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: 

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:

The Dispersal of Ancient and Modern Apples by Humans and Other Megafauna

Crop domestication often involves selection for larger fruits. In some crops, humans took plant species with relatively small fruits and, over many generations of artificial selection, developed a plant with much larger fruits. Consider giant pumpkins as an extreme example. Yet in the case of apples, relatively large fruits already existed in the wild. Producing larger apples happened quickly and, perhaps even, unconsciously. Apples were practically primed for domestication, and as Robert Spengler explains in a paper published last year in Frontiers in Plant Science, looking back in time at the origins of the apple genus, Malus, can help us understand how the apple we know and love today came to be.

Apples are members of the rose family (Rosaceae), a plant family that today consists of nearly 5000 species. According to the fossil record, plants in the rose family were found in large numbers across North America as early as the Eocene (56 – 33.9 million years ago). They were present in Eurasia at this time as well, but Spengler notes, “there is a much clearer fossil record for Rosaceae fruits and seeds in Europe and Asia during the Miocene and Pliocene (20 – 2.6 million years ago).” Around 14 million years ago, larger fruits and tree-form growth habits evolved in Rosaceae subfamilies, giving rise to the genera Malus and Pyrus (apples and pears). Small, Rosaceae fruits were typically dispersed by birds, but as Sprengler writes, “it seems likely that the large fruits [in Malus and Pyrus] were a response to faunal dispersers of the late Miocene through the Pliocene of Eurasia.” Larger animals were being recruited for seed dispersal in a changing landscape.

Glacial advances and retreats during the Pleistocene (2.6 million – 11,700 years ago) brought even more changes. Plants with effective, long distance seed dispersal were favored because they were able to move into glacial refugium during glacial advances. Even today, these glacial refugium are considered genetic hot spots for Malus, and could be useful for future apple breeding. As the Pleistocene came to a close, many megafauna were going extinct. This continued into the Holocene. Large-fruited apple species lost their primary seed dispersers, and their ranges became even more contracted.

Humans have had an extensive relationship with apples, which began long before domestication. Foraging for apples was common, and seeds were certainly spread that way (perhaps even intentionally). Favorable growing conditions were also created when forests were cleared and old fields were left fallow. Apple trees are early successional species that easily colonize open landscapes, gaps in forests, and forest edges, so human activity that would have created such conditions “could have greatly promoted the spread and success of wild Malus spp. trees during the Holocene.”

The earliest evidence we have of apple domestication (in which “people were intentionally breeding and directing reproduction”) occurred around 3000 years ago in the Tian Shan Mountains of Kazakhstan, where Malus sieversii – a species that is now facing extinction – was being cultivated. This species was later brought into contact with other apple species, a few of which were also being cultivated, including M. orientalis, M. sylvestris, and M. baccata. These species easily hybridized, giving us the modern, domesticated apple, M. domestica. As Spengler writes, “the driving force of apple domestication appears to have been the trans-Eurasian crop exchange, or the movement of plants along the Silk Road.” Continued cultivation and further hybridization among M. domestica cultivars over the past 2000 years has resulted in thousands of different apple varieties.

The unique thing about domesticated apples is that their traits are not fixed in the same way that traits of other domesticated crops are. Growing an apple from seed will result in a very different apple than the apple from which the seed came. Apple traits instead have to be maintained through cloning, which is accomplished mainly through cuttings and grafting. Apples hybridize with other apple species so readily that most apple trees found in the wild are hybrids between wild and cultivated populations.

Spengler considers the study of apple domestication to be “an important critique of plant domestication studies broadly, illustrating that there is not a one-size fits-all model for plant domestication.” The “key” for understanding apple domestication “rests in figuring out the evolutionary driver for large fruits in the wild – seed dispersal through megafaunal mammals – and the process of evolution for these large fruits – hybridization.” He notes that “domestication studies often ignore evolutionary processes leading up to human cultivation,” which, in the case of apples, involves “hybridization events in the wild” that led to the evolution of large fruits “selected for through the success in recruiting large megafaunal mammals as seed disperses.” Many of those mammals went extinct, but humans eventually assumed the role, selecting and propagating “large-fruiting hybrids through cloning and grafting – creating our modern apple.”

