About Melissa Dowland

Coordinator of Teacher Education North Carolina Museum of Natural Sciences www.naturalsciences.org

Flower Parts: The Iris’ Have It

In the Spring a fuller crimson comes upon the robin’s breast;
In the Spring the wanton lapwing gets himself another crest;

In the Spring a livelier iris changes on the burnish’d dove;
In the Spring a young man’s fancy lightly turns to thoughts of love.

~Alfred, Lord Tennyson
Siberian iris, Iris siberica

I’ve been meaning to take a look at this more common backyard flower for a couple weeks now, ever since the Siberian iris (Iris siberica) began blooming in our yard. It’s almost done now, but the native blue flag iris (Iris virginica) is just beginning to open up in big numbers in our pond, so we should have irises around for a number of weeks yet.

Iris is one of those flowers that a lot of people have in their yard, so it might be a little more accessible to some to take a closer look at than wood poppy or Jack-in-the-pulpit. And it has large parts that are fairly easy to see… but they’re a little bit complicated, and figuring out which parts are which was more challenging than I expected!

As usual, I started with a hunt for the sepals. But my typical sepal-finding technique, seeing which parts enclosed the flower before opening, didn’t work quite as well as it has for some of the others flowers I’ve examined. The iris flower emerges from a swollen fold in the leaves of the plant (there’s probably a proper botanical term for this but I don’t know what it is!).

Opening iris bloom

I was pretty sure that the green around the flower was leaf and not sepal. So I had to refer back to the real definition of a sepal, which is the outer whorl of the corolla (petals + sepals). Here’s the base of the flower where the sepals and petals join the stem:

Base of iris flower

This was still confounding, as it looks like all six parts of the corolla are attached at the same level on the stem. Finally, I had to give in and check out a favorite flower reference, A Guide to Enjoying Wildflowers by Donald and Lillian Stokes. According to Stokes, the three larger and frillier parts are the sepals and the smaller, more upright ones are the petals.

The lowest part is this photo is the sepal. Two of the petals are to the right and left of the sepal. Ignore the bit in the middle, directly above the sepal, for the moment…

So with an iris, it seems the showiest “petals” are actually sepals! I found another good botanical word to describe this: the sepals are “petaloid.” The three petals are the slightly more modest, plainer parts situated between the sepals (you can see them well in the very first picture).

I felt like I needed a little more proof to help me understand this all better, so I went out for a look at our blue flag iris, which is just beginning to open up and had a better variety of flower buds.

On this larger flower bud, note the green color at the base of the sepals. If you refer back to the photo of the base of the flower, you can see how there is some green at the outside base of the sepals that is lacking on the petals. This is the case on the open blue flag iris flowers as well. This helped me feel more confident in what I read in the Stokes guide – that the larger, showier petal-like structures are the sepals. Phew. Sepals are definitely the toughest!

The reproductive structures in an iris are also a bit different from some of the other flowers I’ve looked at. The stamen has the fairly typically eye shadow applicator appearance, but it hides under another petal-like structure. It starts out fairly elongated and smooth, but shrinks and shrivels as it produces its white pollen (see below).

The white, pollen-covered anther at the tip of the stamen hides under another petal-like structure.

So what’s the petal-like part above the stamen? It turns out that’s the pistil. Or more technically, applying my new vocabulary, a petaloid pistil. The curved lip directly above the anther (pollen-producing part of the stamen) is actually the stigma. The feathery bit above the stigma (the end of the petaloid part) is part of the style (the part that connects the stigma to the ovary). As a pollinator crawls down the “throat” of the flower, following the striped nectar guides on the sepal, any pollen it’s carrying on its back is scraped off by the stigma. Then it hits the anther and picks up more pollen to carry on to the next flower. Mike described this process well in a post about one of our native iris species, the crested dwarf iris, in a post from a few years ago. In both the crested dwarf iris and the blue flag iris, the pistil lays tightly against the sepal, so a pollinator really has to force its way in. On the Siberian iris, the pistil is more upright, providing easier access to the stigma and anther, but perhaps it is less efficient at ensuring pollination?

If all goes well, the flower is pollinated and a pollen tube grows down the petal-like style to the ovary. In our yard, many of those ovaries are already beginning to swell.

Ripening ovary; the shriveled brown bit attached at the tip is the former flower!

Inside, the ovules are developing, getting ready to seed in the next round of iris.

Dissected ovary with developing seeds.

Of course, this species tends to spread more easily via underground rhizomes, making it a prolific perennial in our yard!

Jack… or Jill… in the Pulpit?

The Lord chose to reveal his power and his love through two human faces: the face of his divine Son made man and the face of a creature, a woman, Mary. Women make their contribution to the Church in a way that is properly theirs, by making present the tender strength of Mary, the Mother… In a synodal Church, those women who in fact have a central part to play in Amazonian communities should have access to positions, including ecclesial services, that do not entail Holy Orders and that can better signify the role that is theirs.This would also allow women to have a real and effective impact on the organization, the most important decisions and the direction of communities, while continuing to do so in a way that reflects their womanhood.

~Pope Francis, on the ordination of women, in “Querida Amazonia”

Women may still not be allowed to be Catholic priests, but in the plant world, they’ve taken their place at the pulpit – Jack-in-the-Pulpit’s pulpit, that is! We have several clumps of this interesting native plant in our yard, and they’ve started to produce their strange blooms just in time for the Easter edition of the flower parts series!

Jack at his pulpit. And no, that’s not a heavenly light coming down… it’s just the camera flash!

Jack-in-the-pulpit (Arisaema triphyllum) is perhaps one of the strangest flowers I’ve examined to date. It’s dioecious, meaning it has male and female flowers on different plants. Not only that, but depending on how healthy the plant is, it will change its sex: it can produce no flowers, male flowers, or female flowers from one year to the next. Because producing fruit takes the most energy, only very healthy, well-stocked plants will produce female flowers. Typically, female flowers are borne on plants with two leaves. Male flowers take less energy to produce than female flowers, and they are typically borne on plants with only one leaf.

That’s not poison ivy! It’s the compound leaf of a jack-in-the pulpit plant. So make sure you double-check your identification so as to not remove one of these amazing, native wildflowers from your yard accidentally!

I was reticent to remove one of the blooms because we don’t have too many in our yard. A quick survey showed that we have about 10 male flowers and only 3 or 4 female flowers. But Mike found one that had been cut by a rabbit, which gave me a chance to examine it further.

Jack-in-the-pulpit male inflorescence

The two most noticeable parts of the Jack “flower” are the hood (the pulpit) and Jack himself, inside the pulpit. These two parts caused me to learn yet another few botanical terms. The pulpit is technically a spathe, which, according to the trusty Plant Identification Terminology: An Illustrated Guide (by Harris and Harris) is a type of bract that often encloses the flower. (Remember the dogwood bracts from my previous post?) Inside, “Jack” is technically called a spadix which is “a spike with small flowers crowded on a thickened axis.” (And I thought spadix were those tight shorts I used to wear under my soccer uniform…:)

One feature to note is the small hole at the bottom of the inflorescence, right where the bract meets the stem.

