Wild Side: Many jacks in the woods this spring
One of the most distinctive of the spring ephemeral plants is the Jack-in-the Pulpit, “Arisaema triphyllum.” Growing up to two feet tall with one or two emerald green leaves each with three leaflets and a central “flower,” they are hard to miss. They are quite abundant this year.
What appears to be a strange green, brown, white and purple-striped flower is what botanists call a spathe; a leaf-like deep cup with an overhanging roof that forms the ‘pulpit’ over the ‘Jack,’ a spongy vertical cylinder called a spadix. The true flowers are small and clustered at the base of the spadix. The spathe and spadix resemble a minister standing in a pulpit preaching to the forest congregation.
This strange floral structure has evolved in members of the Arum family of herbaceous plants, most of which are tropical. The only other wild member of the Arum family in this area is the Skunk Cabbage that grows wet places.
Each Jack-in-the Pulpit plant has either male or female flowers. By opening up the overlapping front parts of the spadix you can see the cluster of small green berries on the female plants and thin brown anthers on the male plants. Most Jack-in-the-Pulpit plants with a single leaf are male and those with two leaves are female.
After the female plants are pollinated, the tiny berries grow into a cluster of bright red berries, each with one to three seeds. The pulpy berries are eaten by birds and the seeds are distributed widely.
The spadix aids in pollination by emitting chemicals that smell like fungus to certain species of flies that lay their eggs on fungus. The flies go into the spadix and do the pollinating.
Another cool thing about Jack-in-the-Pulpit is that they are thermogenic; they produce heat in the spadix attracts the pollinating flies. The related Skunk Cabbage produces heat by cellular respiration to melt its way through the icy mud in wetlands and to also attract pollinating insects.
As perennial plants growing from a corm, each plant forms leaf and flower buds in the fall and thus decides what sex it will be the following year. It may be that female plants that invest heavily in producing berries and have less nutrients stored in the corm, take it easy the next year as male plants.
Don’t eat them! They are poisonous! Jack-in-the Pulpit plants have evolved a potent deterrent to plant predators. They contain raphides in all their parts. Raphides are microscopic needle-like crystals of calcium oxylate. The raphides produce an intense burning sensation in humans, and are likely to tear and harm the soft tissues of the throat or esophagus of a predator chewing on the plant’s leaves.
When you are out in the woods early on a spring morning, enjoy the exquisite sound of the hermit thrush choir and listen closely for the sermon from the Jack-in-the Pulpit.
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--Dan Wilcox, outdoor columnist