Excerpt from Fruit from the Sands by Robert N. Spengler:

Indeed, the relationship between apples and people is close and complex, spanning at least five millennia. The story of the apple begins along the Silk Road… In recent years genetic studies have resolved much of the debate over these origins. Nevertheless, the ancestry of the apple is highly complex. Cloning, inbreeding, and reproduction between species have created a genealogy that looks more like a spider’s web than a family tree. To growers, the beauty of the apple lies not in its rosy skin but in its genetic variability and plasticity, its ability to cross with other species of Malus and other distant lines of M. domestica, and the ease with which it can be grafted onto different rootstocks and cloned.

See Also: Science Daily – Exploring the Origins of the Apple

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Interested in learning more about how plants get around? Check out the first issue of our new zine Dispersal Stories.

Winter Interest in the Lower Boise Foothills

The Boise Foothills, a hilly landscape largely dominated by shrubs and grasses, are a picturesque setting any time of the year. They are particularly beautiful in the spring when a wide array of spring flowering plants are in bloom, and then again in late summer and early fall when a smaller selection of plants flower. But even when there aren’t flowers to see, plants and other features in the Foothills continue to offer interest. Their beauty may be more subtle and not as immediately striking as certain flowers can be, but they catch the eye nonetheless. Appeal can be found in things like gnarled, dead sagebrush branches, lichen covered rocks, and fading seed heads. Because the lower Boise Foothills in particular have endured a long history of plant introductions, an abundance of weeds and invasive plants residing among the natives also provide interest.

This winter has been another mild one. I was hoping for more snow, less rain, and deeper freezes. Mild, wet conditions make exploring the Foothills difficult and ill-advised. Rather than frozen and/or snow covered, the trails are thick with mud. Walking on them in this state is too destructive. Avoiding trails and walking instead on trail side vegetation is even more destructive, and so Foothills hiking is put on hold until the ground freezes or the trails dry out. This means I haven’t gotten into the Foothills as much as I would like. Still, I managed to get a few photos of some of the interesting things the lower Boise Foothills have to offer during the winter. What follows is a selection of those photos.

snow melting on the fruit of an introduced rose (Rosa sp.)

fading seed heads of hoary tansyaster (Machaeranthera canescens)

samaras of box elder (Acer negundo)

snow on seed heads of yarrow (Achillea millefolium)

gall on introduced rose (Rosa sp.)

sunflower seed heads (Helianthus annuus)

sunflower seed head in the snow (Helianthus annuus)

snow falling in the lower Boise Foothills

fading seed heads of salsify (Tragopogon dubius)

lichen on dead box elder log

seed head of curlycup gumweed (Grindelia squarrosa)

lichen and moss on rock in the snow

fruits of poison ivy (Toxicodendron radicans)

See Also: Weeds and Wildflowers of the Boise Foothills (June 2015)

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The first issue of our new zine, Dispersal Stories, is available now. It’s an ode to traveling plants. You can find it in our Etsy Shop

Camel Crickets and the Dust Seeds of Parasitic Plants

A common way for plants to disperse their seeds is to entice animals to eat their seed-bearing fruits – a strategy known as endozoochory. Undigested seeds have the potential to travel long distances in the belly of an animal, and when they are finally deposited, a bit of fertilizer joins them. Discussions surrounding this method of seed dispersal usually have birds and mammals playing the starring roles – vertebrates, in other words. But what about invertebrates like insects? Do they have a role to play in transporting seeds within themselves?

