10 March 2012

Skunk Cabbage, Symplocarpus foetidus, with newly opened basal rosette of leaves with spathe still present.

Time to get back to the garden begins in early March. One of our two new head gardeners, Anna Wallis, started with me this week, and together we have been cutting down the winter botany stubble, weeding out some of the winter annuals, and getting ready for a class next weekend. Sara Saurus, our other new head gardener, is still on her migration route north and aiming to join us next week. In addition to his daily stroll around the garden and woods, Jim Duke has been holed up in the grotto working on an update to the Peterson field Guide of Eastern/Central Medicinal Plants and Herbs, compiling information about Cuban plants, and nourishing Anna and me with soup.

Leucojum vernum

For the most part, this has been an extremely mild and spring-like winter. Here it is the first week of March with not a drop of snow to speak of except for the patches of snowdrops (Galanthus nivalis) in the valley. Rosemary certainly did not need her burlap bunting this winter and rejoiced with blossoms all season. The winter annual hairy bittercress (Cardamine hirsuta) along with crocus (Crocus chyrsanthus), dead nettle (Lamium purpureum), periwinkle (Vinca minor), and lenten rose (Helleborus niger) have dotted the terraces and woods with floral interest for weeks. Coltsfoot (Tussilago farfara) and butterbur (Petasites spp.) are currently in flower before their leaves appear. Spring snowflakes (Leucojum vernum), golden ragwort

Wood frog Rana sylvatica and gelatinous egg mass.

(Senecio aureus), spring beauties (Claytonia virginiana), and the invasive pilewort (Ranunculus ficaria) are blooming in the yin/yang valley. The red shouldered hawks are feisty, the wood frogs called early with their clicky quacks last week, the spring peepers have been out for over a week, phoebe is back screaming “phoebe” by the barn, the hunkered down nettles are beginning to rise, and the skunk cabbages that Jim transplanted down in the valley are already unfurling their leaves.

Eastern skunk cabbage with torn off spathe to expose spadix in bloom

Skunk Cabbage has been flowering in the bottomlands with stagnant water around the garden for the the last several weeks. One needs to go out to the woods where this native lives, squat down low to the ground, crush the leaves or the flowering parts, and get a mephitic whiff to understand first-hand why its name is so apropos. One needs to sink a bit into the soft, moist muddy earth to feel its habitat. One needs to be chilled by the cooler air in the ravines or the wet low-lying areas to know its haunt. One needs to rub the thick waxy surface of its hooded spathe and the bumpy globular spadix inside to examine its reproductive parts. Hmmm…that last sentence reads a bit kinky, but I am leaving it here for now. One can’t experience skunk cabbage sitting inside with a computer or hand-held device, one must get outside with hands-on and noses-on to experience skunk cabbage.

Skunk cabbage grows in moist bottomlands.

Eastern skunk cabbage (Symplocarpus foetidus – Family Araceae)  Etymology: symploke meaning connected; carpus meaning fruit; foetidus meaning fetid.  The Araceae family, otherwise know as Arums or Aroids, with 109 genera includes the Jack-in-the Pulpits and Green Dragons (Arisaema spp.), Anthuriums, Monsteras, and Philodendrons. Arums are distinct due to their spadix inflorescences and spathe leaf shaped bracts, as well as calcium oxalate crystals in their roots and other parts. Taste is acrid and bitter, and in large quantities toxic.

Skunk Cabbage is often the first native plant to bloom for the year and pokes it hooded spathe and tightly coiled leaves up and out of the ground sometime during mid-winter here in Maryland. Occasionally, I have been startled to notice them already up in late fall.  In the dead of winter, skunk cabbage comes alive. On most winters, I regularly find snow melted circularly around the emerging flowering parts and unfurled leaves.

skunk cabbage emerged in the snow - not taken 2011-12 winter

This winter, being so spring-like, lacked snow, and at first glance, the emerging plants were camouflaged and not immediately obvious where the skunk cabbage patches were. However, I know where to look since I have been traipsing the woods for decades, and these perennials live hundreds of years old in the same communities. I rarely see just one skunk cabbage and often encounter tens to thousands of plants. Skunk cabbage is thermogenic (heat generating), and according to Roger M. Knutson’s November 1974 paper in Science Magazine, Heat Production and Temperature Regulation in Eastern Skunk Cabbage, “[t]he spadix of Symplocarpus foetidus L. maintains an internal temperature 15° to 35°C (59 to 95° F) above ambient air temperatures of -15° to +15°C. For at least 14 days it consumes oxygen at a rate comparable to that of homeothermic animals of equivalent size.” I consider it a “warm blooded” plant in the winter – with the ability to regulate and adjust temperature to the outside temperature.  According to Knutson, to maintain skunk cabbage’s elevated heat generated during the winter is derived from the “actively respiring tissue of the spadix” as well as from the enormous root’s “inexhaustible supply of respiratory substrate.”

Peering inside the spathe is the spadix in bloom. This is cluster of individual petal-less flowers made of four cuboid sepals. Note the pollen grains from the four stamens surrounding the pistil of the ovary.

The temperature is maintained in the spadix and  Jim Duke writes in the Peterson Field Guide of Eastern/Central Medicinal Plants and Herbs that the heat is “because of the thermogenesis of salicylic acid and salicylates in the flower.” A more recent paper by R. S. Seymour challenges the salicylic hypothesis as it pertains to skunk cabbage. After discussing this discrepancy with Jim, it appears as if there is still research to be done on the exact mechanism of skunk cabbage thermogenesis and also on the constituents responsible for the odor.

