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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Inside of a Seed: Two Dicots

“A seed is a living thing that embodies roots, stems, leaves, and fruit in an embryonic state and retains the ability to convert the sun’s energy into a source of food.” — Seedtime by Scott Chaskey

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Few things are more miraculous than seeds. Within them is a living plant in embryonic form. Under the right conditions, these tiny objects expand, pushing out the beginnings of the most minuscule weed to the most humongous tree. Looking at these otherwise unassuming specks, you would hardly guess that they held such potential.

Housed in a seed is the genetic material necessary for growth and reproduction, along with some stored sugars to get the plant started. All of this is enclosed in a protective case. It is a rare moment in a plant’s life – a time when it isn’t rooted in place and can, for a brief period, move around. With the help of agents like wind, water, and animals it can travel anywhere in the world, venturing as far as inches or miles from its parent plant. As long as it finds a suitable place to grow, its voyage is not in vein.

Seeds are the result of sexual reproduction in plants (with rare exceptions, which we will cover in a future post). After pollination, a pollen grain sends three haploid cells into the ovule of a flower. These cells unite with the haploid cells found within. One germ cell from the pollen grain goes to the formation of an embryo, while the other two cells help form endosperm, the food source for the developing embryo. The wall of the ovule becomes the outer layer of the seed, known as the seed coat or testa. The seed matures as the fruit it is nested in ripens. Eventually, the fetal plant within the seed is ready to find a new home.

Seed heads of rubber rabbitbrush (Ericameria nauseosa) – the fuzzy pappus attached to the fruits allows seeds to float in the breeze and travel away from their parent plant.

As with so many things in biology, there is no single type of seed. When it comes to seed anatomy, most seeds consist of the same basic components, but each species of plant has its own unique seed. In fact, a well-trained taxonomist can identify plants simply by observing their seeds. With such a wide variety of seeds, it is difficult to organize them into discrete categories, but we still try. What follows is an introduction to two types of seeds – endospermic and non-endospermic – using two basic examples.

The first thing you should know about these two examples is that both species are dicotyledons (or dicots, for short). This means that when the baby plant emerges, it has two cotyledons, which are also called embryonic leaves because they look like little leaves. All flowering plants have been divided into two groups based on the number of cotyledons they have, the second group being the monocotolydons (or monocots) which have only one cotyledon. This is an old-fashioned way to classify plants, but it is still useful in some instances.

Endospermic Seeds

The seeds of the castor bean plant (Ricinus communis) are endospermic seeds. This means that they retain the endosperm that was formed when two pollen grain cells joined up with the haploid cell in the ovule. The endosperm will help feed the growing embryo as it germinates. The two cotyledons are visible within the seed, but they are thin and broad, leaving plenty of space in the seed for the endosperm. The cotyledons are part of the embryo and are attached to the radicle, which is the embryonic root. The radicle is the first thing to emerge from the seed upon germination. The area between the radicle and the cotyledon is known as the hypocotyl. It becomes the stem of the germinating seedling.

An elaisome is attached to the outside of the seed coat of castor bean seeds. This fleshy, nutrient-rich appendage is particularly attractive to ants. They carry the seeds back to their colony and feed the elaisome to their young. The seeds, however, remain unconsumed. In this way, the ants aid in the seeds’ dispersal.

seeds of castor beans (Ricinus communis)

Non-endospermic Seeds

The seeds of plants in the bean family (Fabaceae) are non-endospermic seeds. This means that as the embryo develops, it uses up the majority of the endosperm within the seed. The food necessary for the seedling to get its start is all stored in its cotyledons. The common pea (Pisum sativum) is a good example of this. The embryo – which consists of the cotyledons, plumula (or plumule), hypocotyl, and radicle – takes up all available space inside of the seed coat. After germination, as the seedling develops, the plumule appears above the cotyledons and is the growing point for the first true leaves and stems.

seeds of the common pea (Pisum sativum)

In future posts, we will look at a few other types of seeds, as well as discuss various other seed-related topics. If you have a story to share about seeds, please do so in the comment section below.

2018: Year in Review

Another year has passed, which means it’s time again for a Year in Review. As I have done in the past, I am including links to a selection of posts that came out in 2018. Most of these posts are part of ongoing series. You can find the rest of the posts from 2018 in the Archives widget on the right side of the screen (or at the bottom of the page if you are viewing this on a mobile device).

