Skunk Cabbage: The sweet stench of spring

One of the earliest flowering spring wildflowers is also the stinkiest - Skunk Cabbage (Symplocarpus foetidus). My family and I make an annual trip in early spring to one of a couple of specific spots in the Credit Valley of Mississauga (write a comment below if you would like the specific location) to behold the beauty and the stench of this plant from the Arum family. We just made our trip this past Saturday (March 19) and many plants were in various stages of bloom. More on the smell shortly, but let me first describe this unusual plant a little more so you can recognize it when you come across it.

The spathe of the Skunk Cabbage

Skunk Cabbage is not your typical spring wildflower. Like all plants in the Arum family the most visible part of the "flower" is not actually the flower, but instead a hood-like structure called a spathe (the mottled dark red structure shown above) covering a cluster of flowers on a thick, fleshy structure called a spadix.

Part of the spathe removed to show the spadix (cluster of flowers)

These plants prefer wet seepy soils where the flowers emerge even when there is snow on the ground. They flower for 2-3 weeks and before the flowers senesce the leaves start to emerge as green pillars up out of the mud. By late spring the leaves unfurl to form large shield-shaped green umbrellas that last through the summer, typically in the shade of larger trees above.

Young Skunk Cabbage leaves in mid-spring (wikipedia.org). (cc) 

These plants have many fantastically unusual features. The most stunning is the smell. It isn't so strong to cause you to want to run from the forest for want of fresh air. In my case I really need to get my nose right in the flower to smell it. To me the flower smells slightly foul, like a dead squirrel left to rot for 1-2 weeks; incidentally, there was a dead squirrel near these plants, which didn't improve the aroma. My 7-year-old son described the flower's smell as vinegar; I'm not sure where he got that from. My 10 year-old daughter described it as being like lemon juice, whereas my wife said "skunky", which might be closest to the mark. 

Regardless, there is no question there is a stench, which leaves us with the question - What is with that smell? That smell is a complex blend of chemicals (ref 1, ref 2) believed to be the sweet perfume that attracts pollinators of the carrion-eating kind. That is right, flesh flies (Sarcophagidae) and carrion beetles (Silphidae) are attracted to the flowers. They are likely fooled by both the scent and the colour, thinking that they've found a dead animal ripe enough to provide the meal for their maggot babies. "Gross" you say? Well, that's nature and some of the most amazing biology of a wildflower that exists anywhere, although there are some other fantastical wildflower stories that I might tell another time if I come across them on the trail.

Before I finish this post I would be remiss if I didn't share with you one more amazing thing about this plant. The flowers generate heat - they are endothermic - a condition they share with mammals and birds. The spathe and spadix can be us much as 25C above ambient temperatures, making it possible for this plant to develop its flowers, facilitate pollination, and develop seeds and fruits even at sub-0C temperatures.

So next time you are outside, breath deeply and you might be lucky enough to smell the sweet stench of the Skunk Cabbage.