How can a plant grow if it isn’t green?

If you’re out in the woods this summer, you might notice some plants that aren’t green! How can this be? Plants are supposed to be green! At first you might that you’ve found a fungus, but with a closer look you may notice flowers! Fungi don’t have flowers, so we can rule them out. A few plants are white, yellow, or orange because they don’t have chlorophyll, the pigment that makes plants look green. Instead of harvesting energy from the sun, these plants get their nutrients either from other plants or from the fungal network in the soil, so we call them “parasitic” plants.

Two parasitic plants you might find in the parks this summer are bear corn and common dodder. You might also find Indian pipe (I don’t have any pictures of it yet, but if I find some I’ll post them).

Bear Corn. Also called squaw-root or cancer root (Conopholis americana), this plant grows in woodlands. The only known host of bear corn is oak, so if you find bear corn there must be an oak somewhere in the area. Bear corn looks like a pine cone or a corn cob sticking up out of the leaves.

Squaw-root (Conopholis americana)
Bear corn, also known as squaw-root or cancer root (Conopholis americana).

Common Dodder. If you’re wandering around an open field or wetland, you might stumble upon a mass or orange threads sprawled all over the plants. This parasitic plant is called dodder. We have 9 dodder (Cuscuta) species in Michigan. Our most common species is called common dodder or swamp dodder (Cuscuta gronovii). It can grow on many different hosts. Our species of dodder are annual plants, which means that they only grow one year. The seedlings sprout in the spring, and if they do not find a suitable host they die. If they do find a host, they grow special roots (haustoria) that tap into the host to suck out water and nutrients. You’ll find the little white dodder flowers in July and August.

IMGP3407
The dodder in this picture is the orange threads twined around a goldenrod. If you look closely, you’ll see the little white flowers on the orange stems. The dodder gets all of its water and nutrients from the host plant.
IMGP3365
This dodder is growing on Joe-Pye Weed, a common wetland plant. The little clusters are the flowers that are still in bud, getting ready to open.
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About Ben VanderWeide

I am the Natural Areas Stewardship Manager for Oakland Township Parks and Recreation in southeast Michigan. I have a doctorate in biology (focused on plant ecology) and I am passionate about protecting and managing natural areas.

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