Selections from the Boise Biophilia Archives

For a little over a year now, I’ve been doing a tiny radio show with a friend of mine named Casey O’leary. The show is called Boise Biophilia and airs weekly on Radio Boise. On the show we each take about a minute to talk about something biology or ecology related that listeners in our local area can relate to. Our goal is to encourage listeners to get outside and explore the natural world. It’s fascinating after all! After the shows air, I post them on our website and Soundcloud page for all to hear.

We are not professional broadcasters by any means. Heck, I’m not a huge fan of talking in general, much less when a microphone is involved and a recording is being made. But Casey and I both love spreading the word about nerdy nature topics, and Casey’s enthusiasm for the project helps keep me involved. We’ve recorded nearly 70 episodes so far and are thrilled to know that they are out there in the world for people to experience. What follows is a sampling of some of the episodes we have recorded over the last 16 months. Some of our topics and comments are inside baseball for people living in the Treasure Valley, but there’s plenty there for outsiders to enjoy as well.

Something you will surely note upon your first listen is the scattering of interesting sound effects and off the wall edits in each of the episodes. Those come thanks to Speedy of Radio Boise who helps us edit our show. Without Speedy, the show wouldn’t be nearly as fun to listen to, so we are grateful for the work he does.

Boise Biophilia logo designed by Sierra Laverty

In this episode, Casey and I explore the world of leaf litter. Where do all the leaves go after they fall? Who are the players involved in decomposition, and what are they up to out there?

 

In this episode, Casey gets into our region’s complicated system of water rights, while I dive into something equally complex and intense – life inside of a sagebrush gall.

 

In this episode, I talk about dead bees and other insects trapped and dangling from milkweed flowers, and Casey discusses goatheads (a.k.a. puncture vine or Tribulus terrestris) in honor of Boise’s nascent summer celebration, Goathead Fest.

 

As much as I love plants, I have to admit that some of our best episodes are insect themed. Their lives are so dramatic, and this episode illustrates that.

 

The insect drama continues in this episode in which I describe how ant lions capture and consume their prey. Since we recorded this around Halloween, Casey offers a particularly spooky bit about garlic.

 

If you follow Awkward Botany, you know that one of my favorite topics is weeds. In this episode, I cover tumbleweeds, an iconic western weed that has been known to do some real damage. Casey introduces us to Canada geese, which are similar to weeds in their, at times, overabundance and ability to spawn strong opinions in the people they share space with.

 

In this episode, I explain the phenomenon of marcescence, and Casey gives some great advice about growing onions from seed.

 

And finally, in the spring you can’t get by without talking about bulbs at some point. This episode is an introduction to geophytes. Casey breaks down the basics, while I list some specific geophytes native to our Boise Foothills.

 

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Field Trip: Orton Botanical Garden

In the inaugural year of this blog, I wrote a short post about a visit to Plantasia Cactus Gardens, a botanical garden in Twin Falls, Idaho that specializes in cold hardy cactus and other succulents. I finally made a return visit all these years later (thanks to a co-worker who organized the trip). Back in 2013, the garden was private but open to the public by appointment. Today, the garden is still open by appointment but is now a 501(c)(3) non-profit organization with a new name: Orton Botanical Garden.

With the name change and non-profit status comes a new mission statement. The garden has been an impressive display of cold hardy cactus and succulents along with native and drought-tolerant plants for many years now. It has also long been a resource for educating visitors on the importance of these plants, as well as the importance of water conservation through water efficient landscaping. So the mission statement isn’t necessarily a new direction, but rather an affirmation of what this garden has done so well for years. Few gardens are doing cold hardy, drought-tolerant plants at the level that Orton Botanical Garden is.

Many of the plants at Orton Botanical Garden are made available to the public for purchase through an annual plant sale in May, as well as through an online store. This is another great service because sourcing some of these plants is not easy, and this one of the few places they can be found for sale.

Wherever you live in the world, this is a garden that should be on your bucket list. Even at a mere 5 acres in size, one could easily spend hours exploring it, and each visit reveals something new. What follows is just a small sampling of the things you will find there.

Toroweap hedgehog (Echinocereus coccineus var. toroweapensis)

scarlet hedgehog (Echinocereus coccineus var. coccineus)

White Sands kingcup cactus (Echinocereus triglochidiatus var. triglochidiatus)

Orcutt’s foxtail cactus (Escobaria orcuttii var. koenigii)

a peak down a shallow gully flanked by cholla (Cylindropuntia spp.)