Certain insects are absolutely important in the dispersal of seeds, particularly ants. But ants aren’t known to eat fruits and then poop out seeds. Instead they carry seeds to new locations, and some of these seeds go on to grow into new plants. In certain cases there is an elaisome attached to the seed, which is a nutritious treat that ants are particularly interested in eating. Elaisomes or arils have also been known to attract other insects like wasps and crickets, which may then become agents of seed dispersal. But endozoochory in insects, at first, seems unlikely. How would seeds survive not being crushed by an insect’s mandibles or otherwise destroyed in the digestion process?

camel crickets eating fruits of parasitic plants (via New Phytologist)

While observing parasitic plants in Japan, Kenji Suetsugu wanted to know how their seeds were dispersed. Many parasitic plants rely on wind dispersal, thus their seeds are minuscule, dust-like, and often winged. However, the seeds of the plants Suetsugu was observing, while tiny, were housed in fleshy fruits that don’t split open when ripe (i.e. indehiscent). This isn’t particularly unusual as other species of parasitic plants are known to have similar fruits, and Suetsugu was aware of studies that found rodents to be potential seed disperers for one species, birds to be dispersers of another, and even one instance of beetle endozoochory in a parasitic plant with fleshy, indehiscent fruit. With this in mind, he set out to identify the seed dispersers in his study.

Suetsugu observed three achlorophyllous, holoparisitic plants – Yoania amagiensis, Monotropastrum humile, and Phacellanthus tubiflorus. While their lifestyles are similar, they are not at all closely related and represent three different families (Orchidaceae,  Ericaceae, and Orobanchaceae respectively). All of these plants grow very low to the ground in deep shade below the canopy of trees. Air movement is at a minimum at their level, so seed dispersal by wind is not likely to be very effective. Using remote cameras, Suetsugu captured dozens of hours of footage and found camel crickets and ground beetles to be the main consumers of the fruits, with camel crickets being “the most voracious of the invertebrates.” This lead to the next question – did the feces of the fruit-eating camel crickets and ground beetles contain viable seeds?

Monotropastrum humile via wikimedia commons

After collecting a number of fecal pellets from the insects, Suetsugu determined that the seeds of all three species were “not robust enough to withstand mastication by the mandibles of the ground beetles.” On the other hand, the seeds passed through the camel crickets unscathed. A seed viability test confirmed that they were viable. Camel crickets were dispersing intact seeds of all three parasitic plants via their poop. The minuscule size of the seeds as well as their tough seed coat (compared to wind dispersed seeds of similar species) allowed for safe passage through the digestive system of this common ground insect.

In a later study, Suetsugu observed another mycoheterotrophic orchid, Yoania japonica, and also found camel crickets to be a common consumer of its fleshy, indehiscent fruits. Viable seeds were again found in the insect’s frass and were observed germinating in their natural habitat. Seutsugu noted that all of the fruits in his studies consumed by camel crickets are white or translucent, easily accessible to ground dwelling insects, and give off a fermented scent to which insects like camel crickets are known to be attracted. Camel crickets also spend their time foraging in areas suitable for the growth of these plants. All of this suggests co-evolutionary adaptations that have led to camel cricket-mediated seed dispersal.

Yoania japonica via wikimedia commons

Insect endozoochory may be an uncommon phenomenon, but perhaps it’s not as rare as we once presumed. As mentioned above, an instance of endozoochory by a beetle has been reported, as has one by a species of cockroach. Certainly the most well known example involves the wetas of New Zealand, which are large, flightless insects in the same order as grasshoppers and crickets and sometimes referred to as “invertebrate mice.” New Zealand lacks native ground-dwelling mammals, and wetas appear to have taken on the seed dispersal role that such mammals often play.

Where seeds are small enough and seed coats tough enough, insects have the potential to be agents of seed dispersal via ingestion. Further investigation will reveal additional instances where this is the case. Of course, effective seed dispersal means seeds must ultimately find themselves in locations suitable for germination in numbers that maintain healthy populations, which for the dust seeds of parasitic plants is quite specific since they require a host organism to root into. Thus, effective seed dispersal in these scenarios is also worth a more detailed look.

Further Reading:

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For more stories of seed dispersal check out the first issue of my new zine, Dispersal Stories.

