Before winter leaves us, ​Watch this plant melt snow!

Generally, plants maintain temperature homeostasis by balancing the heat they gain with the heat they lose. In desert climates, for example, some plants have silvery or whitish leaves or hairs that reflect sunlight, keeping them cooler.  In colder climates, adaptations for retaining heat improve survival.  Arctic flowers use heliotropism (growing in the direction of the sun) and have bowl-shaped petals to trap light and warm air near their reproductive organs.  Some cold-climate plants even make antifreeze-like chemicals that prevent internal ice crystallization.

But Eastern Swamp Cabbage, a member of the family Araceae, actually makes its own heat!​

Heat helps spread its scent to attract pollinators

Eastern Swamp Cabbage (Symplocarpus foetidus) has a mottled maroon and yellow spathe (hood) and a spadix. A spathe is a modified leaf which looks like a hood.  The spathe surrounds the spadix, a cylindrical structure which contains the tiny flowers. The spathes of Eastern Swamp Cabbage are 4-6 inches long and are a mottled maroon and yellow; Spadices are 2-5 inches long and can be yellow or purple. The plants’ leaves are large, up to 22 inches long and 6 inches wide, and are arranged in a circle around a central stem, which does not grow higher than ground level.

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Eastern Swamp Cabbage stinks up early spring wetlands as it blooms in freezing weather.  Within the flowering spadix, only the mitochondria in the cells of female flowers (not in the spathe, leaves, or stems) are involved in heat production and management.    While flowering, the spadix maintains a temperature of 73°F, day and night, for more than a week. Air temperatures may fluctuate, but little change is seen at the spadix.  After the female flowers bloom, the plant cools, then it returns to ambient temperatures, and the male flowers release pollen. ​

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Unlike the Eastern Swamp Cabbage’s thermogenic and regulating mechanism, most other plants instead reward pollinators with calorie-packed nectar.  But Symplocarpus foetidus is believed to have evolved its near-current state during the Cretaceous period.  So, the system the species uses has been working for at least 66 million years.  And individual specimens within the species are so deeply anchored by their rhizomes that they can live for decades, or possibly even centuries.

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Cousins

With such a successful evolutionary strategy, its not surprising to learn that Symplocarpus foetidus has a cousin.   Western Swamp Cabbage, Lysichiton americanus, is also a member of the family Araceae.  

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The eastern and western varieties are cousins and have some commonalities.  They both grow in forested, watery environments.   Both flower for similar durations in the early spring.  They are both pollinated by flying insects, have large leaves, a spathe, and a spadix with tiny flowers.  And, of course, both Eastern and Western Swamp Cabbage stink!

​But these cousins are also quite different.  While the Eastern Swamp Cabbage has a purple and yellow overarching spathe, with a rounded purple spadix, the Western Swamp Cabbage has an open yellow spathe and a spadix that is elongated.  And, most importantly, Western Swamp Cabbages are not thermogenic.

Scaffolding into spring

This common, yet uncommon flower presents teachers with an opportunity to discuss varied scientific topics using a plant students may be quite familiar with because it can grow in the most wretched locations.  Students may see it roadside, on their morning drive or walk to school.  They may notice the greenery of its huge leaves among the previous year's dead foliage and marshy soil as winter comes to an end.

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Show your students a few photographs of Symplocarpus foetidus and they may know it, if only by sight.  But once they see that it is a plant that they can identify, and that they see in their envirnoment, it will become more intriguing.  

When students realize that they are familiar with this native, but unique, organism, you can make connections to homeostasis, pollination, evolution, or taxonomy.  To help with this, here is an activity about the Thermoregulation of Eastern Swamp Cabbage that is a great supplement to units dealing with regulation, plant reproduction, natural selection, or classification. It is an enrichment activity that would be appropriate to use during an ecology unit, or as a stand-alone lesson. 

​I have a "garden" of these pungent and exquisitely unusual wildflowers...these sultry snow melters of the vernal equinox.  Since most people don't think of flowers smelling putrid, I find those that do particularly facinating.  Maybe your students will, as well!  Especially Eastern Swamp Cabbage that is found all over my native state of New York.  Its beautiful huge green leaves are a welcome harbinger of spring that can chase away the frozen snow with its own internal "furnace".  Happy Spring Everyone!!

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