Among many memorable happenings this year, the one I feel most compelled to highlight here is a short radio show that a friend and I started doing on Radio Boise, our community radio station. The show is called Boise Biophila, and each week Casey O’Leary and I spend about a minute each talking about something biology or ecology related with the goal of encouraging people to get outside and take a closer look at the natural world around them. After the shows air, I put them up on our Soundcloud page for all to hear for years to come. You can follow us there, as well as on our Facebook page.

Ficus carica via PhyloPic

In the spring of 2018 we set up a Donorbox account, which is a simple way for people who enjoy Awkward Botany and want to see it continue to give us a little financial encouragement. We received several donations at that time, and we are very grateful to those that contributed. But just like public radio or any other organization that would like to receive your support in the form of money, we continue our plea. If Awkward Botany means something to you and you feel compelled to share some of your hard-earned dollars with us, we are happy to receive them and promise to put them to good use.

Donate

Money aside, a major contribution you can make to the success of Awkward Botany is to share it with your friends. Spread the word in conversation, through the postal system, over the phone, or through one or more of the myriad social media platforms. However you choose to share is none of our business. We are just happy that you do.

You are also encouraged to follow our various social media pages: Twitter, Tumblr, and Facebook. Above all, keep reading. We have lots more posts in the works for 2019, and we wouldn’t want you to miss out on the fun. Our appreciation for plants and the natural world is a constant, and we hope you will continue to share in our botany nerd revelry throughout the coming year.

Fragaria vesca via PhyloPic

Book Reviews:

Botany in Popular Culture:

Tiny Plants:

Field Trip:

Eating Weeds:

Two-parters:

Guest Posts:

The Dragon of Yankee Fork: Grave Markers

This is a guest post by Martha Dalke Hindman. It is an excerpt from her upcoming book, The Dragon of Yankee Fork. This is the second of three posts. See also: Devil’s Washbasins.

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Grave Markers preserve for the Ages, records etched in stone.
The Firefighters Circle, Woodlawn Cemetery, St. Maries, Idaho.
57 of the 94 men, who perished fighting the Great Fire of 1910
Rest together in this Sacred Space.

Sentinels towering in the late afternoon Sun,
Old growth Western Red Cedar trees,
Their fragrant, graceful boughs swaying in the breeze
Watch over the square, Red Granite stones.

western redcedar (Thuja plicata)

On a warm and breezy Wednesday afternoon in 2005, peaceful and quiet when Kaye and I visited Woodlawn Cemetery in St. Maries, Idaho. The Firefighters Circle, a tribute to the men who died fighting the Great Fire of 1910. Here, together they rest forever.

“Look carefully at the Grave Markers, Kaye.”

“Do you see the names of each firefighter and the place where he perished; Big Creek, Storm Creek, Defaut Gulch, Swamp Creek and Wallace?”

The men were buried where they had fallen. In 1912, the United States Forest Service hired an undertaking company to exhume the bodies and bring them here to Woodlawn Cemetery, to be identified by family members. The bodies identified by family members are buried in several cities in Idaho and five other states beyond Idaho’s borders. The firefighters with no family members to identify them were first generation immigrant men from Europe. Those are the fifty-seven men buried in a “circle within a circle”, facing each other, creating their own “family” here in Woodlawn Cemetery.

Firefighters’ Circle at Woodlawn Cemetery, St. Maries, Idaho in 2005

My daughter stopped for a moment, tears in her eyes. Her gaze met mine.

“Why the tears, Sweetie?” I asked.

I realized from her expression she was remembering her father’s graveside service in May, 1994. I put my arms around her and held her close. She was missing her Dad, just as much as the families of those firefighters resting together at Woodlawn Cemetery, were missing their loved ones.

The Firefighters Circle at Woodlawn Cemetery, St. Maries, Idaho was rededicated, August 20, 2010, with parades, speeches and an ongoing commitment by the men and women who help protect Idaho’s natural woodlands.

Firefighters’ Circle at Woodlawn Cemetery, St. Maries, Idaho in 2015 (via wikimedia commons)

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Poetry, personal stories, images, journal entries, recipes for Springerle, Cinnamon Rolls, Fried Cakes, “a little bit of science thrown in for good measure,” print and online resources, all define “The Dragon of Yankee Fork,” an Idaho Alphabet from A to Z. It all began on a long piece of cream colored shelf paper! (Visit the Go Fund Me page to learn more about the project and contribute to its creation.)

Martha Dalke Hindman’s outdoor classroom was the travel adventures she shared with her father around the State of Idaho. From dusty roads, fishing expeditions, and a keen sense of observation, learning about Idaho’s heritage gave Ms. Hindman her voice in poetry and personal short stories. She may be reached at martha20022 [at] gmail [dot] com.