Colorado hookless cactus (Sclerocactus glaucus)

Fremont’s mahonia (Mahonia fremontii)

close up of Fremont’s mahonia (Mahonia fremontii)

spiny pillow (Ptilotrichum spinosum)

hairstreak on cliff fendlerbush (Fendlera rupicola)

Utah sweetvetch (Hedysarum boreale)

Several species of buckwheats were in bloom, including this Railroad Canyon buckwheat (Eriogonum soliceps).

There were also quite a few penstemon species blooming, like this sidebells penstemon (Penstemon secundiflorus).

More Awkward Botany Field Trips:

Drought Tolerant Plants: Ice Plants

Among the various strategies plants have for tolerating drought, succulence is easily one of the most common and most successful. A recent article in the new open source journal, Plants People Planet, explores the world of succulent plants, commenting on, among other things, their evolution and extent. At least 83 plant families contain succulent species, and as many as 3-5% of flowering plants are considered succulents.

Succulence involves the storage of water in the cells of one or more plant organs (i.e. roots, stems, or leaves) as a mechanism for surviving drought. One way that succulent species differ is the location and nature of this storage. Some succulents are all cell succulents, meaning that the cells involved in storing water are also involved in carrying out photosynthesis. Other succulents are storage succulents. They have specific cells called hydrenchyma designed for storing water. These cells are non-photosynthetic.

Plants in the family Aizoaceae are storage succulents. Commonly known as the ice plant or carpet weed family, this family consists of hundreds of species and is mainly distributed throughout a region of South Africa known as Succulent Karoo. Species in this family earn the name ice plant thanks to numerous bladder-like cells or hairs that cover their leaves and stems causing them to sparkle or glimmer in the light. Aizoaceae diversity is incredible, and while this post focuses mainly on a few select species, it’s worth browsing through the profiles listed on World of Succulents to appreciate the breadth of forms these plants can take.

common ice plant (Mesembryanthemum crystallinum)

Among many interesting features that plants in this family possess, one particularly fun thing to note is that their flowers, which are unapologetically showy, lack true petals. Instead, what appear as a series of flat, thin petals encircling the center of the flower are actually modified stamens. They act as petals – drawing in pollinators with their bright colors – so calling them petals is acceptable, just not entirely accurate. Another fun fact is that seed pods of plants in Aizoaceae are often hygrochastic – upon getting wet they burst open and expel their seeds.

The photosynthetic pathway in succulents is generally different compared to other plants. Instead of the common C3 pathway, succulents use a pathway called CAM, or Crassulacean Acid Metabolism. CAM photosynthesis is similar to C4 photosynthesis – another photosynthetic pathway common among drought tolerant plants – in that it uses PEP carboxylase instead of rubisco to fix carbon and then sends it to a separate cell to be converted into sugars. In C4 photosynthesis, this whole process happens during the day. CAM photosynthesis differs in that it fixes carbon during the night and then sends it to another cell to be converted into sugars during the day. Fixing carbon at night is a way to avoid the water loss that occurs when collecting carbon dioxide during the daytime.

In discussing Aizoaceae, this is an important consideration because, unlike many other succulents, plants in this family don’t rely solely on CAM photosynthesis, but can instead switch back and forth between C3 and CAM. The ability to do this is likely because they are storage succulents rather than all cell succulents, and because they can do this, they are very efficient carbon fixers.

flowers fading on purple ice plant (Delosperma cooperi)

I live in a region where winter temperatures can dip into the single digits (°F) and sometimes lower,  so my familiarity with ice plants is with cold hardy species and cultivars of the genus Delosperma. If you are familiar with this group of plants, it is most likely thanks to the Plant Select program based in Colorado, particularly the work of Mr. Delosperma himself, Panayoti Kelaidis. Several Delosperma species are cold hardy in the Intermountain West. Thanks to their promiscuous nature, numerous crosses have occurred between species and varieties, resulting in a wide array of flower colors. And speaking of their flowers, the glistening leaves of Delosperma have nothing on their shimmering flowers, some of which may have the ability to temporarily blind you if you’re not careful. Sun is essential though, as they usually close up when shaded.

