceed in the absence of pollinators or in the event that floral visitors don’t get the job done. A downside, of course, is that a seed produced via self-pollination is essentially a clone of the parent plant. There will be no mixing of genes with other individuals. This isn’t necessarily bad, at least in the short term, but it has its downsides. A good strategy is a mixture of both cross- and self-pollination – a strategy that violas employ.

The cleistogamous flowers of violas generally appear in the summer or fall, after the chasmogamous flowers have done their thing. The fruits they form split open when mature and deposit their seeds directly below the parent plant. Some are also carried away by ants and dispersed to new locations. Seeds produced in these hidden flowers are generally superior and more abundant compared to those produced by their showy counterparts. People who find violas to be a troublesome lawn weed – expanding far and wide to the exclusion of turfgrass – have these hidden flowers to blame.

That being said, there is a defense for violas. In the book The Living Landscape by Rick Darke and Doug Tallamy, Tallamy writes: “Plants such as the common blue violet (Viola sororia), long dismissed by gardeners as a weed, can be reconstituted as desirable components of the herbaceous layer when their ecosystem functionality is re-evaluated. Violets are the sole larval food source for fritillary butterflies. Eliminating violets eliminates fritillaries, but finding ways to incorporate violets in garden design supports fritillaries.”

sweet violet (Viola odorata)

In my search for the cleistogamous flowers of viola, I dug up a sweet violet (Viola odorata). I was too late to catch it in bloom, but the product of its flowers – round, purple, fuzzy fruits – were revealed as I uprooted the plant. Some of the fruits were already opening, exposing shiny, light brown seeds with prominent, white elaiosomes, there to tempt ants into aiding in their dispersal. I may have missed getting to see what John Eastman calls “violet’s most important flowers,” but the product of these flowers was certainly worth the effort.

Fruits formed from the cleistogamous flowers of sweet violet (Viola odorata)

Up close and personal with the fruit of a cleistogamous flower

The seeds (elaiosomes included) produced by the cleistogamous flower of sweet violet (Viola odorata)

See Also:

Revisiting the Moon Tree

I first learned about Moon Trees in the fall of 2015. One of the trees – a loblolly pine – had been planted at an elementary school just down the street from where I was living at the time. It wasn’t a new thing – it was planted back in 1977, during the period when most other Moon Trees where being planted around the country and the world – but because it wasn’t doing too well, it was in the news. Members of the community, concerned about its long-term survival, were pitching in to help keep it alive. Once I was made aware of it, I also became concerned and decided to go check on it. I even wrote a post about it, which you can read here.

Now that nearly 5 years have passed, I figured I should go check on it again. I hadn’t heard any more news about it, so I assumed it was still hanging in there, but who knows? Maybe not. Since I was going to be on that side of town for Father’s Day, I made plans to stop by. My dad hadn’t seen the tree yet, so he decided to join me.

As we approached Lowell Elementary on our bikes, I was half-expecting the tree to be gone. It was in pretty sad shape when the community stepped in to help it. Braced for this possibility, I anxiously peered down the street as we biked closer. When the tree came into view, I felt relief and announced, “There it is!”

All this time later, it still looks a little rough. The majority of its bark remains largely obscured by crusty, dried up sap, and its canopy isn’t as full as it likely would be if it was a picture of health. But it’s alive and, surprisingly enough, still growing taller, reaching for the moon.

Any loblolly pine would feel out of place in Idaho – it’s a species whose distribution spans the southwest region of the United States, which is starkly different from the northwest – however, this individual in particular is an anomaly. The seed it sprouted from took a journey into space, circled the moon a number of times and then, as a sapling, was planted in Idaho (of all places). Now, over 40 years later, it stands as a symbol of resilience. Something we could all use right now, I’m sure.

This sign was installed shortly after my original Moon Tree post.

Boise, Idaho’s Moon Tree in June 2020

My dad by the Moon Tree in Boise, Idaho

Me by the Moon Tree in Boise, Idaho

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Was a Moon Tree planted near you? Is it still around? Tell us about it in the comment section below.