Seed Dispersal by Way of Tree Climbing Goats

Goats are surprisingly good climbers. Given the opportunity, they’ll climb just about anything, including each other. So what’s stopping them from climbing a tree, especially if there is something up there they can eat? And so they do. Tree climbing goats are such a fascinating sight, they even have their own calendar. But the story doesn’t end there. The goats find food in the trees, entertaining humans as they go; meanwhile, the trees have a reliable partner in the goats, who inadvertently help disperse the tree’s seeds.

In general, goats don’t need to climb trees to find food. Goats aren’t known to be picky eaters, and there is usually plenty for them to eat at ground level. However, in arid climates where food can become limited, ascending trees to eat foliage and fruits is a matter of survival. This is the case in southwestern Morocco, where goats can be found in the tops of argan trees every autumn gorging on the fruits of this desert tree.

goats in Argania spinosa via wikimedia commons

Argan (Argania spinosa) is a relatively short tree with a sprawling canopy and thorny branches. It is the only species in its genus and is endemic to parts of Morocco and neighboring Algeria. The tree is economically important to the area due to the oil-rich seeds found within its bitter fruits. Argan oil has a variety of culinary uses and is also used medicinally and in cosmetics. To get to the oil, goats are often employed in harvesting the fruits. The goats retrieve the fruits from the tops of the trees and consume their fleshy outer layer. The hard, seed-containing pits are expelled, collected, and cracked open to get to the seeds.

This is where a team of researchers from Europe come in. There has been some confusion as to how the pits are expelled, with some reports claiming that they pass through the goats digestive track and are deposited in their manure. This is a common way for the seeds of many other plant species to be dispersed, and is carried out not only by goats and other ruminants, but also by a wide variety of mammals, as well as birds and even reptiles. However, considering the average size of the pits (22 mm long x 15 mm wide), the researchers thought this to be unlikely.

fruits of Argania spinosa via wikimedia commons

Others reported that the seeds were spat out in the goats’ cud while they ruminated. Goats, like other ruminants, have stomachs composed of multiple compartments, the first of which being the rumen. Partially digested food, known as cud, is sent back into the mouth from the rumen for further chewing and may be spat out or swallowed again. Goats are known to ruminate in the same location that they defecate, which results in confusion as to when and how certain seeds, like those of the argan tree, are deposited.

By feeding various fruits to a group of goats, the researchers were able to test the hypothesis that seeds could be regurgitated and spat from the cud and that this is a viable method of seed dispersal. The researchers reported that larger seeds were more commonly spat out than smaller seeds, but that “almost any seed could be ejected during, mastication, spat from the cud, digested, or defecated.” The viability of spat out seeds was tested, and over 70% of them were found to be viable.

pits and seeds of Argania spinosa via wikimedia commons

This discovery suggests that seed dispersal via spitting by ruminants could be a common occurrence – possibly far more common than previously considered. The researchers postulate that studies that have only considered seeds dispersed in manure “may have underestimated an important fraction of the total number of dispersed seeds” and that the seeds spat from the cud likely represent different species from those commonly dispersed in dung. In addition, the seeds of some species don’t survive the digestive tract of ruminants, so “spitting from the cud may represent their only, or at least their main, dispersal mechanism.”

This study surrounding the argan trees was followed up by the same group of researchers with a literature review that was published last month. The review looked into all available studies that mentioned seed dispersal via regurgitation by ruminants. While they considered over 1000 papers, only 40 published studies were found to be relevant for the review. From these studies, they determined that the seeds of 48 plant species (representing 21 different families) are dispersed by being spat from a ruminant’s cud, and that most of these plant species are trees and shrubs whose fruits contain large seeds. Also of note is that ruminants across the globe are doing this – representatives from 18 different genera were mentioned in the studies.

ruminating goat via wikimedia commons

The researchers conclude that this is a “neglected” mechanism of seed dispersal. It’s difficult to observe, and in many cases it hasn’t even been considered. Like so many other animals, ruminants can disperse seeds in a variety of ways. Seeds can attach to their fur and be transported wherever they go. They can pass through their digestive track and end up in their dung, potentially far from where they were first consumed. And, as presented here, they can be spat out during rumination. Investigations involving all of these mechanisms and the different plant species involved will allow us to see, in a much clearer way, the role that ruminants play in the dispersal of seeds.