The cold hardy ice plants of the Delosperma genus are all groundcovers, maintaining a low and creeping profile. Some creep further than others. They are generally not fond of heavy clay soils, and instead prefer soil with good drainage. During the hot, dry days of summer, they appreciate a little water now and then, but watering should be cut off at the end of summer so that they aren’t sitting in saturated soils as winter approaches. They love the sun and will generally flower from late spring throughout the summer. Of course, thanks to their interesting foliage, they catch the eye and provide interest in the garden even when they aren’t flowering.

Fire Spinner® ice plant (Delosperma ‘P001S’)

Within Aizoaceae there are several species that go by the name ice plant that are not so cold hardy. Some are grown as house plants, while others are common in gardens. Still others, like Carpobrotus edulis, were once employed by land managers in California to help control erosion. However, like a number of species introduced for this purpose, C. edulis (commonly known as highway ice plant or hottentot fig) has made itself at home in areas where it wasn’t invited. It has become particularly problematic in coastal ecosystems, spreading quickly across sandy soils and outcompeting native plants. Despite being brought in to control erosion, it actually causes erosion in steep, sandy areas when its carpet-like growth becomes heavy with water and begins sliding down the hill.

highway ice plant (Carpbrotus edulis) carpeting a slope near San Diego – photo credit: Sierra Laverty

Introducing plants to our gardens that come to us from the other side of the globe should be done with caution and care. We don’t want to be responsible for the next invasive species. Since ice plant species have become problematic in California, should we be concerned about cold hardy delospermas? In trialing their plants, invasive qualities are among those that the Plant Select program watches out for, and delospermas seem pretty safe. However, as Kelaidis observes in a blog post from 2014, we should remain vigilant.

Select Resources:

Investigating the Soil Seed Bank

Near the top of the world, deep inside a snow-covered mountain located on a Norwegian island, a vault houses nearly a million packets of seeds sent in from around the world. The purpose of the Svalbard Global Seed Vault is to maintain collections of crop seeds to ensure that these important species and varieties are not lost to neglect or catastrophe. In this way, our food supply is made more secure, buffered against the unpredictability of the future. Seed banks like this can be found around the world and are essential resources for plant conservation. While some, like Svalbard, are in the business of preserving crop species, others, like the Millennium Seed Bank, are focused on preserving seeds of plants found in the wild.

Svalbard Global Seed Vault via wikimedida commons

Outside of human-built seed banks, many plants maintain their own seed banks in the soil where they grow. This is the soil seed bank, a term that refers to either a collection of seeds from numerous plant species or, simply, the seeds of a single species. All seed bearing plants pass through a period as a seed waiting for the chance to germinate. Some do this quickly, as soon as the opportunity arises, while others wait, sometimes for many years, before germinating. Plants whose seeds germinate quickly, generally do not maintain a seed bank. However, seeds that don’t germinate right away and become incorporated in the soil make up what is known as a persistent soil seed bank.

A seed is a tiny plant encased in a protective layer. Germination is not the birth of a plant; rather, the plant was born when the seed was formed. The dispersal of seeds is both a spatial and temporal phenomenon. First the seed gets to where its going via wind, water, gravity, animal assistance, or some other means. Then it waits for a good opportunity to sprout. A seed lying in wait in the soil seed bank is an example of dispersal through time. Years can pass before the seed germinates, and when it does, the plant joins the above ground plant community.

Because seeds are living plants, seeds found in the soil seed bank are members of a plant community, even though they are virtually invisible and hard to account for. Often, the above ground plant community does not represent the population of seeds found in the soil below. Conversely, seeds in a seed bank may not be representative of the plants growing above them. This is because, as mentioned earlier, not all plant species maintain soil seed banks, and those that do have differences in how long their seeds remain viable. Depending on which stage of ecological succession the plant community is in, the collection of seeds below and the plants growing above can look quite different.

Soil seed banks are difficult to study. The only way to know what is truly there is to dig up the soil and either extract all the seeds or encourage them to germinate. Thanks to ecologists like Ken Thompson, who have studied seed banks extensively for many years, there is still a lot we can say about them. First, for the seeds of a plant to persist in the soil, they must become incorporated. Few seeds can bury themselves, so those with traits that make it easy for them to slip down through the soil will have a greater chance of being buried. Thompson’s studies have shown that “persistent seeds tend to be small and compact, while short-lived seeds are normally larger and either flattened or elongate.” Persistent seeds generally weigh less than 3 milligrams and tend to lack appendages like awns that can prevent them from working their way into the soil.

