Skunked Again!

When I was a kid growing up in northern New Jersey, my friends and I often explored the wilds of the neighborhood. Many of the forests and fields where we found box turtles then are now suburban lots and corporate headquarters. My friend Rick and I would tromp through slick, muddy swamps and fens to hunt frogs and occasionally chase each other with the torn, foul smelling leaves of the Skunk Cabbage (Symplocarpus foetidus).

Leaves that smell like a skunk—an interesting strategy for a plant to keep from being eaten. Although I have heard that bears, when they emerge hungry from their dens, will eat the young leaves.

The leaves are not the only part of the plant with a scent. Weeks ago, I headed to nearby wetlands to see this “first wildflower of spring.” The red and yellow mottled hoods of the Skunk Cabbage, which are modified leaves called a spathe, had emerged through the snow and ice, looking like they melted the area around them. That’s actually what happens. Remarkably, as the plant uses starches stored within it in respiration it can heat itself up as much as 36 degrees above the air temperature!

Skunk Cabbage melting snow – Photo by Chris Norris

The flower cluster inside the spathe is the spadix, a rounded head of tightly packed flowers. This flower head also puts out that skunky smell, and the heated air spreads it around to attract carrion-feeding flies and gnats to encourage pollination. It’s amazing that there are flies out pollinating flowers in February and early March.

Skunk Cabbage – Photo by Chris Norris

Pollinators are really important. More than 90% of flowering plants need them to spread pollen from one flower to another to fertilize those flowers so that fruits can form. We often think of only bees and butterflies as pollinators, but in fact flies are the second most prolific pollinators behind bees.

Right now, the large, dark green leaves of the Skunk Cabbage are about at half their full size. When fully developed, the broad deep green leaves look like cabbage. They are spongy and full of water. When the trees above are fully leafed out, Skunk Cabbage leaves begin to fade. Because no woody material is left behind with this true spring ephemeral, by late summer you wouldn’t even know that Skunk Cabbage had been there.

Skunk Cabbage leaves Photo by Chris Norris

But their spreading roots are still below the ground. Those roots have pulled the stem downward. As the plant ages it grows deeper and deeper into the soil, waiting for late winter and early spring to begin the cycle all over again.

What’s that Quacking in the Woods?

Many of us have taken to the outdoors recently. I don’t have to tell you why. It’s a great way to get exercise and still maintain social distancing. So if you’ve been out walking, you might be asking yourself, “What’s all that quacking going on?”
No, Daffy is still safe in cartoonland and mallards are not quacking in the middle of woods. For one thing, it’s not their usual habitat.
You are hearing the mating call of the male Wood Frog, Rana sylvatica, a brown, dark-masked amphibian with a fascinating life history. In the early spring, sometimes as early as February, when the first “warm” rains come with a temperature above 44 degrees F (7 degrees C), wood frogs crawl out of the leaf litter and head for vernal (literally meaning spring) pools. These often temporary and usually shallow pools are found in forests in the Appalachians, New England, and most of Canada and Alaska. By using these temporary pools, the frogs avoid being eaten by fish.
These frogs have been semi-frozen in the leaf litter all winter. In the late fall when temperatures drop to freezing, special proteins cause the water in the frog’s blood to freeze first. This pulls out most of the water in its cells. While this is happening, its liver is pumping sugar (glucose) into the cells. This “anti-freeze” keeps the cells from freezing. Everything then shuts down—no beating heart or other functions!
This unique adaptation has enabled wood frogs to survive as far north as above the Arctic Circle. Scientists are studying this freeze-and-thaw cycle and hope what they learn can help with human organ transplants.
Back to the quacking. Check out the Wood Frog’s call and others on the Yale Peabody Museum Vertebrate Zoology Collection’s Online Guide to the Reptiles and Amphibians of Connecticut. After attracting a mate with its calls, the male Wood Frog externally fertilizes her eggs in the vernal pool. A female will lay an average of 1,750 eggs. Once the eggs have hatched, it’s a race for the tadpoles to develop into froglets and get out of the water before the vernal pool dries up in the heat of summer.

Click here to see the interesting findings that David Skelly, Peabody Director and Frank R. Oastler Professor of Ecology, and his graduate students have made in their study of wood frogs. Photo by Peter Paplanus from St. Louis, MO/ccby

Wood Frog by Peter Paplanus