Stinky skunk cabbage is actually a sign of spring

If your daily commute takes you along a stream that meanders through a wet meadow, watch for early signs of life as spring approaches.

Skunk cabbage

Even as snow or ice still covers the ground, skunk cabbage begins to grow.

I first noticed skunk cabbage while riding the school bus many years ago.

Every day we passed a small wetland, and about this time of year, I observed curious plants emerging through the snow. My dad congratulated me for recognizing skunk cabbage.

At first, a sharp greenish spike pierces the ground and snow. On successive sunny days, the spikes grow rapidly and take on mottled splashes of maroon and/or yellow.

The spathe

The spike grows in a spiral pattern and forms a protective hood. Botanists call the hood, a highly modified leaf, the spathe.

Inside the protective cover of the spathe grows a head of small nondescript flowers called the spadix.

To see the flowers requires close examination of the entrance to the spathe. You’ll probably need to get on the ground to peek inside the spathe.

As the spathe and spadix grow, they generate enough heat to actually melt snow and ice surrounding the plant.

Rapidly growing skunk cabbage flowers can maintain a “body temperature” as much as 30 degrees Fahrenheit higher than ambient temperatures.

The heat is generated via oxidation by the growing flowers. This requires an unusually high rate of oxygen consumption for a plant. In fact, it’s comparable to the metabolic rate of a hummingbird.

Purpose of the heat

The purpose of the heat is two-fold. It produces the chemical odors that mimic decaying flesh and attract insect pollinators.

The plant’s body heat also warms the air within the flower and this rising current carries with it the pungent odor of the plant.

Think of it as a min-thermal, similar to those that carry soaring hawks and vultures, only this one just carries aromatic molecules.

Watch for a variety of tiny pollinating bees, flies and beetles attracted by the odor as they visit skunk cabbage on mild late winter days.

Odor

Walk among a patch of flowering skunk cabbage and you’ll notice a faint skunk-like odor. Put your nose to the opening of the spathe and the odor becomes easily recognizable.

After the flowers are pollinated, skunk cabbage fruits begin to form. The flower head swells and forms spherical balls about two inches in diameter.

The heads consist of maroon colored fruits, each containing a single seed.

By late summer, the fruit’s flesh decays, and the seeds return to the soil to await germination.

Jack-in-the-pulpit

Jack-in-the-pulpit, also a member of the arum family, exhibits a similar growth form, but it doesn’t emerge on forest floors until late April.

Jack, the spadix, grows inside the protection of the canopied pulpit, the spathe. It grows profusely in rich bottomland soils along wooded waterways.

Skunk cabbage’s large conspicuous leaves form well after the flowers emerge.

Toward the end of April, as the skunk cabbage spathe begins to wilt, a bud next to it begins to grow rapidly and unfurl.

Bright green leaves unfold and suddenly skunk cabbage becomes a much more conspicuous wetland plant.

Wetland habitat

In fact, its roots require year-round moisture, so it is a plant that defines wetland habitat.

When I was a kid, I trapped muskrats where the skunk cabbage grew. Their runs and burrows typically riddled the area.

Skunk cabbage leaves can grow to more than 24 inches in length, so it’s hard to miss them. And when crushed, the leaves emit a distinctive skunk-like odor.

By mid-June, the enormous leaves begin to decay. Left behind at the base of the decaying spathe and leaf stalks are the round maroon-colored fruits, each protecting a single seed — the source of the next generation of skunk cabbage.

Of course, not all the seeds successfully germinate. A variety of game birds including wood ducks, ruffed grouse and ring-necked pheasants eat the seeds. But even some of those pass through the birds’ digestive tracts and ultimately germinate.

About the Author

Scott Shalaway, who holds a Ph.D. in wildlife ecology from Michigan State University, writes from his home in rural West Virginia. A former faculty member at Oklahoma State University and the University of Oklahoma Biological Station, he has been writing a weekly nature column for newspapers and freelancing for magazines since 1986. Send questions and comments to scottshalaway@gmail.com. You can also visit his Web site, http://scottshalaway.googlepages.com. More Stories by Scott Shalaway

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