The seeds of moth mullein (Verbascum blattaria) are tiny and compact and known to persist in the soil for decades as revealed in Dr. Beal’s seed viability experiment. (photo credit: wikimedia commons)

Slipping into cracks in the soil is a major way seeds move through the soil profile, but it isn’t the only way. In a study published in New Phytologist, Thompson suggests that “the association between small seeds and possession of a seed bank owes much to the activities of earthworms,” who ingest seeds at the surface and deposit them underground. Later, they may even bring them back up the same way. Ants also play a role in seed burial, as well as humans and their various activities. Some seeds, like those of Avena fatua and Erodium spp., have specialized appendages that actually help work the seeds into the soil.

Not remaining on the soil surface keeps seeds from either germinating, being eating, or being transported away to another site. Avoiding these things, they become part of the soil seed bank. But burial is only part of the story. In an article published in Functional Ecology, Thompson et al. state that burial is “an essential prelude to persistence,” but other factors like “germination requirements, dormancy mechanisms, and resistance to pathogens also contribute to persistence.” If a buried seed rots away or germinates too early, its days as a member of the soil seed bank are cut short.

The seeds of redstem filare (Erodium circutarium) have long awns that start out straight, then coil up, straighten out, and coil up again with changes in humidity. This action helps drill the seeds into the soil. (photo credit: wikimedia commons)

Soil seed banks can be found wherever plants are found – from natural areas to agricultural fields, and even in our own backyards. Thompson and others carried out a study of the soil seed banks of backyard gardens in Sheffield, UK. They collected 6 soil cores each (down to 10 centimeters deep) from 56 different gardens, and grew out the seeds found in each core to identify them. Most of the seeds recovered were from species known to have persistent seed banks, and to no surprise, the seed banks were dominated by short-lived, weedy species. The seeds were also found to be fairly evenly distributed throughout the soil cores. On this note, Thompson et al. remarked that due to “the highly disturbed nature of most gardens, regular cultivation probably ensures that seeds rapidly become distributed throughout the top 10 centimeters of soil.”

Like the seed banks we build to preserve plant species for the future, soil seed banks are an essential long-term survival strategy for many plant species. They are also an important consideration when it comes to managing weeds, which is something we will get into in a future post.

Dr. Beal’s Seed Viability Experiment

In 1879, Dr. William J. Beal buried 20 jars full of sand and seeds on the grounds of Michigan State University. He was hoping to answer questions about seed dormancy and long-term seed viability. Farmers and gardeners have often wondered: “How many years would one have to spend weeding until there are no more weeds left to pull?” Seeds only remain viable for so long, so if weeds were removed before having a chance to make more seeds, the seed bank could, theoretically, be depleted over time. This ignores, of course, the consistent and persistent introduction of weed seeds from elsewhere, but that’s beside the point. The question is still worth asking, and the study still worth doing.

When Dr. Beal set up the experiment, he expected it would last about 100 years, as one jar would be tested every 5 years. However, things changed, and Dr. Beal’s study is now in its 140th year, making it the longest-running scientific experiment to date. If things go as planned, the study will continue until at least 2100. That’s because 40 years into the study, a jar had to be extracted in the spring instead of the fall, as had been done previously, and at that point it was decided to test the remaining jars at 10 year intervals. In 1990, things changed again when the period was extended to 20 years between jars. The 15th jar was tested in 2000, which means the next test will occur in the spring of next year.

In preparing the study, Dr. Beal filled each of the 20 narrow-necked pint jars with a mixture of moist sand and 50 seeds each of 21 plant species. All but one of the species (Thuja occidentalis) were common weeds. He buried the jars upside down – “so that water would not accumulate about the seeds” – about 20 inches below ground. Near each bottle he also buried seeds of red oak and black walnut, but they all rotted away early in the study.

