This week, I’m featuring Skunk Cabbage (Symplocarpus foetidus) as one of our local wildflowers that begins to bloom at this time.
Skunk Cabbage is the first native wildflower to bloom each spring.
Skunk Cabbage generates warmth by breaking down starch that it has stored over the winter in its roots and rhizome, or underground stem. This process is called thermogenesis.
The plant can keep its internal temperature fairly constant at about 60 to 70 degrees Fahrenheit for a week or two in early spring, even when the outside temperature is near freezing. Once this crucial two-week period is over, it stops generating heat.
That’s a rather simplified explanation of what happens. For a much more detailed explanation, featuring chemistry and mathematical equations, please feel free to read The biochemical basis for thermoregulation in heat-producing flowers.
-Thermoregulation in skunk cabbage (S. renifolius). (A) Skunk cabbages were photographed using a camera in the visible (left panel) and infrared spectra (right panel). The thermal image was taken with Thermotracer SC620 (FLIR). Heat production was observed in the spadix during the female stage of floral development. (B) The sequential changes in spadix (red) and air (blue) temperatures during floral development from the female to the male stage. Spadices at the female stage can maintain internal temperature at approximately 22-26°C, whereas spadices at the male stage cannot produce heat. Spadices at the bisexual stage between the female and male stages show unstable thermogenesis . Photographs of a female-and a male-stage spadix, are shown in the upper right and lower right panels, respectively . (B) was partially extracted from figure 1 in our previous paper (Ito-Inaba et al., 2009 a).
Source: Yasuko Ito-Inaba. Thermogenesis in skunk cabbage (Symplocarpus renifolius): New insights from the ultrastructure and gene expression profiles. Advances in Horticultural Science 28(2):73-78. August 2014.
It is the only plant in our region that has this capacity.
Identification Tips:
At the center of the plant there is a short, round central root mass (a rhizome) out of which the leaves arise and from which the extensive root system forms. The roots are each about a quarter of inch in diameter and extend out from the rhizome mass in large numbers and in all directions. They grow unbranched for several feet and then terminate in an extensive system of fibrous rootlets. They solidly anchor the plant into the often loose, mucky soil. The roots have circular surface ridges which grab onto the soil and via root contractions actually help to pull the growing plant deeper and deeper into the soil. Older plants, then, are rooted more deeply than younger plants. This contractile root adaptation may also help to prevent frost heaving of the plant out of the freezing and thawing wet soil in which it resides. The root system has been described as being virtually indestructible and may persist for decades and, possibly, even hundreds of years. The roots are also important storage sites for the accumulated polysaccharides resulting from photosynthesis. These energy molecules are used by the plant each year for its flowering and growth and also for the production of heat as described above.
This perennial plant produces a rosette of basal leaves during the spring; these leaves reach their maximum size by early summer, and they wither away by the end of summer. The blades of these leaves are up to two feet long and one foot across; they are medium to dark green, oval, smooth along the margins, and hairless. The leaf blades have prominent veins, especially on their lower surfaces.
The inflorescence consists of a spadix that is surrounded by a curved spathe (which is a modified leaf); they are located near the ground. The curved spathe is about 4-6″ long and half as much across; it tapers to a point at its apex. The convex outer surface of the spathe is brownish-purple and often streaked with yellow and red, or spots of purple and green; this surface is smooth and hairless. On one side, the spathe remains open to reveal an ovoid spadix about 2″ long. This spadix is covered in all directions with small flowers, each about ¼” across. Depending on the local ecotype, the spadix can be pale yellow to dark purple.
Thermogenic plants are also protogynous, meaning that the female part of the plant matures before the male part of the same plant. This reduces inbreeding considerably, as such a plant can be fertilized only by pollen from a different plant. This is why thermogenic plants release pungent carrion-like odors; to attract pollinating insects. The bruised foliage of this plant can produce a similar odor. The spathe soon withers away, while the spadix becomes enlarged into a compound fruit with a blocky surface. This globelike compound fruit becomes about 4″ tall and 3″ across; it is initially green and dark purple, but later becomes dark brown or black as it disintegrates.
Folklore:
Skunk Cabbage is considered a magical herb. When wrapped in a bay leaf on a Sunday, it is believed to form a talisman that draws good fortune to the bearer.
Culinary and Medicinal Uses:
Ingesting the plant can cause mouth pain and irritation due to the presence of oxalates. While some sources indicate that young, cooked leaves (or those thoroughly dried) can be safe to eat, it is probably best to simply avoid ingesting any part of this plant. Overconsumption, particularly if raw, can lead to kidney failure and even death.
Skunk Cabbage was much used by North American Indians primarily for its expectorant and antispasmodic properties to treat bronchitis and asthmatic conditions, a use that is still employed in modern herbalism. In the 19th century (from 1820 to 1880), the United States Pharmacopoeia listed Skunk Cabbage as the drug “dracontium.” It was used in the treatment of respiratory diseases, nervous disorders, rheumatism and edema. (NOTE: The original 1753 classification for this plant by Carl Linnaeus was Dracontium foetidum. Known as the “father of modern taxonomy,” he was the Swedish botanist, zoologist, and physician who formalized binomial nomenclature as the modern system of naming organisms.)
Externally, it has been used as a poultice to draw splinters and thorns, to heal wounds and to treat headaches. The root hairs or rootlets have been applied to dental cavities to treat toothache. A tea made from the root hairs has been used externally to stop bleeding. An inhalation of the crushed leaves has been used in the treatment of headaches. The leaf bases have been applied as a wet dressing to bruises.
Wildlife Value:
The flowers are pollinated by flesh flies, carrion flies, and various gnats. These insects are attracted by the carrion-like appearance of the inflorescence and its unpleasant odor, which is enhanced by the increased temperature that is maintained within the spathe during early spring. Caterpillars of Ruby Tiger Moth (Phragmatobia fuliginosa) feed on the foliage of this plant, but it is not exclusive to feeding on Skunk Cabbage.
The foliage is toxic and inedible to most animals because it contains crystals of calcium oxalate. However, after they emerge from hibernation during the spring, hungry American Black Bears (Ursa americana) and Snapping Turtles (Chelydra serpentina) occasionally eat the foliage, when little else is available. White-tailed Deer (Odocoileus virginianus) will eat the flowers in early spring, often consuming the spathe to gain access to the more nutritious spadix. Canada Geese (Branta canadensis) and Wood Ducks (Aix sponsa) eat the seeds.
Where Found Locally:
Curious By Nature 