Mystery plant comes with a bite
The best time to see this plant is in the morning, just as the sun is coming up, while you quietly paddle in the backwater end of a pond or perhaps inside a mysterious Carolina bay. By the hundreds, the modest flowers, arising from their slender stalks, appear collectively like bright pink candle flames dancing over the dark water.
This is an aquatic, carnivorous plant. It is just one of about 70 species and taxonomic varieties of “meat-eating” (or “insectivorous”) species in North America, these placed variously in several different genera. Worldwide, there are additional genera (and species), but the great majority are North American. Carnivorous plants really became a focus of naturalists’ attention with the publication of Charles Darwin’s book “Insectivorous Plants” in 1875, and our attraction to them has continued. Perhaps the most well-known of our local terrestrial carnivorous species include the bizarre Venus flytrap (Dionaea muscipula), as well as various pitcher plants (species of Sarracenia).
Our Mystery Plant, however, is a completely aquatic species, most often found floating in the quiet water of ditches, ponds or blackwater creeks. It is not rare and is in fact fairly common from eastern Canada to Wisconsin and south along the coastal plain well into southern Florida. The elongated stems, often brownish or even red, are elongated and floating just below the surface, not rooted. Along their length, the stems bear rings of branches; there aren’t any leaves. Each branch is much divided into threadlike segments, many of which bear tiny, swollen, bladderlike structures which serve as traps. Minute invertebrates, including insects (and their larvae), will often end up inside these bladders, upon touching sensitive trigger hairs, which causes the bladder to suddenly open, sucking the victim inside. Nutrients from the trapped critter are slowly absorbed by the tissues of the plant, so a convenient way of acquiring “fertilizer” in a watery environment is afforded.
The flowers, though, don’t have anything to do with trapping insects; they function in seed production. One or two (sometimes up to five) pink (or sometimes purple) flowers will open, 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; following the blooming period, a small capsule is formed. The seeds are quite tiny, and they each bear a number of pointy bumps on the surface.
John Nelson is the curator of the A.C. Moore Herbarium in the Department of Biological Sciences at USC.
(Answer: “Purple bladderwort,” Utricularia purpurea)