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.

11 thoughts on “Whether you want to or not… Parts of a Flower

  1. Thanks for the education on flower parts, Melissa. I remember most of them from high school and college biology 50 some years ago. It was good to get the refresher, especially the part about missing sepals. I’ll be looking more closely at the parts of the flowers on my hikes. Im looking forward to your future posts.

  2. Pingback: Flower Parts Part 2: Our State Flower | Roads End Naturalist

  3. Pingback: Plant Parts Part 3: Wild Columbine | Roads End Naturalist

  4. Pingback: Flower Parts: The Iris’ Have It | Roads End Naturalist

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