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)

Book Review: What Weeds Are Thinking

Plant intelligence is a burgeoning field of research. Despite being predominantly sessile organisms, plants are able to sense their surroundings and make decisions based on environmental cues. In a certain sense, they can see, hear, smell, and remember even though they don’t have eyes, ears, noses, or brains. Not surprisingly, these fascinating findings have spawned books, podcasts, documentariesarticles, etc. The idea that plants could be intelligent beings like us is something that captures our attention and imagination.

For example, if plants are so smart, does this mean that they actually have thoughts? And if they have thoughts, what could they possibly be thinking? In her new book, What Weeds Are ThinkingErica Crockett takes a stab at what a particularly despised group of plants might think if, indeed, they could have thoughts. Weeds are, in Crockett’s words, “the deviants of the plant world.” This book was her chance to imagine what might be going on inside the minds of these deviants, despite the fact that they don’t have minds.Crockett conjures up the thoughts of 21 different weeds. Each thought is accompanied by an illustration by Sarah Ragan Olson. The drawings are charming, but the thoughts that juxtapose them aren’t always so sweet. Perhaps you imagine weeds to be potty mouthed? Well, so does Crockett. That being said, this book is not for kids, nor is it for anyone sensitive to adult words and themes. Each of the weeds in this book varies in its degree of irreverence – not all of them are so crass and some of them are actually pretty mild-mannered – but that’s just what you’d expect from such a diverse group of plants.

Comfrey is offended by cow manure being used as fertilizer and would rather be fertilized by “the decaying corpses of [its] relations.” Ground ivy is embarrassed and offended by inadvertently seeing the ankles of human passersby.  Plantain is apparently into being stepped on, and prostrate spurge is trying to “rebrand” to make itself more appealing and set itself apart from purslane. Cheatgrass, no surprise here, comes across as a big jerk. Originally from Eurasia, it is now a freedom-loving American, “choking out the rights of the natives.”

Most in line with what I would expect a weed to be thinking – especially one found growing in an urban area – is prickly lettuce. Upset after watching a fellow member of its species ruthlessly dug up, it laments: “Neither of us decided to seed down in the deep crack of this suburban driveway. We were blown here…It’s our home…Yet we are hunted.”

Milkweed is quite aware of its role as the sole food source of the monarch caterpillar. It sees how much humans appreciate monarchs, and admonishes us for killing off its kind: “Keep it up, and I’ll take every last one of those delicate darlings down with me.”

Botanical inaccuracies aside – and there are several – this was a fun book. The main appeal for me is that it is plant-themed and, more specifically, weeds-themed. If you follow this blog, you’ll know that pretty much anything involving weeds is going to get my attention. Beyond that, any project that puts plants in the spotlight and gives them a voice (even in a fictitious sense) is worth checking out. This book is no exception.

As a bonus, I asked Erica Crockett what other plants (apart from weeds) are thinking. This was her response: “Probably really precious or intellectual things. I imagine tomato plants are fairly self-important and zonal geraniums are divas. Bougainvilleas are likely social climbers and oak trees are dull, but honest.”

More Weeds-themed Book Reviews on Awkward Botany:

More Urban Botanical Art

Two years ago I shared my first collection of urban botanical art photos. Since that time I have collected several more. I had hoped to get lots of photos during my trips out of town, and while I did manage to get a few, it turns out that my hometown of Boise, Idaho has a sizable (and growing) selection of plant-related public art. Thus, several of these are local finds.

As I mentioned in the original post, if you have photos of urban botanical art that you would like to share with me, please do so either through twitter, tumblr, facebook, or some other means.

Utility box on the corner of 13th and River Streets in Boise, Idaho

Utility box on American Legion Boulevard in Mountain Home, Idaho

Downtown Anchorage, Alaska

Downtown Anchorage, Alaska

Restrooms at the edge of Warm Springs Golf Course in Boise, Idaho. All plants represented are native to Idaho.

A plaque featuring botanical and common names accompanies each plant. 

Sculpture at Richmond Nature Park in Richmond, BC, Canada

In the Food Garden at UBC Botanical Garden in Vancouver, BC, Canada

Reverse-Rebirth sculpture by Han Seok Hyun at Idaho Botanical Garden in Boise, Idaho

Paintings of flowers displayed outside of Boise Creative Center in Boise, Idaho

Utility box on the corner of Myrtle Street and Broadway Avenue in Boise, Idaho

Downtown Mountain Home, Idaho (Community Canvas of Moho)

Mural by Stephen Murphy (my dad!) in downtown Mountain Home, Idaho (Community Canvas of Moho)