Tiny Plants: Idahoa

This is a post I wrote three years ago as a guest writer for a blog called Closet Botanist. That blog has since dissolved, hence the re-post.

This year, we returned to the location in the Boise Foothills where I encountered the plant that inspired this post. I found what might be seedlings of the tiny plant. If that’s the case, the phenology is a bit delayed compared to three years ago. I’ll check again in a week or so. Until then, meet Idahoa.

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I have taken a real liking to tiny plants. So many of the plants we regularly interact with are relatively big. Large trees loom above us. Tall shrubs greet us at eye level. Flowering perennials come up around our knees or higher. But how often do we get down low and observe the plants that hug the ground or that reach just a few centimeters above it? Turf grass is ubiquitous and groundcovers are common, but among such low growing plants (or plants kept low), even more diminutive species lurk.

It was a hunt for a tiny plant that sent me down a certain trail in the Boise Foothills earlier this spring. Listening to a talk by a local botanist at an Idaho Native Plant Society meeting, I learned about Idahoa scapigera. A genus named after Idaho!? I was immediately intrigued. Polecat Gulch was the place to see it, so off I went.

Commonly known as oldstem idahoa, flatpod, or Scapose scalepod, Idahoa scapigera is the only species in its genus. It is an annual plant in the mustard family, which means it is related to other small, annual mustard species like Draba verna. It is native to far western North America and is distributed from British Columbia down to California and east into Montana. It occurs in a variety of habitat types found in meadows, mountains, and foothills.

Idahoa scapigera is truly tiny. Before it flowers, it forms a basal rosette of leaves that max out at about 3 centimeters long. Next it sends up several skinny flower stalks that reach maybe 10 centimeters high (some are much shorter). One single flower is born atop each stalk. Its petite petals are white and are cupped by red to purple sepals. Its fruit is a flat round or oblong disk held vertically as though it is ready to give neighboring fruits a high five. Happening upon a patch of these plants in fruit is a real joy.

Which brings me to my hunt. It was the morning of March 20th (the first day of Spring) when I headed down the Polecat Gulch trail in search of Idahoa, among other things. The trail forms a loop around the gulch and is about 6 miles long with options for shortening the loop by taking trails that cut through the middle. I have yet to make it all the way around. Stopping every 10 yards to look at plants, insects, and other things makes for slow hiking.

I was about a half mile – 1 hour or more – into the hike when Idahoa entered my view. A group of them were growing on the upslope side of the trail, greeting me just below waist level. Many of them had already finished flowering and had fresh green fruits topping their thin stalks. At this location they are a late winter/early spring ephemeral. I made a mental note of the site and decided to return when the fruits had matured. Next year, I will head out earlier in hopes of catching more of them in flower.

On the way to Idahoa, I noted numerous other small, green things growing in the sandy soil. It turns out there are countless other tiny plants to see and explore. It got me thinking about all the small things that go unnoticed right underneath our feet or outside of our view. I resolved to move slower and get down lower to observe the wonders I’ve been overlooking all this time.

Further Reading:

Inside of a Seed: Two Monocots

“Seeds are travelers in space and time – small packages of DNA, protein, and starch that can move over long distances and remain viable for hundreds of years. These packages have everything they need not only to survive, but also to grow into a plant when they encounter the right conditions.”      The Book of Seeds by Paul Smith

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As illustrated in last week’s post, the mature seeds of dicots – depending on the species – can be either with or without endosperm (a starchy food packet that feeds a growing seedling upon germination). Seeds without endosperm store these essential sugars in their cotyledons. Monocotyledons (or monocots, for short) are a group of flowering plants (i.e. angiosperms) whose seedlings are composed of a single cotyledon. With the exception of orchids, the seeds of monocots always contain endosperm.

The first of two examples of monocot seeds is the common onion (Allium cepa). The embryo in this seed sits curled up, surrounded by endosperm inside of a durable seed coat.