Skunk cabbage hooded spathe family conceal their spadices inside.

Peering inside the mottled mauve and light green speckled and variegated spathe hood, one will see a dark mauve spadix – an inflorescence globe or ellipse of fused petal-less flowers. (see above photos) Each individual flower is cuboid shaped with four sepals. I have noted a variety of color schemes of varying shades of purple to mauve to green on the spathe.  While the spadix inflorescence is bloom, one can note in the center of each fused flower, a tuft of four stamens with bright yellow pollen. The warmth generated by the spadix coupled with the putrid smell of rotting meat attract insects such as honey bees, flesh flies, carrion flies, water lily leaf beetles and predator spiders (Eastman, J. The Book of Bog and Swamp, 1995). After the flowers complete their bloom period, the spathe withers and the leaves uncoil into rosette of large blades.  The brilliant green leaves of a skunk cabbage patch glow conspicuously in the woods by mid-spring and are indicators to me of where the ground is seeping wet and not so easy to walk. By mid summer, when the vernal rain ground water has evaporated and dried, the leaves disintegrate and dissolve leaving only the ripening ovary fruit as a trace. The leaves do not contain many fibers and are mostly water and air. I have read that the plant only propagates via the seeds from the fruit and not from root shoots and takes several years to mature to the point of producing flowering parts.

About this time last year, I took a  microscopy class and brought in skunk cabbage spadix, spathe, and early leaves to examine under the polarizing microscope. The projected image from my slide glowed with needles of calcium oxalate found in all parts of the plant. Calcium oxalate renders the plant difficult to swallow making it not the edible plant that one might assume from the vegetable in its name. Euell Gibbons in Stalking the Healthful Herbs (1966), tells of his horrific experience in following highly recommended recipes for skunk cabbage that claimed to leave “no trace” of the putrid odor. His tale explains that he used the “tightly rolled cones of young leaves” as suggested, and found not only was there a much more than trace of odor, but was aghast that his kitchen reeked with the smell of an “angry skunk.” He also was disheartened to learn that upon consuming just one bite of his dish, his mouth and throat burned with discomfort. He offered his dish to others, all of whom refused to take a second bite. Gibbons was tenacious to find a recipe, and even after the first inedible malodorous cooking episode, he tried to figure out how to use skunk cabbage as the “Indians” did.  He dehydrated the leaves and roots for months, and eventually, after many failed culinary attempts, discovered that with the dried plant material, he could cook skunk cabbage pancakes and Herb Meat Cabbage Pudding. Due to the toxic and burning calcium oxalates in fresh Skunk cabbage is not considered an emergency food and can only be successfully used when dried for an extended period. Bears, however, have been reported to eat the leaves after their hibernation and there are sightings of turkeys eating the flowers.

I personally do not find the smell as offensive as others have described. Upon sniffing several spathes and spadixes, I noted that not all of them reek, some are very mild, and others are fetid. I have not made foodstuff of skunk cabbage but have tried chewing on portions of the plant. After masticating even just a minute amount, the tip of my tongue burned for at over an hour.

Me digging skunk cabbage

Instead of cooking, I once turned to making a tincture of the roots. Years back, I was with in a class that dug the roots down by the Middle Patuxent River. The root was enormous and took several of us to finally get it out the ground. Apparently, skunk cabbage has wrinkled “contractile roots” that pull deep into the soil making the process of digging a root virtually impossible.

Ethnobotanist Daniel E. Moerman, reports that Native Americans used skunk cabbage for purposes such as coughs, pains, epilepsy, swellings, whooping cough, wounds, cramps, pains, headaches, and failing of the wound.  Skunk cabbage was listed in the US Pharmacopeia as Dracontium in the 19th century for use as as an antispasmodic, and for coughs, dropsy and epilepsy. The Eclectics used it as an emetic, for respiratory ailments, diaphoretic, spasmodic asthma, nervous irritability and in fever powders.  My yellowed and oxidized Back to Eden written by Jethro Kloss in 1939, tells of skunk cabbage’s use as a “sudorific (causing one to sweat), expectorant, pectoral, antispasmodic, stimulant [and an] expectorant.” Skunk cabbage is listed in his antispasmodic tincture for cramps in the bowels, snake bites and mad dog bites or even with lockjaw. Personally, I would not try it for rabies or lockjaw, but may follow his recipe for a respiratory expectorant or for cramps.  The late well-known herbalist Michael Moore used it in his formulas for cough, sudorific and catarrh powders and snuff. One must heed caution when using skunk cabbage and use it only in very low doses or with other herbs. It is also important not to confuse it with the similar looking and poisonous hellebore Veratrum viride, which grows in similar habitat.

Odd to think that a woman of rituals is one of the someones I have become. I find myself attracted to rituals that define the year and comfort my yearning to visit markers of time passing. Like others, I embrace rituals with family and friends by celebrating life cycle events and rites of passages. However, I must say that when left to my own, what I truly seek are the rituals of nature and seasonal phenological occurrences.  Skunk cabbage is a ritual for me. I feel empty without going to trusty skunk cabbage stands and seeking the spathe and the spadix when the days are short and nights are long. These days are growing longer now, the leaves elongating, soon the spathe will wither, and by autumn, the spadix will grow into a top heavy fruit flopped over hugging the earth. Sweet.

The time is now to get to the woods before the skunk cabbage flowers are passed.
Time to get back to the garden. Please come by and visit.

Skunk cabbage mature fruit.