Skunk cabbage flowers generate their own heat using an oxygen burning process very similar to that used by animals. The heat in these flowers can reach 70 degrees in the dead of winter, melting the snow around it and attracting beetles and other pollinators.
In Turkey Run Park, on the shores of the Potomac, Bill McLaughlin walks through a windy river's edge trail to a patch of soggy bog.
McLaughlin is the plant curator for the U.S. Botanical Garden and he's searching for an ancient, foul-smelling, primitive plant that existed back when the continents were still all in one piece: a skunk cabbage.
"They're very simple: big, green fleshy, they look like a giant hosta," he says.
In a few weeks, those vibrant leaves will get to be more than a foot across. They're so green they seem to glow. Bending down to get a closer look, it becomes clear where the name skunk cabbage comes from.
"Of course, I think you might be accidentally breaking a leaf there by kneeling and you might get a whiff of something unpleasant...I don't want to tell you what it's supposed to imitate but it does smell sufficiently like a skunk," McLaughlin says.
These beautifully stinky plants may be one of the longest-lived herbaceous plants in North America; they can grow to be hundreds of years old. But what is most remarkable about them, is their flowers. It's not just that they're pretty, which they are, they look sort of like twisted claw-shaped calla lilies.
"They're rich green and then just speckled very heavily with that really deep maroon, red, sort of mahogany color," he says.
It's what these flowers do that sets them apart.
"They were already probably popping out of the ground in January," McLaughlin says. "Yeah, skunk cabbage is really an exception and it has a secret weapon against the cold -- it's able to do what it does so early in the year because it makes heat."
Heat -- as in, if you look through an infrared camera, the flower is incandescent, blazing at 70 degrees, even in frigid January.
"Yeah it actually generates its own heat to volatilize the aromas -- and they're not pretty aromas -- that draw flies and carrion beetles as their pollinator," he says. "But it's making the heat even before the flower opens at all and it's doing it to push forward and break through ice and snow if need be."
McLaughlin says the heat will melt through the snow and ice.
"[If] you come down after a light icing or snow event in February, you'll see these big circles around the flower that's popping out of the ground," he says.
The plants do this by using an oxygen-burning metabolic pathway, just like some animals -- though different from vertebrates.
"It's basically respiring as much oxygen as an animal the same weight. And it does that by pulling all the reserves it has out of the ground, the carbohydrates, and burning them," he says.
It can even sense when it's warm out and doesn't need to heat up. The whole process is extremely energy intensive, but if you're going to attract pollinators in the dead of winter, you have to pull out all the stops. And it works -- inside the flower, beetles and flies feed and create winter love nests, and then spiders sometimes move in to feed on the insects. It's probably been this way for more than 100 million years.
"It's had a good formula, it's had a nice long run, and I'm sure it will still be here for many, many millions of years once we're gone," McLaughlin says.
For this season though, the skunk cabbage flowers are almost gone. In just a few days, the last of them will have dissolved away, back into the bogs where they sprouted from.