If you have ever sown onion seeds, you have watched as the single, grass-like cotyledon emerges from the soil. The seed coat often remains attached to the tip of the cotyledon like a little helmet as it stretches out towards the sky. Soon the first true leaf appears, pushing out from the base of the cotyledon. The source of this first leaf is the plumule hidden within the cotyledon.

The fruit of plants in the grass family – including cereal grains like wheat, oats, barley, rice, and corn – is called a caryopsis. In this type of fruit, the fruit wall (or pericarp) is fused to the seed coat, making the fruit indistinguishable from the seed. The embryos in these seeds are highly developed, with a few more discernible parts. A simplified diagram of a corn seed (Zea mays) is shown below. Each kernel of corn on a cob is a caryopsis. These relatively large seeds are great for demonstrating the anatomy of seeds in the grass family.

In these seeds there is an additional layer of endosperm called aleurone, which is rich in protein and composed of living cells. The cells of the adjacent endosperm are not alive and are composed of starch. The embryo consists of several parts, including the cotyledon (which, in the grass family, is also called a scuttelum), coleoptile, plumule, radicle, and coleorhiza. The coleoptile is a sheath that protects the emerging shoot as it pushes up through the soil. The plumule is the growing point for the first shoots and leaves, and the radicle is the beginning of the root system. The emerging root is protected by a root cap called a calyptra and a sheath called a coleorhiza.

Germination begins with the coleorhiza pushing through the pericarp. It is quickly followed by the radicle growing through the coleorhiza. As the embryo emerges, a signal is sent to the endosperm to start feeding the growing baby corn plant, giving it a head start until it can make its own food via photosynthesis.

corn seeds (Zea mays)

Up Next: We’ll take an inside look at the seeds of gymnosperms.

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Field Trip: Bergius Botanic Garden and Copenhagen Botanical Garden

There are very few downsides to working at a botanical garden, but one of them is that the growing season can be so busy that taking time off to visit other botanical gardens when they are at their peak is challenging. Case in point, my visit to Alaska Botanical Garden last October. Another case in point, this December’s visit to a couple of gardens in Scandinavia.

That’s right, Sierra and I took a long (and much needed) break from work and headed to the other side of the world for some fun in the occasional sun of Denmark and Sweden. While we were there we visited two botanical gardens, one in Stockholm and the other in Copenhagen. Considering we were there in December, we were impressed by how many things we found all around that were still blooming. We were also impressed by how much winter interest there was in the form of seed heads, spent flower stalks, and other plant parts left in place, as opposed to everything being chopped down to the ground as soon as fall arrives (which is often the case in our part of the world). We may not have been there in the warmest or sunniest time of year, but there was still plenty of natural beauty to capture our attention.

Bergius Botanic Garden

The first of the two gardens we visited was Bergius Botanic Garden (a.k.a. Bergianska trädgården) in Stockholm, Sweden. It is located near Stockholm University and the Swedish Museum of Natural History. It was founded in 1791 and moved to its current location in 1885. It was immediately obvious that the gardens were thoughtfully planned out, particularly the systematic beds in which the plants were organized according to their evolutionary relationship to each other. The extensive rock garden, which was a collection of small “mountains” with a series of paths winding throughout, was also impressive. Since we arrived just as the sun was beginning to set, we were happy to find that the Edvard Anderson Conservatory was open where we could explore a whole other world of plants, many more of which were flowering at the time.

Walking into Bergius Botanic Garden with the Edvard Anderson Conservatory in the distance.

Sierra poses with kale, collard, and Brussels sprout trees in the Vegetable Garden.

seed heads of velvetleaf (Abutilon theophrasti)

corky bark of cork-barked elm (Ulmus minor ‘Suberosa’)

pomelo (Citrus maxima) in the Edvard Anderson Conservatory

Camellia japonica ‘Roger Hall’ in the Edvard Anderson Conservatory

carrion-flower (Orbea variegata) in the Edvard Anderson Conservatory

Cape African-queen (Anisodontea capensis) in the Edvard Anderson Conservatory

Copenhgen Botanical Garden

The Copenhagen Botanical Garden (a.k.a. Botanisk have) is a 10 hectare garden that was founded in 1600 and moved to its current location in 1870. It is part of the University of Copenhagen and is located among a series of glasshouses built in 1874, a natural history museum, and a geological museum. Unfortunately, the glasshouses and museums were closed the day we visited, but we still enjoyed walking through the grounds and exploring the various gardens.