After the retrieval of each bottle, the sand and seed mixture is dumped into trays and exposed to conditions suitable for germination. The number of germinates are then counted and recorded. Over the years, the majority of the seeds have lost their viability. In 2000, only three species germinated  – Verbascum blattaria, a Verbascum hybrid, and Malva rotundifolia. There were only two individuals of the Verbascum hybrid, and only one Malva rotundifolia. The seeds of Verbascum blattaria, however, produced 23 individuals, suggesting that even after 120 years, the seeds of this species could potentially remain viable long into the future.

moth mullein (Verbascum blattaria)

In the 2000 test, the single seedling of Malva rotundifolia germinated after a cold treatment. Had the cold treatment not been tried, germination may not have occurred, which begs the question, how many seeds in previous studies would have germinated if subjected to additional treatments? Dr. Beal himself had wondered this, expressing that the results he had seen were “indefinite and far from satisfactory.” He admitted that he had “never felt certain that [he] had induced all sound seeds to germinate.”

There are also some questions about the seeds themselves. For example, the authors of the 2000 report speculate that poor germination seen in Malva rotundifolia over most of the study period could be “the result of poor seed set rather than loss of long-term viability.” The presence of a Verbascum hybrid also calls into question the original source of those particular seeds. A report published in 1922 questions whether or not the seeds of Thuja occidentalis were ever actually added to the jars, and also expresses uncertainty about the identify of a couple other species in the study.

Despite these minor issues, Dr. Beal’s study has shed a great deal of light on questions of seed dormancy and long-term seed viability and has inspired numerous related studies. While questions about weeds were the inspiration for the study, the things we have been able to learn about seed banks has implications beyond agriculture. Seed bank dynamics are particularly important in conservation and restoration. If plants that have disappeared due to human activity have maintained a seed bank in the soil, there is potential for the original population to be restored.

In future posts we will dive deeper into seed banks, seed dormancy, and germination. In the meantime, you can read more about Dr. Beal’s seed viability study by visiting the following links:

Eating Weeds: Blue Mustard

Spring is here, and it’s time to start eating weeds again. One of the earliest edible weeds to emerge in the spring is Chorispora tenella, commonly known by many names including blue mustard, crossflower, and musk mustard. Introduced to North America from Russia and southwestern Asia, this annual mustard has become commonplace in disturbed areas, and is particularly fond of sunny, dry spots with poor soil. It can become problematic in agricultural areas, but to those who enjoy eating it, seeing it in large quantities isn’t necessarily viewed as a problem.

rosettes of blue mustard (Chorispora tenella)

The plant starts off as a rosette. Identifying it can be challenging because the shape of the leaves and leaf margins can be so variable. Leaves can either be lance-shaped with a rounded tip or more of an egg shape. Leaf margins are usually wavy and can be deeply lobed to mildly lobed or not lobed at all. Leaves are semi-succulent and usually covered sparsely in sticky hairs, a condition that botanists refer to as glandular.

A leafy flower stalk rises from the rosette and reaches between 6 and 18 inches tall. Like all plants in the mustard family, the flowers are four-petaled and cross-shaped. They are about a half inch across and pale purple to blue in color. Soon they turn into long, slender seed pods that break apart into several two-seeded sections. Splitting apart crosswise like a pill capsule rather than lengthwise is an unusual trait for a plant in the mustard family.

blue mustard (Chorispora tenella)

Multiple sources comment on the smell of the plant. Weeds of North America calls it “ill-scented.” Its Wikipedia entry refers to it as having “a strong scent which is generally considered unpleasant.” The blog Hunger and Thirst comments on its “wet dish rag” smell, and Southwest Colorado Wildflowers claims that its “peculiar odor” is akin to warm, melting crayons. Weeds of the West says it has a “disagreeable odor,” and warns of the funny tasting milk that results when cows eat it. All this to say that the plant is notorious for smelling bad; however, I have yet to detect the smell. My sense of smell isn’t my greatest strength, which probably explains why I’m not picking up the scent. It could also be because I haven’t encountered it growing in large enough quantities in a single location. Maybe I’m just not getting a strong enough whiff.

Regardless of its smell, for those of us inclined to eat weeds, the scent doesn’t seem to turn us away. The entire plant is edible, but the leaves are probably the part most commonly consumed. The leaves are thick and have a mushroom-like taste to them. They also have a radish or horseradish spiciness akin to arugula, a fellow member of the mustard family. I haven’t found them to be particularly spicy, but I think the spiciness depends on what stage the plant is in when the leaves are harvested. I have only eaten the leaves of very young plants.

