The ghost in the forest.
Tryon Creek’s Strangest Plant
By Bruce Rottink, Volunteer Nature Guide and retired Research Forester
When you think “plants” you probably envision your favorite wildflower, your favorite shade tree, or maybe even your favorite vegetable! Different kinds of flowers, different shapes and sizes, but it’s almost a dead certainty that all of them are green, ‘cuz that’s what plants are, green! They contain a green pigment called chlorophyll that allows them to make their own food from sunlight, water and carbon dioxide.
Call me a weirdo, but my favorite plant is not green. It’s one of Tryon Creek State Natural Area’s most rare and unusual plants, Indianpipe (Monotropa uniflora).
In contrast to the normal, green Pacific waterleaf (Hydrophyllum tenuipes) plants in the picture below, the Indianpipe is white!
What’s going on with this plant? How does it make its food without the green chlorophyll?
Truth be told, Indianpipe, also known as ghost plant, is a slacker. It doesn’t make its own food! Scientists (who love big words) call it a “myco-heterotroph.” The “myco” refers to fungus, and the “heterotroph” means the Indianpipe gets its food from other organisms. Underground, something really interesting is going on. In order to survive, the roots of the Indianpipe need to connect with the underground mycelium (which look like long very thin hairs) of a fungus. AND, that fungus needs to have other mycelia attached to the roots of a tree. The fungus typically has a mycorrhizal relationship with the tree. That means that the fungus provides the tree with certain minerals the fungus has absorbed from the soil. In turn, the tree supplies sugars to the fungus.
Here’s where it gets tricky.
After the fungus has absorbed some sugar from the tree, the Indianpipe, which is also attached to the fungal mycelium, steals some of that sugar from the fungus. But in this case, the Indianpipe doesn’t provide any benefit to the fungus.
So some of the sugar produced by the hardworking tree is taken by the fungus, and then some of that sugar is stolen by the Indianpipe.
Right now is a great time to start looking for Indianpipes.
At Tryon Creek, I’ve seen Indianpipes emerging as early as May 29, but June and July seem to be the big months. At first you will just see a little white upside-down “U” shape emerging from the ground, as illustrated below. This one is only about 2 centimeters (3/4”) above ground.
In this example, the stem is on the right, and the flower head is on the left, in the upside-down, or “nodding” position. You can also see the tiny, nearly translucent leaves.
Hey, wait a minute!
If the Indianpipe doesn’t make its own sugar, it doesn’t need any sunlight. So why does it bother to pop up above ground every year?
Well, anytime an organism does something that doesn’t seem to make much sense, you can bet it has something to do with sex! And that’s the case here. The flower of the Indianpipe needs to get up above ground to shed its pollen and so that the female parts of the flower can be pollinated by other Indianpipes to produce seed for the next generation. Here some of the tiny leaves have already withered and turned black. The stem will continue to push up, and at first the flower will remain closed, as seen below.
As the stem grows, the Indianpipe plant gets taller, and taller. It tops out about 15 to 20 centimeters tall (about 6 to 8 inches).
The flower starts out life pointing down; as the stem grows taller, the flower gradually lifts up and points straight up to the sky.
And as the flower matures, you can see the anthers which produce the pollen. The pollen in the flower head is the only thing about the plant that has a normal color, yellow, although it is pretty pale!
After the pollination and seed production is complete, the soft stem soon starts to disintegrate, and falls to the forest floor. The cycle is complete, now cross your fingers for next year’s sighting of the ghost in the forest.
If you’re lucky enough to see one of Tryon Creek’s Indianpipe plants, please be respectful of these rare and delicate plants. Indianpipe, perhaps better than any other plant at Tryon Creek teaches us an important lesson; namely that there many different ways to be a success. It’s a lesson we can apply in our own lives too!