A large rock garden, similar to the one at Bergius, was a prominent feature. We learned from talking to a gardener working there that since Denmark is not known for its rich supply of large rocks, most of the rocks in the garden came from Norway. However, a section of the rock garden was built using fossilized coral found in Denmark that dates back to the time that the region was underwater.

Another great feature was the Nordic Beer Garden, a meticulously organized collection of plants used in beer recipes from the time of the Vikings to the Nordic brewers of today. Even though the majority of the plants in this garden were dormant, the interpretive signage and fastidious layout was memorable.

Walking into Copenhagen Botanical Garden with the Palm House in the distance.

lots of little pots of dormant bulbs

seed head of Chinese licorice (Glycyrrhiza echinata)

fruits of Chinese lantern (Physalis alkekengi)

alpine rose (Rhododendron ferrugineum)

Viburnum farreri ‘Nanum’

seed head of rose of Sharon (Hibiscus syriacus)

pods exposing the seeds of stinking iris (Iris foetidissima)

Field Trip: UBC Botanical Garden and VanDusen Botanical Garden

Last week, we found ourselves in Vancouver, British Columbia for a work-related conference put on by American Public Gardens Association. In addition to learning heaps about plant collections and (among other things) the record keeping involved in maintaining such collections, we got a chance to visit two Vancouver botanical gardens. Both gardens were pretty big, so covering the entire area in the pace we generally like to go in the time that was allotted was simply not possible. Still, we were smitten by what we were able to see and would happily return given the chance. What follows are a few photos from each of the gardens.

UBC Botanical Garden

UBC Botanical Garden is located at the University of British Columbia. Established in 1916, it is Canada’s oldest university botanical garden. We saw a small fraction of the Asian Garden, which is expansive, and instead spent most of our time in other areas, including the Alpine Garden, the Carolinian Forest Garden, the Food Garden, and one of my favorite spots, the BC Rainforest Garden. The Rainforest Garden is a collection of plants native to British Columbia, which was the original focus of UBC Botanical Garden’s first director, John Davidson.

fall foliage of redvein enkianthus (Enkianthus campanulatus)

Franklin tree in bloom (Franklinia alatamaha) in the Carolinian Forest Garden

alpine troughs

bellflower smartweed (Aconogonon campanulatum)

cutleaf smooth sumac (Rhus glabra ‘Laciniata’) in the BC Rainforest Garden

the fruits of Gaultheria pumila in the E.H. Lohbrunner Alpine Garden

Himalayan blueberry (Vaccinium moupinense) in the E.H. Lohbrunner Alpine Garden

VanDusen Botanical Garden

VanDusen Botanical Garden is a 55 acre garden that opened in 1975 and is located on land that was once a golf course. It features an extensive collection of plants from around the world accompanied by a series of lakes and ponds as well as lots of other interesting features (like a Scottish Shelter, a Korean Pavilion, an Elizabethan Maze, and more). Our time there was far too brief. The whirlwind tour we joined, led by the education director, was a lot of fun, and if the threat of missing our bus wasn’t looming, we would have been happy to stay much longer.

Japanese anemone (Anemone x hybrida ‘Whirlwind’)

fall color on the shore of Heron Lake

knees of bald cypress (Taxodium distichum) in R. Roy Forster Cypress Pond

witch hazel (Hamamelis x intermedia ‘Pallida’)

a grove of giant redwoods (Sequoiadendron giganteum)

We tried the fruit of dead man’s fingers (Decaisnea insignis). It tastes a bit like watermelon.

Japanese stewartia (Stewartia pseudocamellia)

More Awkward Botany Field Trips: