Credit: John Nelson
The best time to see this plant is in the morning, just as the sun rises, while you quietly paddle in the backwater end of a pond or perhaps inside a mysterious Carolina bay. By the hundreds, the modest flowers, rising from their slender stalks, collectively resemble bright pink candle flames dancing over the dark water.
This is an aquatic, carnivorous plant, of course. It is just one of about 70 species and taxonomic varieties of "meat-eating" (or "insectivorous") plants in North America, spread across several genera. Worldwide, there are additional genera and species, but the majority are North American. Carnivorous plants became a focus of naturalists' attention with the publication of Charles Darwin's Insectivorous Plants in 1875, and our fascination with them has continued. Perhaps the most well-known local terrestrial carnivorous species include the bizarre Venus flytrap (Dionaea muscipula), which occurs naturally only in the Carolinas, as well as various pitcher plants (species of Sarracenia), which are broadly distributed in the Southeast.
Our mystery plant, however, is a fully aquatic species, most often found floating in the still waters of ditches, ponds, or blackwater creeks. It is not rare and is fairly common from eastern Canada to Wisconsin and south along the coastal plain into southern Florida. The elongated stems, often brownish or red, float just below the surface and are not rooted. Along their length, the stems bear rings of branches (there are no leaves). Each branch is divided into threadlike segments, many of which bear tiny, bladder-like structures that serve as traps. Minute invertebrates, including insects and their larvae, often end up inside these bladders after touching sensitive trigger hairs, causing the bladder to suddenly open and suck the victim inside. Nutrients from the trapped creatures are slowly absorbed by the plant’s tissues, providing a convenient way to acquire "fertilizer" in a watery environment.
Credit: John Nelson
The flowers, though, have nothing to do with trapping insects. They function in seed production. One or two (sometimes up to five) pink or purple flowers will bloom, attached to the stem by a slender stalk, emerging a few inches above the water. Each delicate blossom has a prominent upper and lower lip; after the blooming period, a small capsule forms. The seeds are tiny and covered in numerous pointy bumps.
Insectivorous plants, as a group, are one of the most fascinating subjects of biology, and with good reason. Beneath their beautiful, meek exteriors, killers lurk. (For more information, see Donald E. Schnell’s Insectivorous Plants of the United States and Canada, revised edition, published by Timber Press.)
John Nelson is the retired curator of the Herbarium at the University of South Carolina. As a public service, the Herbarium offers free plant identifications. For more information, call 803-777-8175 or email johnbnelson@sc.rr.com.
[Answer: "Purple bladderwort," Utricularia purpurea]
