This column was first published in 2014, but a walk around Beauchamp Point, Rockport, in early April features the skunk cabbage decked out in spring color. What is this wild cabbage?

It's April, but with temperatures in the mid-30s and a dearth of green growth, it feels and looks like late March. Morning walks though on Rockport's Beauchamp Point reveal telltale signs of spring. Wood frog and spotted salamander eggs appear in vernal pools, and phoebes and chickadees are singing.

Easily overlooked are the 6-inch green and maroon hood-like leaves of skunk cabbages pushing their way up through the last bits of snow. A dozen sluggish bees and flies buzz in and out of several skunk cabbage hoods. The hood is a highly specialized leaf called a spathe, which hides the spherical yellow flower head. The flower can only be seen by gently lifting the hood to peek inside.

Skunk cabbage is well named because it produces a very disagreeable odor, a clever pollination strategy to lure flying insects normally attracted to smelly carrion. Aside from the strong odor, skunk cabbages’ color and shape are strikingly handsome. Most spathes vary in color from pea green to maroon; a few are a striped combination of the two. No two cabbages are identical.

It's not happenstance or plant willpower that skunk cabbages are growing up through receding snow banks on frozen ground. Unlike other Maine plants, this wild cabbage has a unique ability to generate its own heat. Everywhere I look the snow has melted in a small circle around each skunk cabbage. For decades it was thought that the hole in the snow where cabbages grew was the result of the dark plant’s absorption of sunlight. The snowmelt around each plant is actually caused by thermogenesis, which is the production of heat normally associated with mammals and birds. Thermogenesis is rare in plants. In other words, skunk cabbage's vascular system behaves like that of a warm-blooded animal, at least for a few weeks in early spring. Its ability to generate heat enables the plant to grow and flower while snow still blankets the ground.

So what's the advantage for skunk cabbages to heat up? The answer lies in the age-old adage: "The early bird gets the worm." Or in the case of the skunk cabbage, by emerging first and blooming ahead of other plants, skunk cabbages garner the sole attention of early pollinators. As an additional reward to its pollinators, skunk cabbages provide heat inside their flower heads for flying insects during sub-freezing temperatures in March and April. The plant-insect relationship is mutually beneficial: the insects obtain nectar and warmth from the plant's flowers and the skunk cabbage has its pollen spread by flying insects. Life is good on Beauchamp Point's forest floor! This is even true of spiders that patiently wait to prey on insects seeking the plants’ pollen and warmth.

The plant’s cost-benefit ratio to produce heat is on the plus side of the ledger during a two-week period of enormous energy demand. Botanists have theorized that the metabolism of the skunk cabbage, while maintaining its “body” heat during freezing temperatures, is equivalent to the energy used by a chipmunk. In short, the skunk cabbage's springtime metabolism is more closely aligned to that of a warm-blooded mammal than a neighboring cedar tree. The staggering energy costs though is unsustainable and it's why skunk cabbages revert back to normal "cold-blooded" plant metabolism in May.

Leaning forward without falling into the wetland, I test the heat production theory of a skunk cabbage. With my finger inside the spathe, a small fly emerges from the flower head, surprising both of us. The flower warms my finger on a cold morning. The first botanists who inserted thermometers inside the plant's hood were astounded. The plant's body temperature was 36 degrees Fahrenheit above the outside air temperature. Subsequent checks day and night revealed that the temperature differential remained consistent during a two-week period in early April. During their growth spurt, skunk cabbage's thermogenesis is generated by growth of the flower heads as it uses oxygen to convert starch reserves in its roots into energy. The plant’s high starch content is known by generations of black bears. Sows with cubs feed on skunk cabbages shortly after emerging from their winter dens. The high caloric skunk cabbage accounts for 50 to 75 percent of the bear's early spring diet.

The Micmac Tribe in Maine used a dry powdered form of skunk cabbage root to treat diabetes and to aid in general metabolism. Historically, Maine's Penobscot Indian Nation used the plant's spring roots to rid children of parasitic worms. Science has also revealed that skunk cabbage is a diuretic. The medicinal qualities of skunk cabbage may help to explain why ingesting large quantities of the plant may play an important role in the bears' spring diet. Undoubtedly, skunk cabbage has not revealed all its secrets. But what it has revealed so far is nothing short of extraordinary. There's much more to skunk cabbage than first meets the eye.

PHOTOS COURTESY OF TONY OPPERSDORFF