Hole at base of bract on a male flower

Mike knew that this hole was only a feature of the males. For comparison, here’s the base of a female.

Female flower – note the lack of a hole at the base of the bract.

More on this difference in a moment… For now, back to the male flower. Since the rabbit had done its dirty work of cutting the inflorescence, I went ahead and took advantage of having it in hand and dissected it to show the flowers inside.

Male flowers

With the spathe removed, you get a clear view of the spadix. The swollen bits at the bottom that look a little bit like snail eye tentacles are the male flowers.

Even closer view of the male flowers

The flowers are lacking sepals and petals. The tentacle-y bits are the stamens. Because they’re male flowers, they don’t have a pistil either. As the flower develops, the stamens will begin to produce pollen. I read on the New York Botanical Garden website that each male flower has 4 stamens. In my pictures, it looks as though there are two tentacles per flower, and if you click on the photo and enlarge it as much as possible, it indeed looks like there’s two round bits at the tip of each tentacle, which would mean 4 stamens per flower.

Mike and I went outside to take a look at a female inflorescence. This was a little tricky because I didn’t want to pick it, but still wanted to be able to show the flowers down inside the spathe. Here’s a female, rising from a plant with two leaves.

Female inflorescence

Again, note the lack of a hole at the bottom of the bract. We were in for a surprise as we began to examine the flower more closely. Mike helped me pull back the top of the spathe to take pictures down the gullet of the flower… and lo and behold, we found a cauldron of gnats!

I had read in the always-informative Stokes Nature Guides: A Guide to Enjoying Wildflowers by Donald and Lillian Stokes that there might be some flies, likely fungus gnats, inside of the flower. However, I wasn’t expecting quite the swarm we found! Apparently, the flowers emit an odor that mimics the scent of fungus, which is where these flies like to lay their eggs. The hooded spathe, with lines that guide insects toward the bottom and lighter coloration at the bottom, lures flies in. Think about how, if you have a fly in your house, it tends to hover around your windows – flies tend to seek light. So having more light at the bottom of the tube means the flies will fly to the bottom and get trapped. This plant functions very similarly to a hooded pitcher plant, which acts in much the same way (minus the fungus smell).

This is where that hole at the bottom of the bract comes in handy. On the male flowers, the gnats roam around and get coated in pollen… but most eventually find their way out via that hole. In the female flower, there’s no exit hole, and the gnats may never find their way out, poor souls. But this likely helps ensure that the female flowers are pollinated. Fortunately for the flies, though perhaps not the flowers, as we continued to manipulate the plant to try to expose the female flowers, many of the gnats were able to escape, though most stuck around and kept trying to get back in!

After much more uncomfortable kneeling and fingers and hands getting in the way of pictures, with Mike’s help I was able to get some photos of female flowers.

Female flowers

You can see in this image each female flower is basically a swollen green ovary with a yellowish knob protruding – the knob is the stigma.

I think I owe you all a note on botanical terminology here. In all of my flower parts posts, I’ve been careful in my use of the word “flower.” For instance, I called the dogwood “flower” a bloom, blossom, or inflorescence and NOT a flower because the flowers are actually the tiny parts in the middle. However, in this post, I’ve found it harder not to call the inflorescence a flower. The less-technical “bloom” and “blossom” just don’t seem appropriate in this case, and inflorescence is quite a bulky word. However, technically, this mostly green leaf-like thing is not a flower, it’s an inflorescence. The flowers are what’s at the bottom of the spadix: the tentacle-like male flowers or swollen, stigma-bearing female flowers. I hope the botanists of the world will excuse my imprecise use of terminology in this case!

Even closer look at the female flowers… and one of their pollinators!

Hopefully these female flowers got pollinated by the fungus gnats before Mike and I let them all escape. If so, this plant will produce a beautiful cluster of berries in the fall, when the spadix will wither at the top, and each ovary will swell and turn brilliant red.

Keep an eye out for these amazing plants on your next socially distant hike in the woods, and if you see one, take a careful look to see if it’s Jack, or maybe Jill, in the pulpit!

Plant Parts Part 3: Wild Columbine

Ephemeral

Delicate, perfumed phlox;
A mist of columbine, clinging to earth;
Phoebe’s gravelly voice,
Titmouse — tender, sweet;
A dogwood cloud hover above
Vibrant, fresh leaves.

Fleeting
Falling flowers, already spent;
A garden, no longer my own.

A spring, a garden, will come again;
At home in the hope, the beauty.

Bittersweet
and fast-fading.

Always returning!

Mike has shared some of my poetry on his blog in the past; the poem above is another of mine. In fact, it’s the first I wrote as an adult. I went to a poetry session at an Outdoor Classroom Symposium at the NC Botanical Garden that was taught by a couple of teachers from South Carolina. The teachers gave us a few templates to get started, and sent us out along the garden paths to write. I found a spot amid a patch of beautiful columbine flowers. The first activity was simple – use your senses to observe the world around you, and pay attention to how that makes you feel. The poem above is the result of that short, sweet writing exercise. I have used the same simple steps many times since then in my own writing, and I’ve shared that activity with numerous teachers through my work. I’m incredibly grateful to those two teachers for reintroducing me to the world of poetry-writing!

But now, it’s time for our next flower parts adventure… this time we’ll take a close look at wild columbine (Aquilegia canadensis). Wild columbine is one of my favorite spring wildflowers, and we have an abundance of it in our yard. The flowers hang on delicate stems and look like they’re floating above the ground. Each plant produces numerous blossoms over the course of  at least a month in our yard. In fact, a couple of years ago, one of the earliest blooms managed to get caught in a late winter snowstorm…

Wild Columbine in snow, March 12, 2017

Because its so ubiquitous, it was an early target for my plant parts explorations – I didn’t feel too terrible taking a few blossoms off the plants when they were so numerous! Like the wood poppy, it is a simple flower, but because of the odd shape of some of its parts, it’s a little more challenging. As with the wood poppy and dogwood flowers, my first task was to find the sepals.

Columbine flower
Columbine flower

Given the overlapping nature of the flower’s structure, this was tricky. Which are the sepals, which are the petals? I took off one of each to see if I could tell…

Columbine flower with two outer parts removed
Columbine flower with 1 sepal and 1 petal removed… but which is which?

It was still difficult to tell which was which, even after removing one of each part, though it seemed as though the smaller, leaf-shaped parts were attached higher up on the stem than the long, spurred ones, which would make them the sepals. I looked for some flower buds for confirmation, and indeed, the leaf-shaped part enclosed the bud before it opened. Mystery solved!

In these two images, you can see how the petals’ spurs extend and start turning red very early in the flower’s development. In the image on the right, you can even notice the developing stamens inside the flower bud; and in the right-hand image, the elongated stalks extending out of the flower bud are the undeveloped pistils (more on that in a moment). The spurred petals have a nectar reward in the bulb at the top where long-tongued pollinators like butterflies and hummingbirds can access it (while conveniently rubbing their bodies or heads on the stamens or pistils).

Since columbine blooms for so long in our yard, it was easy to trace the development of different parts of the flower by finding a sequence of ripening flowers.

In an early bloom, the stamens, with club-like yellow anthers on the end, slowly uncurl, with the interior stamens dropping first. Notice how, at this point, the stamens and pistils are about the same length. As the flower continues to develop, that changes.

The flower in the next two pictures is further along than the last one, and you can see how nearly all the stamens have fully uncurled. The pistils have also lengthened, and their tips have opened up as they’ve become receptive to pollen.

An interesting pattern among many flowers is that their parts often occur in multiples. The columbine is a great example of that. It has 5 sepals, 5 petals, and 5 pistils. And when I took the time to count the stamens on one flower, there were 40 of them (which is a multiple of 5!). Another example of this is with Easter lilies, a flower you might be familiar with, and perhaps appropriate to mention as we approach Easter weekend. Easter lilies (as well as other lilies) have 3 sepals, 3 petals, 6 stamen, and 1 three-pronged pistil. Maybe this is a new tool for teaching the multiplication tables for those of you who are now homeschooling your kids?

When the columbine flower is finished blooming, the sepals, petals, and stamens fall off, leaving only the 5 pistils behind. They slowly turn upright and the ovaries at the base begin to swell. Eventually, they will open up like 5-sectioned cups, full of dark-colored seeds that bounce out when you brush up against the plants. But for now, the seeds are still developing.

Upturned pistils with swelling/ripening ovaries

As with the wood poppy, I gently opened one of the one of the ovaries to see the seeds developing inside.

As with the other species, I was again fascinated by the way the columbine has adapted its structures to an entirely different arrangement. Flowers are so cool!

Flower Parts Part 2: Our State Flower

Whereas, the Dogwood is a radiantly beautiful flower which grows abundantly in all parts of the State; and

Whereas, there is a great demand from all parts of the State that this Legislature adopt an official flower; Now, therefore,

The General Assembly of North Carolina do enact:

That the Dogwood be, and it is hereby, adopted as the official flower of the State of North Carolina.

In the General Assembly read three times and ratified, this the 15th day of March, 1941.

~H.B. 609, 1941

Most people are familiar with the flowering dogwood tree. Not only does it grow fairly abundantly in the wild, but it’s also frequently used in landscaping because of its beautiful white springtime blooms. It’s our state flower here in North Carolina, and also in Virginia (where it is both the state flower and the state tree). It’s the state tree in Missouri and the state memorial tree in New Jersey as well. While Virginia, Missouri, and New Jersey all specify that they’re referring to the flowering dogwood (Cornus florida), North Carolina does not. But reading the declaration by the General Assembly, I’m going to go out on a limb (pun intended) and assume they meant the flowering dogwood, too.

Though I’m a proud transplanted North Carolinian, I must say that I think Missouri and New Jersey did a better job when they selected the tree rather than the flower for their state symbol. Because this is our state flower:

picture of dogwood floret

Dogwood flower

Yup, that’s it. Not only is it kind of unremarkable, but it’s only about 1/4″ long. Unless you’re a nature nerd, you might have been expecting to see a picture like this:

dogwood blossom

Flowering dogwood blossom

Because I am a nature nerd, I have heard many times that the white “petals” on a dogwood are not really petals; they are actually bracts. Back to everyone’s favorite Plant Identification Terminolog: An Illustrated Guide by Harris and Harris, a bract is “a reduced leaf or leaflike structure at the base of a flower or inflorescence.” Hmmm… those don’t look like leaves to me! But if you take a closer look at the center of the bloom, and refer back to my previous post about parts of a flower, you begin to see why.

close up of center of dogwood blossom

As we get closer, you begin to see the details of the real dogwood flowers.

The dogwood does not have a simple flower. Instead, it has a cluster of tiny flowers (florets) in the center of the inflorescence.

closer look at dogwood flowers

An even closer look at the dogwood flowers.

You can see in this image how some of the flowers are open, and others (notably the three right in front) are not yet open. Given my recent fascination with the parts of a flower, I couldn’t resist dissecting this flower to look more closely at it!

cutaway side view of dogwood blossom

Cutaway of the dogwood blossom with 2 bracts and a few of the outer flower removed.

In the cross-section view, you can really begin to see the individual dogwood flowers. And on the flowers that I removed from the blossom, you can trace the development of the flowers as they open, and start noticing the flower parts.

four dogwood florets from unopened to fully opened

Development of dogwood flowers. In the first two flowers pictured, the petals have not yet opened.

The petals curve back as they open, revealing 4 stamens and a greenish pistil in the center. But as I mentioned in my earlier flower parts post, I really enjoy the challenge of finding the sepals…

close up of unopened dogwood flower

Super close-up of unopened dogwood flower

Getting even closer, you can see the downy green lip surrounding the unopened petals; I assume these are the sepals. I was very excited to notice this detail! (Yes, I am a nerd.)

super close up of dogwood flower, same picture as at start of post

Dogwood flower – the official state flower of North Carolina!

Here we are, back where we started: an open dogwood flower. Getting this close allows you to see the four pollen-producing stamen surrounding the pistil. It even looks like this flower has been pollinated as it appears there is some pollen on the stigma (though I’d say there’s a decent chance I accidentally pollinated it while manipulating the flowers).

So there you have it – North Carolina’s state flower!

Whether you want to or not… Parts of a Flower

When you take a flower in your hand and really look at it, it’s your world for the moment. I want to give that world to someone else. I want them to see it whether they want to or not.

~Georgia O’Keeffe

So far this spring, I’ve had to cancel workshops that I was planning for the North Carolina Museum of Natural Sciences taking educators to the swamp along the Roanoke River and to Great Smoky Mountains National Park. I’ve always been a huge proponent of sharing real experiences in the natural world with others, in large part because I learned the value of that so well from Mike. But in this challenging time when I’m no longer able to do that, I’ve decided to finally try to embrace the power of sharing things in a virtual way, while still encouraging people to get outside and experience the world around them. To that end, my colleague Megan and I have begun creating a series of online workshops for educators where we share some information through a video and then give them a couple nature journaling activities to guide their exploration of the nature in their backyards or local parks. My most recent endeavor in this series was to teach the parts of a flower and send folks out to apply that knowledge by observing flowers in their yard and recording what they notice. Looking closely into the world of flowers is fascinating, and particularly timely with the arrival of spring. So I wanted to share some snippets of what I’ve discovered with the Roads End Naturalist crowd!

Let’s start with a quick primer on flower parts. I spent time during a recent online meeting sketching one of the wild geranium flowers in our yard (ah, the wonders of turning off your video during a zoom meeting!) and created a diagram of the parts of a simple flower.

Sketch of wild geranium flower with sepals, petals, pistil, and stamens labeled.

Parts of a wild geranium flower, as well as enlarged drawings of a stamen and the pistil.

The main parts of a flower are the sepals, petals, stamens, and pistils. Let’s take a look at the arrangement of these parts in a simple flower that is abundant in our yard right now, the wood poppy, or Stylophorum diphyllum. This species is native to the eastern US, though technically not the Carolinas. However, it is native to the surrounding states of Virginia, Tennessee, and Georgia. I chose this flower as a starting point because it’s one of the larger flowers blooming in our yard right now, and it demonstrates most of the flower parts well.

Here’s the wood poppy flower. It’s about 1 1/2 inches in diameter and displays four vivid yellow petals. Petals are perhaps the most recognizable part of the flower. They are typically the most colorful part of the flower and often play a key role in attracting pollinators.

close up image of wood poppy flower

Wood poppy flower

But what about the sepals? According to Plant Identification Terminology: An Illustrated Glossary by James and Melinda Harris (yes, we own a copy of this book… what does that say about us?), a sepal is “a segment of the calyx.” So what’s a calyx, you ask? “The outer perianth whorl.” And a perianth is “the calyx and corolla of a flower, collectively.” I still don’t know what a calyx is… but corolla? “The collective name for all the petals of a flower.” Ah… botanical jargon. (Picture the eye-roll emoji here.) It just might be worse that geologic jargon. (In case you don’t know, I am NOT a botanist – my degrees are in geology, and I like to joke that you have to like big words, as well as hitting things with hammers, to be a geologist). At least I know what petals are (“an individual segment or member of the corolla, usually colored or white”)! The easiest way I’ve found to explain it is that the sepals are arranged outside of the whorl of petals. Sometimes they are green, other times they look a lot more like the petals. And I’ve noticed that they often seem to enclose the flower bud before it opens, which can be a helpful clue in identifying them.

So where are the sepals on the wood poppy? Normally, they would be underneath the flower, and might even be visible from the top-down view (some sepals act more like petals when the flower is open). But the wood poppy flower presented a mystery because underneath the petals is just the stem – no sepals! So does this flower lack sepals? To solve the mystery, I went looking around the yard to find some unopened flowers.

close up photo of a wood poppy flower bud with hairy sepals surrounding the yellow, unopened flower

Notice the two hairy sepals surrounding the unopened yellow flower.

In this picture of a flower bud, you can see two hairy, translucent sepals just beginning to open, exposing the yellow flower inside. I also looked around underneath the flowers and found a few sepals lying beneath the plant. So it turns out that for this species, the sepals fall off as the flower opens.

wood poppy flower form the side

I removed two petals and about half the stamens so that you can better see the structure of the wood poppy flower. Notice the lack of sepals underneath the petals.

So now we get to the important parts of the flower, the stamens and the pistil. Because why do we really have flowers, anyway? Not just to look beautiful in a vase on my kitchen counter. Flowers exist to produce new plants. Without flowers, there would be no fruits and seeds. Many flowers, like this one, rely on pollinators and put a lot of work into attracting them through vivid colors, nectar rewards, and sometimes even trickery (check out the part of this earlier post about the grass pink orchid). Other flowers rely on the wind to disperse their pollen (anyone else’s screen porch covered in pine pollen right now?), and some can self-pollinate. But back to the wood poppy, and most simple flowers…

Stamens are the male part of the flower that produce pollen. They are comprised of a stem-like filament and a pollen-producing anther. As the flower ripens, the anthers tend to shrink and shrivel as they produce pollen. An education student at East Carolina University once described a stamen as looking like an eye shadow applicator, and ever since then I’ve used that analogy, especially for ripe stamen that have granules of pollen (eye shadow?) on them.

riper wood poppy flower with brown antherns

This wood poppy flower has been open longer and is riper. The stamens are browned and shrunken, though a few at the center are still yellow.

In the center of the flower is the female part, the pistil. At its top is the pollen-receptive stigma. In some species, like the big star-gazer lilies that are often in grocery store bouquets, the stigma opens and has a sticky coating as the flower ripens, making it more likely that pollen grains will stick to it. Below the stigma is the thin style, connecting the stigma to the ovary, which is the swollen part at the base. When a grain of pollen reaches the stigma, it grows a pollen tube all the way down the style to the ovary, where it fertilizes an ovule (which I like to call a pre-seed).

ovary of a wood poppy

Wood poppy ovary that has begun to swell as it ripens. Notice the stigma and style still visible to the right side of the image.

Eventually, the wood poppy drops its petals and stamens, and the ovary begins to swell. Inside, the fertilized ovules are developing into seeds.

cross section of a wood poppy ovary showing white ovules inside

You can see the white ovules developing into seeds inside of this wood poppy ovary.

This ovary had swollen from about 1/4 inch long to about 1 inch long, and the ovules likewise had enlarged, making them much easier to see. In the closer, backlit photo below, the developing seeds are even more obvious, and you can notice how each one has a furry-looking edge on one side.

backlit close up of wood poppy ovary showing ovules

This backlit photo of the ovary shows the developing ovules in more detail.

Apparently, this species’ seeds are dispersed by ants and that furry bit is a fatty appendage called an elaiosome that ants like to eat. For more information on elaiosomes, check out a couple of Mike’s previous posts on seed dispersal by ants in bloodroot and trillium.

As I’ve refreshed my memory on flower parts, I’ve started looking at all the flowers in our yard with new eyes. Different species have developed fascinating takes on this basic structure. I’ll add more posts in the coming days highlighting some of the other flower species I’ve been examining. In the meantime, take advantage of this beautiful weather and head out into your yard with a magnifier and see if you can identify sepals, petals, stamens, and pistils on some of your flowers!

And if you’re an educator interested in the online workshops my team at the Museum has been creating, send me an email at melissa (dot) dowland (at) naturalsciences (dot) org.

Follow the Yellow Brick Road

“Follow, follow, follow, follow, follow the yellow brick road… We’re off to see the wizard, the wonderful Wizard of Oz… because, because, because, because, because, because of the wonderful things he does…”

~The Munchkins of Oz

In this particular case, the road is not so much yellow and brick as white and silky… but these little critters certainly do some wonderful things…

Eastern tent caterpillars on a cherry tree branch

Eastern tent caterpillars on a cherry tree branch

Hey, Roads End Naturalist readers, it’s Melissa here. With a little extra time on my hands I’ve been thinking a lot about ways to help teachers who are trying to teach virtually and parents who are now homeschooling to use the natural world as a teaching tool in this time of social distancing. So yesterday, I went out to document one of the most ubiquitous and friendly critters at this time of year – eastern tent caterpillars – as an idea for a subject to explore in your backyards or local parks (while staying 6′ from other people, please!).

Eastern tent caterpillars are the furry little guys who come out just as tree buds break in early spring and construct a silken web in the crotches of wild cherry tree branches. They’ve spent the winter as tiny larvae housed inside of an egg case that looks like a shiny, swollen growth on the tree branch. Our eastern tent caterpillars have been out and about for a little more than a week now, if memory serves me right. (Let’s see, I started to notice them in the branches before I stopped going to work, and that was a week ago Friday.) Most of them now are about 3/4″ long and starting to show some of the patterning that they’ll have later in life. And their tent homes range from about 4″ to 6″ across at this point.

Silken nest of tent caterpillars between two tree branches with one caterpillar on surface. Dark spots near bottom are frass.

Eastern tent caterpillar nest in between branches of a cherry tree with one caterpillar out on the surface. The dark spots inside the nest are frass (caterpillar poop).

Yesterday afternoon I got to observe a few of their really interesting behaviors when I went out for a look with the camera. I was very excited to note the silvery trails of silk running along most of the branches on the tree. As the young caterpillars go off to feed, and as they return, they leave a silken trail that is laced with chemical scents that guide the other caterpillars between the nest and leaves that they are feeding on. Over time, the silken “roads” become quite substantial. Apparently, a lot of research has been done on this behavior, and studies have shown that they are able to change the scent of the trail depending on the quality of food resources at its end – when a caterpillar comes back having fed successfully on a tasty branch, the next round of feeders will follow its trail back to the same spot.

I was even more excited when I saw a caterpillar follow a silk trail down one branch and back up another. Eventually, the caterpillar turned around and marched back to its nest – perhaps because at the end of the trial in the other direction was a different nest? It moved surprisingly quickly, so I had to anticipate its position along the branch to get a shot.

Picture of one tent caterpillar walking along a silken trail on a branch.

Tent caterpillar following a silken trail down a cherry tree branch.

A little later, after borrowing Mike’s fancy new camera with its twin light flash unit to try to better capture this phenomenon, I went out to a different, lower-down nest to try to get some closer images. The scene was totally different from earlier in the day! If you read this blog often, you probably know a little about caterpillars, as it’s a favorite topic in our household. But as a refresher, caterpillars shed their skin, usually five times (six for eastern tent caterpillars), to accommodate their dramatically increasing size as they grow. An analogy Mike once shared with me is that if a human baby grew as much as a caterpillar, it would end up the size of a blue whale! No one wants to live in a crowded house (especially when you’re not allowed to leave it… ah, pandemic humor…), so eastern tent caterpillars add additional layers of silk over time to increase the size of their nest.

tent caterpillar nest showing caterpillars inside

The caterpillars have multiple “stories” to their house and can move between the layers of silk. You can see caterpillars within different levels of the nest in this image, as well a few out on the surface.

And since they don’t have HVAC systems, they also use their nests for thermoregulation. One study I read said temperatures were typically 4 degrees C higher in the nest than outside of it (that 7.2 degrees F if you’re like me and need the conversion)! Of course, on a warm day like Friday, that might not be a good thing, and the caterpillars were congregated on the shady side of the nest when I went back out to see them. I’m not sure if this was because it was cooler, or if this was their typical nest-expansion aggregation behavior.

Image shows caterpillar nest with lots of caterpillars congregated on the shady side.

I’m not sure if these caterpillars were expanding the nest or thermoregulating by hanging out in the shade, or maybe both. But it sure was cool to see. They moved around a good bit while on the outside of the nest.

These caterpillars really are fascinating. Numerous references (like this one and this one as well as a favorite classic field guide, Observing Insect Lives by Donald Stokes) note that they typically have 3-4 periods of feeding during the day. Apparently, the pattern is that they aggregate outside the nest and add layers of silk to expand it, then go off and feed. Sure enough, a little later (once I’d solicited Mike’s help to bend the tree down so I could get a better look at the nest), lines of caterpillars were marching along their silken roads back from the outer tree branches, I assume after having fed on the tasty, tender cherry leaves. This was the coolest moment yet – seeing the little caterpillars nose to tail marching down the branch and back home!

a line of about 8 caterpillars walking down a branch nose to tail

These caterpillars were marching down the branch toward their nest. You can see the silken “road” if you look closely under their bodies. Take another look at the first image in this post for another example.

They all marched right into the nest to hang out until their next bout of feeding.

line of caterpillars on branch with white webbing of nest in right corner

One corner of the nest is at the right side of the image. The caterpillars entered through a hole where it meets the branch.

Here’s a few other interesting tidbits that I gleaned in researching this subject…

  • If there’s more than one nest in a tree, eventually the trails from caterpillars in each nest will run into each other. Apparently, the caterpillars will share nests. Friendly little guys!
  • Caterpillars in the same nest may be at different stages of development. It seems that development rate is linked to temperature, with warm temperatures being correlated with faster development.
  • Eating eastern tent caterpillars can cause abortion in horses! In 2001, more than 3000 mares aborted fetuses as a result of eastern tent caterpillar ingestion. My initial guess was that the concentration of cyanide, which is naturally found in cherry trees, by caterpillar feeding was perhaps the cause of the issue. However, it turns out that the hairs on the caterpillar are able to penetrate tissues inside the horse, and those hairs carry bacteria which, when they reach the uterus, can infect the horse and/or fetus and cause abortion. Fascinating!

So, here’s my challenge to you. Get out in nature (with proper social distancing), and see if you can observe some of these fascinating behaviors of eastern tent caterpillars!

If you’re looking for ideas for teaching kids at home, maybe challenge them to observe and document behavior over time. Here’s some questions and ideas to consider:

  • Can you document which times of day the caterpillars like to go out and feed? How does weather affect their behavior? What happens when they’ve eaten all the leaves on a branch?
  • Use a thermometer to measure the temperature on different sides of the nest – where is is warmer or cooler?
  • Use a compass to note the direction nests are facing – do they tend to be built at a certain orientation? Are the silk trails typically on a side of the tree facing in a particular direction, or is it more random than that?
  • How many caterpillars can you count in a single nest?
  • Using your observations, write a story or poem describing what it’s like to be a tent caterpillar, hanging out in a tiny silk nest with hundreds of your brothers and sisters… maybe not too dissimilar from your life right now? If anyone does this activity, feel free to post it as a comment on the blog – Mike and I would love to read some of your writing!
  • And if you really want to get into it, this book I found online has a whole bunch of experiment ideas using tent caterpillars – it’s chapter 17. I can’t find a way to link to the specific page, or even a page number to give you, but I found it by searching “eastern tent caterpillars” within the text.

I’d love to hear if any of the ideas are useful, or if you observe any interesting behaviors in your tent caterpillars. Please share in the comments on the blog or tag Mike and I on social media!

