Touch Me If You Dare

In traditional Irish music, there is a tune that goes by the title “Touch Me If You Dare.” The same can be said for the Spotted Touch-Me-Not (Impatiens capensis). This plant gets its common name from its fruit, which when ripe pops and releases its seeds. It’s fun to get those mature, bulging fruits, called capsules, to “explode.” Hold the ripe capsule on both ends between your thumb and forefinger and press slightly inward. The five valves inside the fruit will coil back and eject the seeds up to 5 feet (1.5 meters) away! This is called explosive dehiscence or ballochory. Sometimes all you have to do is touch the fruit while walking by. It’s a good adaptation that gets seeds away from the parent plant and possibly to better soil.

The swelling fruit of Touch-Me-Not will pop out seeds if touched at both ends. Photo by Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons.

Spotted Touch-Me-Not’s species name, capensis, is a botanical mistake. The plant was named by Nicolaas Meerburgh, a botanist in the 1700s at the Hortus Botanicus in Leiden, Netherlands. He thought Spotted Touch-Me-Not came from the Cape of Good Hope in South Africa, and not North America.

Another common name for the plant is Jewelweed. There are several reasons for this name. The bright, showy, 1.25-inch (3.2-centimeter) trumpet-shaped orange flowers look like jewels one might wear as earrings. Or because beads of rain or dew on its leaves shine like jewels in the sun. Others say it is because microscopic hairs on the leaves (particularly the undersides) trap air and give them a silvery look when under water. Dip a leaf into water to see it shimmer and lift it back out. It will come out dry!

Jewelweed or Spotted Touch-Me-Not is a beautiful flower up close. Notice the curved spur at the back of the flower, which is full of nectar. Photo by USGS Bee Inventory and Monitoring Lab from Beltsville, Maryland, USA, Public domain, via Wikimedia Commons.

Yet another possibility for the name is the color of the seed. Peel the seed coat of a mature brown seed. Inside it is a bright, robin’s egg blue.

Because of the microscopic hairs on Jewelweed leaves, water beads up. Photo by Cephas, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons.

Jewelweed is an annual. It can really spread through your garden beds if you have rich, moist soil, but it is easy to pull. I leave lots of it in my yard at this time of year as its flowers are one of the primary nectar sources for the migrating Ruby-throated Hummingbird (Archilochus colubris). This year, with drought in our area, I am concerned about the birds getting enough nectar to refuel during migration since plants and flowers are drying up.

Ruby-throated hummingbirds seek out patches of Jewelweed during their migration south. The flower’s high sugar content (up to 60%) helps fuel their journey. Photo by Rhododendrites, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons.

Jewelweed might have a survival trick. Besides the showy, open chasmogamous flowers you usually see, which require cross-pollination, Jewelweed can also have small buds with unopened flowers on the same plant. These are self-pollinating, just like Violets (Viola spp.). These closed cleistogamous flowers can help the plant spread under stressful conditions, like drought.

The flower’s five petals and three sepals are fused. One of the sepals forms the small nectar spur at the back of the flower. This is usually twisted around in a curly-Q back toward the front of the flower. This twisted spur is thought to have played a role in plant–pollinator co-evolution. Hummingbirds are believed to be the most efficient pollinator for Jewelweed, although I have also seen bumble bees (Bombus spp.), and wasps pollinating Jewelweed.

Pale Jewelweed, or Pale Touch-Me-Not (Impatiens pallida), is a similar species of Touch-Me-Not that is more common in western New England. Like its cousin, it grows in moist areas, along streambanks and similar habitats. Pale Jewelweed’s nectar spur is bent downward at 90 degrees. This plant is pollinated mostly by bumble bees and other insects rather than hummers.

Pale Touch-Me-Not or Pale Jewelweed is another species found in the eastern United States. Notice the downward-pointing nectar spur. Photo by Andrew C, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0&gt;, via Wikimedia Commons.
 

Jewelweed has a long history of medicinal uses. Indigenous peoples made a topical salve with it. You may have heard that Jewelweed is an antidote for contact with Poison Ivy (Toxicodendron radicans). This has been argued for years. A controlled trial for the U.S. National Institutes of Health found the crushed stems and juice of Jewelweed were indeed effective for preventing the Poison Ivy rash after contact. The soapy compounds called saponins in Jewelweed might be why, yet washing with soap and water gave better results. But, if you are in the woods without access to soap and water, Jewelweed is a good solution.

Touch-Me-Not has evolved some fascinating adaptations to survive. Go ahead and dare to touch a seed pod today.

Published by Jim Sirch

Jim Sirch is the author of Beyond Your Back Door, a weekly blog about nature in your neighborhood. He is also Education Coordinator for the Yale Peabody Museum, a UConn Master Gardener and board member of his local land trust. As a trained naturalist, he brings a deep understanding of geology, plants and wildlife and how they interact within a particular ecosystem. He holds a B.S in Forestry from West Virginia University, a B.S. from Miami University in Science Education; and an M.S. in Environmental Studies Administration from Antioch University. He is also the 2014 Sigmund Abeles Award recipient from the Connecticut Science Teachers and Supervisors Association for outstanding science teaching and professional development.

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