The leaves are great in salads and sandwiches, and can also be sauteed, steamed, or fried. I borrowed Backyard Forager’s idea and tried them in finger sandwiches, because who can resist tiny sandwiches? I added cucumber to mine and thought they were delicious. If you’re new to eating weeds, blue mustard is a pretty safe bet to start with – a gateway weed, if you will.

blue mustard and cucumber finger sandwiches

For more information about blue mustard, go here.

Eating Weeds 2018:

Poisonous Plants: Red Squill

Humans have been at war with rats since time immemorial. Ridding ourselves of their nuisance behavior is increasingly unlikely, and in fact, some scientists believe that, following human extinction, rats will be poised to take our place as the most dominant species on earth. Despite being thwarted repeatedly, we make tireless attempts to control rat populations. One major weapon in our arsenal is poison, and one of the most popular rat poisons was derived from a plant with a formidable bulb.

Urginea maritima (known synonymously as Drimia maritima, among other Latin names) is a geophyte native to the Mediterranean Basin, where it survives the hot, dry summer months by going dormant, waiting things out underground. Growth occurs in the cooler months, its bulb expanding annually before it finally flowers late one year after reaching at least 6 years old. Its flower stalk rises to as tall as 2 meters, extending heavenward from a bulb that can weigh as much as a kilogram. Its inflorescence is long, narrow, and loaded with small flowers that are generally white, but sometimes pink or red.

The oversized bulb of Urginea maritima — via wikimedia commons

Urginea maritima is commonly known as red squill or white squill (and sometimes simply, squill). Other common names include sea onion, sea squill, and giant squill. It is related the squill referred to in the Harry Potter universe, which is known botanically as Scilla. However, plants in the genus Scilla are much more dimunutive and generally flower in the spring rather than the fall. Like red squill, Scilla species are known to be poisonous; however, they don’t have the reputation for producing deadly rat poison that red squill does.

Like so many poisonous plants, red squill has a long history of being used medicinally to treat all sorts of ailments. As with any folk remedy or natural medicine, a doctor should be consulted before attempting to treat oneself or others. A 1995 report tells of a woman who ate red squill bulbs to treat her arthritic pain. She exhibited symptoms characteristic of ingesting cardiac glycosides – the toxic compound found in red squill – including nausea, vomiting, and seizures. She died 30 hours after eating the bulbs.

red squill (Urginea maritima) — via wikimedia commons

Toxic compounds are found throughout the plant, but are particularly concentrated in the bulb (especially its core) and the roots. Toxicity is at its highest during summer dormancy and when the plant is flowering and fruiting. The compound used to poison rats is called scilliroside. Bulbs are harvested in the summer, chopped up, and dried. The chips are then ground down to a powder and added to rat bait. Results are highly variable, so to increase its effectiveness, a concentrate can be made by isolating the toxic compound using solvents.

Red squill was introduced to southern California in the 1940’s as a potential agricultural crop. The region’s Mediterranean climate and the plant’s drought tolerance made it ideal for the area. The bulbs can be grown for manufacturing rat poison, and the flowers harvested for the cut flower industry. Breeding efforts have been made to produce highly toxic varieties of red squill for rat poison production.

the flowers of red squill (Urginea maritima) — via wikimedia commons

Around the time red squill was being evaluated as an agricultural crop, studies were done not only on its toxicity to rats, but to other animals as well. A 1949 article details trials of a red squill derived poison called Silmurine. It was fed to rats as well as a selection of farm animals.  Results of the study where “not wholly satisfactory” when it came to poisoning rats. Silmurine was less effective on Rattus rattus than it was on Rattus norvegicus. Thankfully, however, it was found to be relatively safe for the domestic animals it was administered to. Most puked it up or avoided it. Two humans accidentally became part of the study when they inadvertently inhaled the poison powder. Ten hours later they experienced headaches, vomiting, and diarrhea, “followed by lethargy and loss of appetite,” but “no prolonged effects.”

Vomiting is key. Ingesting scilliroside induces vomiting, which helps expel the poison. However, rodents can’t vomit (surprisingly), which is why the poison is generally effective on them.

Today, squill is available as an ornamental plant for the adventurous gardener. For more about that, check out this video featuring a squill farmer:

More Poisonous Plants posts on Awkward Botany: