Podcast Review: Botanical Mystery Tour

My interest is piqued any time plants are featured or plugged in popular culture. Hence my ongoing series of posts, Botany in Popular Culture, featuring Futurama, Saga of the Swamp Thing, etc. Plants just don’t get enough airtime, so it must be celebrated when they do. Which is why I was excited to learn about Chicago Botanic Garden‘s new podcast, Botanical Mystery Tour, in which the plants referenced in pop culture take center stage.

The hosts, as they state in each episode’s introduction, “dive into the botany hidden in our favorite stories.” To help with the discussion, they bring in experts that work at Chicago Botanic Garden to explore the science (and fiction) behind the plant references. In addition to discussing pop culture and the related science, the guests share details about the work they do at the Garden and some of the research they are working on.

In the first episode, Jasmine and Erica ask Paul CaraDonna about the drone bees featured in an episode of Black Mirror. Since many bee species are in decline, will we have to resort to employing robot bees to pollinate plants that rely on bee-assisted pollination? A great discussion about native bees and colony collapse disorder ensues.

(But maybe the idea of autonomous drone insects isn’t too far-fetched…)

In episode two, the hosts ask why humans are so obsessed with corpse flowers. Thousands of people flock to botanical gardens to see these humongous, stinky flowers on the rare occasions they are in bloom, so what is so appealing about Amorphophallus titanum? Patti Vitt joins the discussion to share details about this fascinating plant.

A corpse flower in bloom is a brief and uncommon occurrence, reminiscent of the Sumatran Century Flower in The Simpsons and the 40 Year Orchid in Dennis the Menace.

 

The third episode features the sarlaccs of Star Wars. It turns out, sarlaccs are carnivorous plants. This discovery spawns an interesting discussion with horticulturist Tom Weaver about what defines a carnivorous plant and the various ways that different carnivorous plant species capture and kill their prey.

The fourth (and latest) episode is an exploration into the magical world of mushrooms. In Alice in Wonderland, Alice encounters a large, hookah-smoking caterpillar sitting atop a giant mushroom. Are there mushrooms big enough that a person could actually sit on them like Alice does? Greg Mueller joins the podcast to address this and many other mycology-based questions. The conversation includes a great discussion about why a botanical garden (whose main focus is plants) would be interested in fungus.

The discussions in this podcast are fun and enlightening. The hosts shine the spotlight on often overlooked characters in popular media, and with the help of their guests, lead captivating conversations about the science related to these characters. With only a handful of episodes available so far, it will be easy to get caught up. And then you, like me, will find yourself anxiously looking forward to embarking on another Botanical Mystery Tour.

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Is there a plant-themed podcast or podcast episode you would like to recommend? Please do so in the comment section below.

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How Pitcher Plants Eat Bugs (Frog Optional)

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A few months ago at work I captured this photo of a frog inside of a pitcher plant. Do you see it? It is pretty well camouflaged and poking its head out just enough to intercept curious insects lured in by the promise of nectar, eating them before they can make their way into the tube. Either way, approaching insects are about to meet their fate. Whether by plant or by frog, they are destined to be consumed lest they turn away in time.

This frog was hiding inside the modified leaf of a species of Sarracenia, a carnivorous plant commonly known as a North American pitcher plant. There are at least eight species of Sarracenia, all of which naturally occur in the southeastern region of the United States. One species, Sarracenia purpurea, also occurs in the northeast, the upper Midwest, and throughout much of Canada. Sarracenia is in the family Sarraceniaceae along with two other genera of pitcher plants, Darlingtonia (the cobra plant, native to northern California and southern Oregon) and Heliamphora (the sun pitchers, native to South America). Plants in this family are not to be confused with the distantly related tropical pitcher plants which are in the genus Nepenthes (family Nepentheaceae).

The natural habitats of Sarracenia are sunny, open areas that remain permanently wet, including meadows, savannahs, fens, and swamps. The soils are acidic, nutrient poor, and typically composed of sandy peat commonly derived from sphagnum moss. In the southeast, less than 5% of the original (pre-European settlement) Sarracenia habitat remains, threatening its survival in the wild. Sarracenia oreophila (green pitcher plant) is currently listed as critically endangered on the IUCN Red List.

Flowering occurs in the spring, usually before pitchers form. Individual flowers are formed on tall stalks that rise straight up and then bend at the very top, hanging the flower upside down. Early flowering and tall flower stalks help prevent pollinating insects from being consumed by the plant. In his book The Savage Garden, Peter D’Amato describes the flowers as “showy, brilliant, and very unusual – a wonderful bonus to an already handsome class of foliage plants.” The flowers are either yellow or a shade of red and last about two weeks, after which the petals drop and a seed pod forms. Seeds are released from the fruits in the fall.

Flower of Sarracenia rubra (sweet pitcherplant) - photo credit: www.eol.org

Flower of Sarracenia rubra (sweet pitcher plant) – photo credit: www.eol.org

D’Amato writes that Sarracenia are among the “most ravenous” plants, with each leaf having the potential of trapping “thousands of nasty insects.” In some cases pitchers even flop over, heavy with the weight of bugs inside them. The specifics of capturing and killing insects varies between species of Sarracenia, but in general prey is lured to the opening of the pitcher with a combination of nectar, scent, and color. Upon entering the tube, gravity, waxy surfaces, drugs, and hairs force the captives downward where they are eventually consumed by enzymes and microbes. Digested insects provide the plant with nutrients necessary for growth – nutrients that otherwise are taken up by the roots of plants that occur in more nutrient rich soils.

Sarracenia purpurea (purple pitcher plant) is unique in that its pitchers lack a “hood” or “lid” – a standard feature of other species of Sarracenia that helps keep rain from entering the pitchers. Instead, the pitchers fill with water and insects are killed by drowning. The most brutal killer is probably Sarracenia psittacina (parrot pitcher plant) which has an additional opening inside of its pitcher. The opening is small and difficult to find again once an insect is on the wrong side of it. The inside walls of the pitcher are covered in long, sharp, downward pointing hairs, and the struggling insect is pierced repeatedly by the hairs as it makes its way to the bottom of the tube to be digested.

Hoodless pitchers of Sarracenia purpurea (photo credit: www.eol.org)

Hoodless pitchers of Sarracenia purpurea (photo credit: www.eol.org)

Hooded pitchers of Sarracenia leucophylla (photo credit: www.eol.org)

Hooded pitchers of Sarracenia leucophylla (photo credit: www.eol.org)

According to D’Amato, “the Sarracenia are one of the simplest carnivorous plants to grow, and certainly among the most fun and rewarding.” Learn more about growing North American pitcher plants by consulting D’Amato’s book and/or by visiting the website of the International Carnivorous Plant Society.

Want to learn more about Sarracenia? The Plants are Cool, Too! web series has a great video about them:

Other carnivorous plant posts:

Venus Flytrap: A Species of Special Concern

The Venus flytrap is likely the most popular and well-known (as well as the most purchased and widely owned) of any carnivorous plant. It is a proud representative of a diverse group of plants that continues to astound most everyone from plant experts to plant amateurs and even the plant ambivalent. With its leaves shaped like gaping mouths with sharp teeth and its ability to snap shut and devour insect prey, it is a remarkable species, but would you believe that it is also a rare one?

The Venus flytrap (Dionaea muscipula) is native to a small region on the east coast of the United States near the border of North and South Carolina. Its range extends to about a 100 mile radius from Wilmington, NC. Within this region, the habitat of the Venus flytrap is mainly wet savannahs with sandy, peaty, acidic soils on the edges of swamps and fens. Thus with its limited range and specific habitat requirements, the Venus flytrap has always been a rare species, even before it became a popular houseplant.

Apart from being naturally rare, the Venus flytrap now faces numerous threats to its continued survival in the wild. The obvious one is its popularity, which has led to the harvesting of hundreds of thousands of wild plants to be cultivated and sold in the plant trade. Other threats involve its habitat. Wetlands are one of the most threatened ecosystems. They are frequently drained and developed for real estate, agriculture, and recreation, and they are regular victims of pollution and exotic species invasions. The wetlands that Venus flytraps call their home are no exception. Additionally, naturally occurring fires are being suppressed in this region, allowing larger plants normally kept in check by occasional fires to thrive and choke out low-growing Venus flytraps.

Despite these threats, the Venus flytrap has not yet been listed as a federally endangered species. However, it is currently listed as a species of special concern in North Carolina and is listed as Vulnerable on the IUCN Red List. Fortunately, wildlife officers in North Carolina do issue citations to anyone caught illegally harvesting Venus flytraps in order to deter such activity.

venus flytrap

Dionaea muscipula   © 2006 Barry Rice

If you are interested in owning a Venus flytrap, make certain that you are purchasing a nursery grown plant and not a wild harvested one. The plant label should specify this. To be sure you are purchasing a nursery grown plant, look for cultivar names, like ‘Red Dragon’ or ‘Royal Red’ (and many others). These are plant varieties that have been bred in tissue culture labs from cultivated plants.

To learn more about the Venus flytrap and its current conservation concerns, see this Encyclopedia of Life page.

Related Posts:

Northern Pitcher Plants: A Model for Understanding Food Webs

The Sundews

Overwintering Carnivorous Plants

Wetlands!

Overwintering Carnivorous Plants

I once assumed that all carnivorous plants were tropical. I’m not sure exactly why. Perhaps it’s because they are so bizarre (both in their appearance and behavior), nothing like the plants that I was accustomed to seeing growing up in the Intermountain West. Or maybe it’s because the one carnivorous plant that I was most familiar with, the Venus flytrap, is commonly sold in the houseplant section of department stores. If it’s a houseplant, it must be tropical, right?

Eventually I learned the truth. Much to my surprise, there are numerous carnivorous plants that are native to temperate regions – in fact, carnivorous plants can be found on every continent except Antarctica. Even more surprising, Venus flytraps are temperate plants! It’s true. They are native to a small region in North Carolina, within about a 100-mile radius from Wilmington.

Plant species native to temperate regions require a dormant period. In the winter, the temperature drops, day length decreases, and, in some cases, drought ensues. During this time plants go dormant – they hibernate – and wait for the warmer, brighter days of spring to continue on with their metabolic and reproductive processes. It’s a period of rest.

Carnivorous plants native to temperate regions fall into this category – they require a period of dormancy in order to stay healthy and productive. In his book, The Savage Garden, Peter D’Amato asserts that, “Dormancy in carnivorous plants that require it must be respected and permitted to occur. Otherwise, the plant may die.” He goes on to say that a Venus flytrap grown year-round in a warm environment exposed to grow lights for the majority of the day “will eventually get sickly and die.” In short, these plants need a rest, and so it’s best to grow them outdoors where they will be exposed to the elements, thereby entering a period of dormancy as nature intended.

Venus flytraps (Dionaea spp.), North American pitcher plants (Sarracenia spp.), and serveral species of sundews (Drosera spp.) can all be grown outdoors year-round in temperate climates. In order to ensure their survival, it’s best to give them a little protection during the winter months – especially when temperatures are projected to reach below 20 degrees for several consecutive nights.

Recently, I helped put the carnivorous plant display at Idaho Botanical Garden to bed for the winter. The carnivorous plants are being grown in an old stock water trough. First we cut back the plants, reducing their size by at least a third and being especially careful to remove dead or rotting plant material. Next, we placed several straw bales around the sides of the trough. Then we covered the plants with three layers of material: black plastic, evergreen boughs, and dead leaves. Dave Nelson, of killergarden.com, suggests a similar winterizing treatment: “the plants can be placed on the ground, covered with a tarp, and then covered with six inches or so of dead leaves, pine needles, straw, or other mulch.”

After the threat of freezing temperatures has passed, the plants can be uncovered. As temperatures continue to warm, the plants will awake from their dormant state and prepare themselves for another spectacular season of devouring bugs and looking awesome.

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Carnivorous Plant Display at Idaho Botanical Garden

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Winterized Carnivorous Plant Display

A final word from Paul D’Amato: “You should never force a carnivorous plant into growth during a season when it should be resting.”

Interview with Peter D’Amato of The Savage Garden

In my last post about sundews, I referenced a book about carnivorous plants called, The Savage Garden, by Peter D’Amato. Earlier this month, a revised edition of The Savage Garden was released by Ten Speed Press. Recently, D’Amato appeared on Real Dirt, a garden podcast hosted by Ken Druse, to tell his story, promote the revised edition of his book, and talk about carnivorous plant cultivation. It’s a fascinating discussion, and I highly recommend checking it out.

real dirt

Also, check out the website for Peter D’Amato’s carnivorous plant nursery, California Carnivores.

The Sundews

Earlier this year, I wrote about northern pitcher plants and how they are helping us to better understand food webs. At that time I promised future posts about carnivorous plants, so I have decided to write about sundews, the only carnivorous plant that I currently have in my collection.

Sundews are members of the genus Drosera and are in the family Droseraceae (the same family as the Venus flytrap). With as many as 194 species, Drosera is one of the largest and most diverse genera of carnivorous plants. Sundews can be found in a wide variety of climates and on nearly every continent, from subarctic Alaska to tropical Brazil. They can be as small as a penny or as big as a small shrub. Their leaves form rosettes and come in numerous shapes and sizes, including circular, wedge-shaped, oval,  forked, fern-like, and grass-like. Drosera flowers are also quite diverse, but typically they are flat, five-petaled, white or pink, and appear in clusters at the top of a tall stalk.

As described so far, you may be thinking that sundews sound quite simple and innocent, but this is certainly not the case. Covering the surfaces of Drosera leaves are dozens of hair-like filaments. At the end of each filament (or tentacle) is a gland, which produces a small drop of clear and very sticky dew. Attracted to the glistening dew and mistaking it for plant nectar, insects fly into it and find themselves instantly stuck. Struggling to get away, an insect may tear off body parts as it flails about, only to fall into other nearby dew droplets, worsening its ensnarement and ensuring its fate.

In his book, The Savage Garden, Peter D’Amato describes it this way:

“Sundews are innocent-looking and pretty, their delicate leaves sparkling with the promise of sweet nectar, but the foolish insect curious enough to give a sundew the slightest touch will suddenly find itself caught in a living nightmare. Doomed to a horrible death, the insect may struggle for a blessed few minutes or suffer for untold hours as it tries to break free of ensnaring, suffocating glue, grasping tentacles, and burning acids and enzymes; meanwhile, its precious bodily fluids are being slowly sucked dry.”

As the sticky dew attracts and then traps the insects, and the tentacles that support the dew help to further ensnare them, imminent death comes in a variety of ways. The most common for small insects is suffocation, as the glue almost immediately covers up the breathing holes on their abdomens. Larger insects that manage to avoid bodily contact with the glue will instead dangle from the plant and die of starvation or exhaustion. Those that break free, losing an appendage or appendages in the process, usually don’t last long after that and are often trapped and killed by spiders who build their webs around sundews in order to take advantage of such occasions. The leaves of some sundews curl up around their prey, not necessarily to further ensnare them, but to surround them with the largest possible number of glands which will help quicken the consumption and digestion process. By now you can see that as innocent and delicate as they may appear, sundews are in fact about as brutal and unforgiving as they come.

If you’d like to learn more about sundews and other carnivorous plants, including information on how to grow them, I highly recommend D’Amato’s book (The Savage Garden). It’s a fascinating and informative read, and the reality of the natural world described therein will astound you.

Drosera chrysolepis

Drosera chrysolepis, photo credit: wikimedia commons

Northern Pitcher Plant: A model for understanding food webs

Carnivorous plants are endlessly fascinating. Even people who aren’t typically interested in plants are likely to find plants that eat animals to be of some interest. These plants not only provide fascination for plant lovers and the plant ambivalent alike, but they are also of great interest to science, providing insight into the workings of the world beyond the swamps and bogs that they inhabit.

A recent study published in the journal, Oikos, examined the complex food web that exists inside the northern pitcher plant (Sarracenia purpurea) in order to come to a better understanding of food webs in general and to construct a model that will aid in further research involving food webs in all types of ecosystems.

The food web that exists inside a pitcher plant is quite interesting. The tubular leaves of the pitcher plant capture rain water and draw in a variety of insects including beetles, ants, and flies. The pool of water also becomes home to the larvae of midges, mosquitoes, and flesh flies, as well as various other tiny creatures including rotifers, mites, copepods, nematodes, and multicellular algae. And thus begins a complex food cycle. Midge larvae attack the drowning insects and tear them to pieces, then bacteria go after the tiny insect parts, after which rotifers consume the bacteria. Finally, the walls of the pitcher plant absorb the waste of the rotifers. Meanwhile, fly larvae consume the rotifers, midge larvae, and other fly larvae, while bacteria is being consumed by all participants.

You can see why this food web is an ideal subject of study. Not only is it complex, with numerous players, but it is also all taking place in a small, confined space – easily observable. By studying such a system, models can be derived for larger, more widespread food webs.

Carnivorous plants have diverse mechanisms for extracting nutrients from other living things – this is just one of those mechanisms. I will plan to profile other carnivorous plants on this blog, because like I said, they are endlessly fascinating. Meanwhile, you can read more about this particular study at Science Daily.

northern pitcher plant

northern pitcher plants (Sarracenia purpurea) photo credit: wikimedia commons