An Unexpected Love Song

“If you would win my heart, sing me a love song.”

~Jane Griner in the song “Sing Me to Heaven” by Daniel E. Gawthrop

Given the title of this blog, you might think it’s going to be about all the riotous birdsong that is happening out in our woods right now as temperatures warm and spring seems to be slinking up the south-facing slope across the road and into our north-facing yard. But that’s not the love song Mike and I heard last weekend when we took our hammocks out to the ravine behind our house (another south-facing slope).

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A perfect day for hammock-lounging

As I was laying in my hammock soaking up the sun like a lizard, I noticed a repetitive sound like two very short, quiet snare drum rolls followed by four to six slower beats that almost sounded like an extra-rapid secondhand on a clock. At first I thought it was just the straps of my hammock rubbing on the tree. But as I paid attention to the rhythm of the hammock’s movement, I realized the timing wasn’t right. I started looking around to try to pinpoint the source, and I noticed a wolf spider moving through the dry leaves on the forest floor. Amazingly, the sounds corresponded exactly to its movements – the snare drum rolls when it was paused, the tick-tock of the clock while it was moving. Whenever the breeze was still, I could hear it… first in one place, then another, and another. At one point, there were three wolf spiders moving around me, all making the same sound sequence. I’d heard that you’re never further than 4 feet from a spider – even while indoors – but it seemed more real as I realized just how many spiders there were surrounding my hammock!

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Wolf spider paused on leaves – click to enlarge

I watched the spiders for a long time trying to figure out just what was going on. Finally, two of them, one after the other, walked right below the edge of my hammock and I got a good view. Whenever they stopped and made the snare drum sound, they were moving their pedipalps (two front appendages, shorter than legs) up and down, vibrating on the dry leaves. It was incredibly fast, but when one of the spiders was close, I could actually see the movement. I was amazed! And as it walked through the leaves, I noticed it tapping its abdomen, which seemed to be producing the tick-tock sound. After that, I was hooked and probably spent more than an hour stalking these spiders with my iPhone, trying to capture their behavior.

I enhanced the volume on this video so that you can clearly hear the sounds the spider is making. I promise it’s the spider and not me shifting around in the leaf litter! But I still wasn’t satisfied that I understood what was going on… so I switched my phone over to slo-mo mode and tried to catch the movement of the spider again…

It’s subtle, and the sound is different because it’s slowed down, but you can definitely see the pedipalps moving as the faster rhythm is played. And you can hear the louder, more separated beats as it taps its abdomen.

Here’s another slow motion video. In this one, you can see how the presence of dry leaves amplifies the sound – when the spider is on the log, there isn’t much sound produced at all. But if you watch closely, you can still see its body vibrating as it makes the sound.

Knowing a little bit about spider mating rituals, I figured that the sounds I was hearing had something to do with that. In fact, just a week ago, on Valentine’s Day, I attended a talk on “spider love” put on the NC Office of Environmental Education. Dr. Eleanor Spicer Rice, author of Dr. Eleanor’s Book of Common Spiders, came to talk about the fascinating stories of spider mating. She was quite funny – her categories for male spiders interested in mating with a (almost always larger) female were: “how not to get eaten” and “well, let’s just make the most of it.” This is because it’s not uncommon for a male spider to be attacked and eaten by a female when he comes seeking something entirely different. For many orb-weaving spider species, the male will pluck the strands of the female’s web in a particular way to indicate that he is a potential mate and not just a fly that’s stuck in the web (aka, dinner). Other species like the green magnolia jumping spider will wave their legs around in something like a dance to show off for a female. A few species know it’s a lost cause and just go for it… and some even die in the act of copulation so as to leave their carcass attached to the female, effectively blocking access for other suitors. The world of spider courtship is dangerous!

Spider sex is fairly complicated as well. The female’s epigynum is located on the bottom of her abdomen, so rather than try to arrange himself upside-down underneath her, males go through a bit of preparation for mating. They produce sperm in their abdomen (from a gonopore about midway down on the bottom side, as you might expect), but they have to transfer it to the specialized “boxing glove” (cymbium) at the end of their pedipalps (via what’s called a sperm web) in order to mate. At least that way he has a chance to keep his many eyes on her chelicerae (jaws) while in the act.

So, back to my drum-playing spiders in the woods… a quick Google search turned up a bunch of articles about the so-called “purring wolf spider” or Gladiclosa gulosa. Apparently, wolf spiders are known for producing vibrations to attract a mate, and most early naturalists thought the sounds were caused by exactly the same thing I did – the spider tapping its pedipalps on a surface like a leaf. But in 1975 a researcher used high speed video to check this out in detail – and it turns out that spiders actually have what’s called a “stridulatory organ” on their pedipalps. Basically, this means that they are able to rub one part of their body against another to create a sound. Other insects are known to do this: the sounds made by grasshoppers and crickets are stridulations, and Mike included information about stridulation in horned passalus beetles in a previous post. But spiders don’t have ears… so it’s long been assumed that the vibrations are what is really important in communicating with a potential mate. However, researchers at the University of Cincinnati have been studying vibration- and sound-making in spiders, and for Gladicosa gulosa they discovered that not only does a female spider respond to the vibration produced by the male, she also responds to the sound (but males only respond to the vibrations).

Most of the studies that I could find describe spider behaviors when males are in the presence of females. And most of those on the sounds of wolf spiders focus on the snare drum rattle of the pedipalps and not the abdomen tapping. No one described the behavior we saw in the woods – namely, that a bunch of spiders were wandering around making sounds without another spider nearby.  I’m not sure what was going on, but my assumption is that they were literally trying to drum up a mate!

I’m also not sure what species Mike and I spent time observing in our woods, though I’m fairly certain it is a species of wolf spider (family Lycosidae). I’m not even entirely sure that they were males, because it’s hard to tell in my iPhone pics if the pedipalps have those distinctive “boxing gloves,” though their behavior makes me think they are males. After an exhaustive search of Bugguide.net and the 4 spider field guides in our house (yes, we have 4 spider field guides), I’m still not sure, though it’s possible these are Gladicosa gulosa – please let me know if you can identify them!

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Wolf spider – can you help ID? – click to enlarge

 

Whatever species they are, they exhibit an incredibly fascinating behavior, so if you’re a super nature nerd, it’s time to head out into the woods with a hammock on a warm, still spring day and listen for some spiders!

 

 

Longleaf Lost

The power of the ocean
in what does it lie?
In the endless, timeless roar of the surf?
In the immense vistas – the view to the end of the world?
In the glowing spray as it diffuses
the light of the rising sun?
In the power and mystery of its
dark depths?

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No matter—
it brings one to scale
it breathes into one serenity
it insists that one pause…

Once—
was the world filled with
such wild landscapes?
With these tests and salves for the
human spirit?
Before we spent what we did not own?

