Play with Your Pine Cones

I was walking under some pine trees near the Learning Campus and I took a picture of the cones I found.

PHOTO: The ground under the pine tree is covered in dry, brown pine needles and cones that are open, closed and in between.
I found two different kinds of cones on the ground under the pine tree.

When I was young, I noticed there were two different kinds of cones — some solid cones like the three in the lower left corner of the picture, and others are more like the open, branched cones at the top. I thought the pine tree made two different kinds of cones. Actually, they are different forms of the same kind of cone. I will show you how this happens.

I took three cones that were the same size and shape. Then I soaked one cone in a bowl of water. 

PHOTO: Pictured here are three pine cones of similar size, shape, and color.
I started with three pine cones of the same kind, shape, and size.

 

PHOTO: One pine cone is floating in a white bowl full of water while the other two are resting on the right side of the bowl.
I placed one cone in a bowl of water. It slowly began to change.

 

PHOTO: One pine cone is in the white bowl, now almost fully closed after ten minutes, while the other two are dry and unchanged at the side.
After about ten minutes, the wet pine cone is almost completely closed, while the dry cones are still open.

 

PHOTO: A wet, closed cone is shown next to a dry open cone.
Wet cones are closed, dry cones are open, and that is why cones from the same tree come in different shapes.

Then I let the wet and dry cones sit on my desk overnight. Guess what happened. Try it yourself to get the answer! Go outside and find a pine, spruce, or other conifer tree. Bring pine cones from those trees inside and watch them over time as they adjust to the warm, dry conditions in your home. Put one in bowl of water and see what happens. Let it dry and see if it changes again. 

What is going on here?

Pine, spruce, Douglas-fir and other conifers are so named because they produce cones that bear their seed. When conditions are favorable for the seeds to fall and grow, the cones open and release them. The seeds have the best chance to survive when the air is dry and windy, so they can blow to a nice fertile spot away from the shade of the mother tree. When conditions are wet and not so good for a traveling seed, the cones close to protect them.

Though the cones I found under the tree had released their seeds a long time ago, they still responded to the moisture levels of the ground and air. These cones were in between being damp from the rain over the weekend and drying in the sun.

Pine cone history

By the way, all conifers belong to a group of plants called gymnosperms. This means they produce “naked seeds” — seeds that are not contained within a fruit. Conifers do not grow flowers. Before there were dinosaurs on the planet, all plants reproduced by either spores or naked seeds. The seeds of some conifers can take up to three years to mature. Flowering plants (angiosperms) have a much more rapid reproductive cycle. Some angiosperms flower and produce mature seed in just one week. Understanding how cones and flowers have evolved is what Dr. Pat Herendeen is trying to figure out from plant fossils.


©2013 Chicago Botanic Garden and my.chicagobotanic.org

This Bark is Rough: Hackberry

PHOTO: A tall hackberry stands at the south entrance of a wooden bridge that crosses a seasonal stream in McDonald Woods. All the trees in the wood are leafless.

PHOTO: This shows a close up of the bumpy, scraggly bark of a hackberry tree.
Hackberry bark, south view

Now that most of the trees have dropped their leaves, the scenery appears brown and boring UNLESS you know what to look for. I’m talking about tree bark. Learning to identify trees by their bark can be a fun winter challenge.

For starters, I’d like to share one of my favorites: the hackberry, Celtis occidentalis. Hackberry may not be in the top ten trees you think of, but maybe it should be.

Take a look at the interesting texture of this bark. If you use your imagination, it’s like a miniature Grand Canyon on its side, with layers of material exposed on the edges of steep plateaus.

I find the texture on this north-facing side of the trunk to look like bicycle chains. What do you see?

PHOTO: The bark on the north side is also bumpy and scraggly, but the texture is more like a bike chain.
Hackberry bark, north side

Hackberry trees are related to elms and they grow all over North America. We have a few of them on the east side of Parking Lot 4. Scroll back up—do you recognize the large picture above? This was taken in McDonald Woods, along the trail near Parking Lot 4. The large tree to the left of the bridge is a hackberry.

One reason for the popularity of this tree is that the fruits—hackberries—feed birds, squirrels, and other woodland creatures. In the summer, caterpillars of mourning cloak, question mark, and hackberry emperor butterflies feed on the leaves. If you came to see Butterflies & Blooms in late summer, you may have seen the many mourning cloaks fluttering around the Learning Campus thanks to our hackberry trees.

PHOTO: Hackberry emperor butterfly shown with its characteristic pattern of black and white stripes against brownish orange background.
Hackberry emperor butterfly, shown with its characteristic pattern of black and white stripes against brownish orange background.

Open your eyes to tree bark this winter. You’ll find a range of interesting patterns and textures and maybe even learn something new about the trees around you.


©2012 Chicago Botanic Garden and my.chicagobotanic.org

What Are Those Bugs?!

PHOTO: Three boxelder bugs sunning themselves on the wood siding of the Garden's Learning Center.They’re all over the Learning Center and maybe around your house, too. They are boxelder bugs, and although they are a nuisance, they are harmless.

So while they are bugging us, let’s find some things to admire about them.

First let’s answer the question: Why are they all here right now?

It’s all about their life cycle. These insects spend their youth in the woods during summer, growing up flightless. In late summer/early fall, their wings develop and they can take flight, seeking a nice, cozy place to spend the winter. Can you blame them for wanting to come into our comfortable homes? OK, don’t answer that.

They belong to a group of insects commonly called “True Bugs.” Insects in this order are distinguished by their straw-like sucking mouth part, which they use to feed on the juices of plants. You see – they don’t have teeth, so they can’t bite you!PHOTO: this closeup of a boxelder bug has an arrow pointed to the red "V" on the bug's back where the forewings meet.

These insects also have two pairs of wings that cross in the back. The forewing is thicker than the bottom of the wing and this gives true bugs a distinctive “X” or inverted “V” on its back.

PHOTO: a close up view of a boxelder bug from the rear with its wings lifted to expose its brilliant red abdomen.

Now let’s talk about that beautiful red color! Watch one fly away and it will flash its sassy red abdomen. In nature, red coloring usually warns predators that this creature will taste bad. I was not able to confirm whether boxelder bugs taste bad or just mimic other bitter tasting bugs. Either way, I don’t recommend trying them yourself. And I must warn you that if you smash this bug on your wall or any fabric, that red color can stain.

While these insects are related to stink bugs, boxelder bugs do not have a bad odor. The bug I was holding in this photo must have been regretting this fact.

Wikipedia lists some other names for boxelder bugs, including “zug.” So when you see these creatures congregating on a sunny spot don’t say, “Ugh!” Say, “Zug!”

Enchanted Kale Forest

PHOTO: a variety of kale plants are growing in the raised beds of the Children's Growing Garden.

We’re all adjusting to the recent drop in temperature, but some plants actually thrive in cooler weather. Check out the redbor kale in the Grunsfeld Children’s Growing Garden. Forget bonsai, these kale varieties look like a miniature forest. Notice the branching leaf shapes are very similar to the trees in the background.

If you look at the kale from just the right angle, it appears to be part of woods that surround the garden.

PHOTO: The branching pattern of the kale leaves resemble miniature trees.See what I mean?

Kale is a member of a plant group called Brassica, which also includes broccoli, cauliflower, cabbage, and mustard. These plants grow well in the cooler months, and so they make excellent spring and fall crops. Since they come in a rich range of colors (dark greens to dusty teals to deep purples), and have an attractive variety of leaves (from smooth to lacy to ruffled), they are a favorite for fall garden displays.

Come to the Garden this month and take your picture near our enchanted kale forest!

Visit chicagobotanic.org/learningcampus/growinggarden for more information on the Grunsfeld Children’s Growing Garden.

Sunflowers in the Grunsfeld Children’s Growing Garden

Have you seen the sunflowers in the Grunsfeld Children’s Growing Garden this month? Let’s take a closer look to see what’s going on.

PHOTO: Sunflower nodding down toward the ground.

Many of the blossoms have lost their yellow petals and are bending down.
We need to take a closer look.

PHOTO: Very close up picture of a sunflower.

Just a little closer …

PHOTO: Extreeme close up of the middle of a sunflower, showing the tiny florets and sunflower seeds.

There!

Now you can see that one sunflower is actually made of hundreds of very small flowers. Notice the tiny, yellow, pointed petals of the individual flowers. Each blossom produces one seed. You can see the seeds where they have matured at the top edge of this sunflower. Can you find the spot where one seed is missing? Perhaps it fell out or was eaten by bird.

Sunflowers are what we call “composite” flowers, so named because they are composed of many florets growing so close together they appear to be one flower. If you look carefully at the arrangement of the flowers and seeds, you might notice a spiral pattern.

Other composite flowers you may know are daisies, dandelions, and mums. There are many composite flowers blooming at the Chicago Botanic Garden right now. Come for a visit to check it out, and bring your favorite magnifier so you can take a closer look at the real thing.

Visit chicagobotanic.org/learningcampus/growinggarden for more information on the Grunsfeld Children’s Growing Garden.