Were the monarchs of the southeastern forest
as the ocean?
The longleaf pines—
In their endless and timeless ranks
With their immense vistas—
views of waving grasses
as far as the eye could see?
In the power and mystery of their length and breadth?

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Would one have found scale? Serenity?
Would one have been impelled to pause?

Do we mourn for what we have not known
but by glimpses
through another lens?

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Grass, Bottlebrush, Candelabra, Pine?

Here’s to the land of the longleaf pine,
The summer land where the sun doth shine,
Where the weak grow strong and the strong grow great,
Here’s to “Down Home,” the Old North State.

~North Carolina State Toast

In my last post, I talked about some of the amazing, small plants that grow beneath the longleaf, but not so much about the longleaf itself. It, too, is well-adapted for poor, sandy soils and thrives in an environment frequently visited by fire, and has some amazing strategies for surviving under those conditions.

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Stand of longleaf in Croatan National Forest; the tall golden grasses are wiregrass which has seeded after a fire (click photos to enlarge).

Longleaf are not tolerant of shady conditions. In a mature savanna, they grow spaced fairly far apart so that each needle on each branch can receive as much sunlight as possible. They lose their lower limbs as they grow larger, and viewed from the ground seem to provide a loose, permeable canopy held aloft by elegantly arranged poles. This openness is one of the reasons that the savanna has such a diversity of low-growing species. The other is fire. Fire clears away other shrubs and trees, like turkey oak and gallberry, that typically grow beneath longleaf pine, and opens the forest floor for shorter species, like carnivorous plants, as well as seedling longleaf. Mature longleaf trees have thick bark that makes them resistant to all but the hottest fires. But with fire occurring every 3 years or so, historically, how would that allow new longleaf to sprout? Well, their growing stages are also perfectly adapted to this sandy, fire-prone habitat.

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Recently burned longleaf stand in Croatan National Forest

A longleaf seed is most likely to be successful if it germinates in a relatively open area where it receives a lot of sunlight… which is just what you would find in a longleaf savanna just after a fire. The seedling develops into a special phase of life, unique to longleaf, called a grass stage. At this stage, the “tree” is just a tuft of needles at ground level that looks very much like the surrounding wiregrass. For a period of around 3 years (sometimes shorter, but sometimes much longer), the longleaf grows downward rather than upward, sending a taproot deep into the soil to fuel future growth. During this stage, it is, perhaps surprisingly, fairly fire resistant. The thick needles protect the all-important growing tip at the heart of the grass stage. Even if the needles are mostly burned, the tree can still make it!

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Grass stage longleaf trying to blend in with the surrounding wiregrass

When the time is right, the longleaf moves out of the grass stage with rapid vertical growth. It develops a thick, white bud-like tip, sometimes called a candle, and from there begins its growth.

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The growing tip or “candle” of a longleaf

Its goal during this time is to get tall enough and develop thick enough bark to survive a fire. This is no time to worry about branches, so the young tree looks much more like a bottlebrush than anything else; this stage is often called the “bottlebrush stage.” Though an educator on a workshop once suggested that it should be named the “truffula stage” after the crazy-looking multi-colored trees in Dr. Seuss’ The Lorax. During this phase the young longleaf is most susceptible to fire.

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Bottlebrush longleaf striving to grow as tall as its neighbors

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Bottlebrush longleaf after a fire – notice that it is still green around the growing tip!

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A group of young longleaf burned in a recent fire. Many still have green needles visible in the center.

But a tree just can’t grow up, and eventually the longleaf begins to grow out as well. The graceful side branches reach out horizontally and then turn up toward the sky. The “candelabra” stage is well-named! Longleaf tend to grow their 8-18″ long needles in clusters near the ends of branches, adding to the visual appeal of the tree.

At about 25-30 years, longleaf reach maturity and start producing cones. Though the species is fire-adapted, it does not have serotinous cones – cones that open in the heat of fire. A neighbor to the longleaf, the pond pine, which commonly grows in boggy pocosins adjacent to longleaf savanna, does have serotinous cones. My coworker Megan decided we needed to observe this phenomena for ourselves; so, armed with a lighter and a closed pond pine cone, we did! With the heat from the lighter, the scales of the cone opened with an audible pop, kind of like the popping of popcorn. Inside each scale were two winged seeds, as with other pines. Pond pines also grow best after fire, so their serontinous cones are a great adaptation to promote growth when the conditions are right. Longleaf don’t use that strategy even though they depend on similar conditions for germination. But their cones are equally impressive. The largest pine cones in North Carolina, they can be up to about 12″ long!

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Pond pine cone, opened after a fire

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Longleaf cone with my size 9 (men’s 7) rubber boot for scale

The oldest documented longleaf in North Carolina is found in Weymouth Woods State Park and is more than 465 years old! Though perhaps at one time there were many such old monarchs of the forest, that’s rare now. But mature longleaf play a very important role in the ecosystem, particularly for red-cockaded woodpeckers. As longleaf age, they become more susceptible to red heart fungus, which softens the (very hard) heartwood of the tree. Red-cockaded woodpeckers are our only species of woodpecker that seek out live trees for nesting, and they prefer mature longleaf pine that are infected with red heart fungus. This is because they hollow out nest cavities in the living trees, and the softening due to red heart makes that easier. They also peck holes in the tree surrounding their cavity that draw out the tree’s sticky resin. This acts as a defense against a common predator, rat snakes. If you’re visiting a longleaf forest and spot trees painted with white rings, look up for the cavity! Biologists studying RCWs mark their nest trees in this way to make them more visible.

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RCW cavity – this one doesn’t have extensive resin wells drilled around it.

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The distinctive white band of an RCW cavity tree. I like to joke about the endangered woodpeckers who fly around with a paintbrush in their little feet to mark their homes so they can fine them again later…

The longleaf pine savanna is an amazing diverse habitat, and the longleaf pine is well-adapted to live there. If you have the chance to visit, see if you can spot each stage of its life – grass, bottlebrush, candelabra, and mature tree!

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Graceful, mature longleaf

The Most Wonderful Plant in the World

“This plant, commonly called Venus’ fly-trap, from the rapidity and force of its movements, is one of the most wonderful in the world” and “is one of the most beautifully adapted plants in the vegetable kingdom.”

~Charles Darwin

One of the tree species Mike didn’t include on his recent tree bark quiz, probably because it’s much less common in our area than the loblolly pine, is the longleaf pine. It has the thickest and most resinous bark of any of our pines, the longest needles, and the largest cones. But perhaps most interestingly, at least to me, is the ecosystem that grows up around it.

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Longleaf savanna in the Green Swamp Preserve

Longleaf forests once covered up to 60 million acres in the southeastern US, stretching from southern Virginia to eastern Texas. Early explorers and colonists saw dollar signs when they gazed upon the ‘endless’ forest: a source for all sorts of exportable products. The first major economic driver in North Carolina was the naval stores industry – the production of lumber, tar, pitch, and turpentine. Longleaf grow straight and true, making fantastic masts. Their resinous heartwood, called fatwood or lighterwood, was slowly burned under piles of earth, releasing pungent tar. Tar was boiled to thicken it into nearly-solid pitch. Tar and pitch were essential to the sea-worthiness of wooden ships: ropes and sails were soaked in tar, seams in the hull (and pretty much all other wood on a ship) were coated in pitch. The bark of living trees was scraped away, releasing the tree’s natural defense, resin, which was collected and distilled into turpentine. Turpentine had numerous uses, including as a remedy for colds (probably not the best idea). Though the longleaf forest must at first have seemed vast and limitless, after a century or more of harvesting, the once extensive blanket of longleaf pine in the southeast was reduced to about 3% of its original range.

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Cat-faced tree in Croatan National Forest; longleaf trees were cut in a distinctive “cat face” pattern to promote the production and allow the collection of resin for distilling into turpentine and rosin.

I’ve never been a huge fan of pines. When I lived in Durham, my house was surrounded by huge loblollies, and the yard was ALWAYS covered in pine needles. But a trip to a longleaf pine savanna can change that perspective fairly quickly. Longleaf are so successful in their habitats that they form what at first seems to be almost a monoculture – longleaf, and only longleaf, growing rank on rank as far as the eye can see. They are straight trunked with a waving crown – their lower branches drop off as the tree grows. But if you look a little closer at the dense ground cover, you’ll soon find that the longleaf pine forest is a surprisingly diverse ecosystem.

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Row upon row of longleaf, with a live oak standing out in the foreground. The oak is growing in a slightly wetter area at the edge of an ephemeral pool.

Some surveys of the ground cover in longleaf savannas have revealed more than 50 species of plants within one square meter. That is more diverse than a rainforest, at a small scale! And in North (and South) Carolina, we have some amazing species that live in that niche. Because of the nutrient poor soils found in longleaf habitats, plants need to have a good strategy for gathering the nutrients they need to thrive. Carnivorous plants have adapted some amazing ways to get nutrients from the ubiquitous insects that also live in this ecosystem. There are 4 primary groups of carnivorous plants in the savanna: sundews, butterworts, pitcher plants, and the most famous of all, the Venus fly trap.

When I saw my first fly trap, I must admit that I was a little disappointed. My high school put on “Little Shop of Horrors” when I was a student there, and Audrey was a pretty impressive, man-eating fly trap. In contrast, the traps of the real plants only get to be about 1 inch in diameter. But if you get down close to them and watch them in action, they are still impressive! The traps are actually modified leaves. They have green or red centers, the mid-rib of the leaf, each with 2-3 “trigger hairs” on the inside of the trap. The traps secrete sweet sap to lure their prey in and are rimmed with thin spines that will prevent escape. The spines look quite vicious, but are in fact more hair-like and won’t hurt you at all if you touch them. When an insect (or a pine needle yielded by a curious observer) touches two trigger hairs in quick succession, the leaf closes, trapping the insect. The repetition is important because the fly trap doesn’t want to be confused and close during every rainstorm! I hadn’t “tickled” a fly trap in a while, so on a recent trip to the savanna, I decided to try it out. Though I’ve done this before, I had forgotten just how quickly the leaf can close! Within less than 1 second it was shut. Apparently, this is one of the most rapid movements in the plant kingdom. Fly traps will reopen after a false trigger like mine, but it may take as much as a day for them to do that. And, they will only close so many times before turning black and dying, so it’s important not to “tickle” fly traps too often. But we typically encourage groups of teachers to try it, as it is an unparalleled educational opportunity to observe this amazing plant species. I filmed this video of a flytrap closing on a recent teacher workshop visit to a longleaf savanna.

Click here to see a video I took in the Green Swamp of a Venus fly trap closing!

Venus fly traps only grow within about a 100-mile radius of Wilmington, NC. Like longleaf, they depend on fire to keep their growing areas clear of taller species that will shade them out (more on fire later). They thrive in ecotones (areas of transition from one plant community to another) at the border between longleaf savanna and pocosins (shrubby bogs of the coastal plain). Because they are so interesting, and so rare, poaching has become a problem for fly traps. About two years ago, North Carolina increased the stakes for fly trap poachers – it is now a felony in NC.

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Venus Fly Trap

But fly traps aren’t the only show in town. Other types of carnivorous plants also thrive at the edges of the pine savanna, including pitcher plants, sundews, butterworts, and bladderworts. The insect-trapping strategy for each of these is different. Pitcher plants lure insects inside and then trap them in their tubular leaves which are slippery and lined with downward-pointing hairs. The insects can’t escape and the plant exudes digestive juices to claim its nutrients. Purples pitcher plants, Sarracenia purpurea, are a little different – they drown their prey in pools of water.

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The open leaves of the purple pitcher plant fill with water and drown insects… but inside of this one there was a small mosquito larva swimming around!

But even a pitcher plant can’t eat everything that falls in. Frogs sometimes hide out in them, a few species of caterpillar feed on the inner surface of the pitcher, and there’s even a species of wasp that lays its eggs in the shelter of the pitcher. Sundews look a bit like pin cushions that were left out overnight and have been coated by dew. The sweet-smelling droplets are both the lure for prey and the reason for its demise. It is entrapped in the sticky substance, and the leaf rolls up around it. The same sticky secretions also contain enzymes that digest the insect, providing the nutrients the plant is not getting from its environment.

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Notice the vivid, red sundews and the sandy soil in which they’re growing.

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We have 5 species of sundew in NC, 4 of which occur in eastern NC (the other prefers mountain bogs and a few sites in the Sandhills). I think this species is Drosera capillaris, but I’m not entirely sure without seeing a flower or seed.

Butterworts are a startling yellow-green color that stands out from the golds and browns of surrounding species in late winter/early spring. Their strategy for capturing prey is similar to sundews. They secrete a sticky substance on the surface of the leaf that lures, traps, ensnares, and digests small insects.

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There are 3 species of butterwort reported in NC. According to Radford’s maps of their ranges, I think this is Pinguicula caerulea.

The final group of carnivorous plants found in this type of habitat are bladderworts. Bladderworts are the most varied (species-wise) of our carnivorous plants – there are 14 or 15 species in NC! The bladderworts I have seen in the past are aquatic. Their underwater roots have bladders that suck prey in to be digested. Apparently, there are also terrestrial bladderworts that live in boggy peat soils or moist sand. I didn’t realize this before my trip, so I’ll have to search them out when I return!

Though fly traps have the most limited range of our carnivorous plants, each type is remarkable in its own way and well-worth seeking out in some of the remaining longleaf pine savannas. They’re easy to miss when not in flower, but if you scour the edges where pocosin meets savanna, you might be fortunate enough to find some!