Carnivorous plants are species of plants that attain at least some if not all of their nutrients by trapping and consuming animals. They are something of a pop-culture icon, being featured in poetry, paintings, short stories, video games, and even on the big screen in roles ranging from "The Devil's Snare" in the Harry Potter series to "Audrey II" in Little Shop of Horrors (Schaefer, 2021). There are around 600 described species of carnivorous plants in 17 genera (Jennings & Rohr, 2011), and they can be found in nutrient-poor soils on every continent on Earth except Antartica (Natural History Museum, London), capturing their prey through snap traps, pitfalls, adhesive traps, and various other methods across the globe!
Carnivorous plants provide important ecosystem services by capturing and consuming large amounts of mosquitos, midges, deerflies, and other small creatures that can transmit disease. Some carnivorous plants even form ecosystems themselves, providing habitat for entire communities of specialists (Jennings & Rohr, 2011).
However, of the 102 carnivorous plant species that have been evaluated by the International Union for the Conservation of Nature (IUCN), more than half (57) of them are listed as threatened. Some of the biggest threats carnivorous plants face today include the loss of habitat from agriculture, drainage, fire suppression, and deforestation, as well as the deleterious effects of pollution, over-collection, and invasive species (Jennings & Rohr, 2011).
Their unique ecological function, as well as their vulnerability to habitat loss and competition, make carnivorous plants an especially important group to focus conservation efforts towards. In Illinois, we have several native carnivorous plant species that are threatened or endangered in the state; to protect these species, we need to have an understanding of where they are and how their populations are faring.
Through Plants of Concern, we've collected data for 7 Species of rare carnivorous plants at 22 Sites across 48 Subpopulations with 325 Monitoring Reports!
Keep reading to learn more about just some of the state-listed carnivorous species that Plants of Concern monitors in Illinois!
The Bladderworts (Utricularia spp.)
Utricularia cornuta (Horned Bladderwort). Photo by Carol Freeman.
The genus Utricularia is characterized by the small carnivorous sacs, or "bladders," that are produced along its stem. The bladders are hollow underwater structures with a valve that is kept closed by generating a state of low pressure within the traps. When a small creature triggers the bristles that project from the surface of the door, the trap suddenly opens, sucks the prey inside, and closes again for digestion, all within the span of 1/35th of a second. The trap can be reset and ready for action in as little as 15 to 30 minutes! (Petruzzello, 2025)
Members of the Utricularia genus often consume mosquito eggs and larvae, even predating on parasitic flatworms known as "Blood Flukes" (Schistosoma spp.), making Utricularia importance for diminishing the risk of human disease. (Jennings & Rohr, 2011)
Here are the Four Bladderworts Monitored by Plants of Concern:
Utricularia cornuta (Horned Bladderwort; Illinois Endangered)
Utricularia intermedia (Flat-leaved Bladderwort; Illinois Threatened)
Utricularia minor (Small Bladderwort; Illinois Endangered)
Utricularia subulata (Zigzag Bladderwort; Illinois Endangered)
The Sundews (Drosera spp.)
Drosera rotundifolia (Round-leaved Sundew). Photo by Peter M. Dzuik.
The genus Drosera is characterized by sticky, gland-tipped hairs along the leaves of the plant that move in response to stimuli. When an insect lands on the leaf of the plant, the hairs slowly wrap around it, trapping the insect in place. From there, sessile glands secrete enzymes that digest the plant's prey. The nutrients that species in the Drosera genus receive through their prey allows them to survive in poor-nutrient soils.
The two species in the Drosera genus native to Illinois, Drosera intermedia (Narrow-leaved Sundew) and Drosera rotundifolia (Round-leaved Sundew), are listed as state threatened and state endangered respectively.
Pitcher Plants (Sarracenia spp.)
Sarracenia purpurea (Northern Pitcher Plant). Photo by Carol Freeman.
Unlike many other carnivorous plants, species in the genus Sarracenia capture their prey without the use of moving parts, opting instead to lure them into their 'pitchers,' highly modified, tubular shaped leaves that grow in rosettes at the base of the plant. Sarracenia purpurea, or Northern Pitcher Plant, is a state endangered species in Illinois, and is the only species in the Sarracenia genus that occurs in the state (Illinois Wildflowers).
Here's more on Sarracenia purpurea from Cael Dant, a master's student in the Fant Lab at the Chicago Botanic Garden studying the interactions of Sarracenia purpurea with other organisms and its surroundings:
The "pitchers" of Sarracenia purpurea. Photo by Cael Dant.
"I have loved carnivorous plants since I started growing them in high school, but for a long time I assumed I would never encounter them in the wild without getting on an international flight. Like many others, I held the preconceived notion that carnivorous plants were an “exotic” group to be found only in tropical rainforests far from where I grew up in Indiana. Imagine my surprise when I learned that many pitcher plant, sundew, and bladderwort species grew practically in my backyard! My thesis research at Northwestern and the Chicago Botanic Garden focuses on one of these plants, Sarracenia purpurea, and its ecological interactions with microbes and invertebrates in the Great Lakes region.
Sarracenia purpurea has wide, uncovered pitcher-shaped leaves that collect rainwater as opposed to producing digestive fluid like some other species do. Like other pitcher plants, it feeds on invertebrates that become trapped in its pitchers and drown. However, not everything that enters this plant dies—after initially sterile pitchers open and fill with rain, they are colonized by a rich community of bacteria that feed on trapped insects, as well as rotifers, protozoa, and midge and mosquito larvae that consume the bacteria, resulting in a diverse micro-ecosystem. In the plant’s northern range, the pitcher fluid even freezes over the winter, allowing highly specialized insect larvae to diapause before thawing and pupating in the spring.
The impact of prey capture on carnivorous plant physiology is well-studied, but the obvious interaction between these plants and their prey tends to overshadow their equally fascinating relationships with organisms like microbes. When I was planning my thesis project, I found a surprising lack of research on the impact of microbe and prey diversity on the plants’ ability to absorb nutrients and photosynthesize. I am working on an experiment to address this gap by taking physiological measurements from plants inoculated with different microbial communities and fed with different types of prey, which I hope will lead to a better understanding of this plant’s extensive interactions with other organisms in its unique and vulnerable habitat."
Botanical illustration of Sarracenia purpurea by Cael Dant.
Whether through bladders, sticky-traps, or pitfalls, the rare carnivorous plants of Illinois not only delight, but provide for their ecosystems. This Halloween season, we encourage you to keep an eye out for these charismatic carnivores and remember, some of the strangest and most fascinating plants on the planet may be growing in your own backyard!
Poster with botanical illustrations of some of the main carnivorous plants of North America. Created by Cael Dant.
References
Grothjan, J. & Young, E. 2022. Bacterial Recruitment to Carnivorous Pitcher Plant Communities: Identifying Sources Influencing Plant Microbiome Composition and Function. Frontiers in Microbiology 13. 10.3389/fmicb.2022.791079
Illinois Endangered Species Protection Board. 2020. "Checklist of
Endangered and Threatened Animals and Plants of Illinois". Illinois Endangered
Species Protection Board, Springfield, Illinois. 10 pp. Published online at
https://www2.illinois.gov/dnr/....
Illinois Wildflowers. Northern Pitcher Plant. Retrieved October 7, 2025, from https://www.illinoiswildflower...
Jennings, D. & Rohr, J. 2011. A review of the conservation threats to carnivorous plants. Biological Conservation 144, no. 5 (2011): 1356-1363. https://doi.org/10.1016/j.bioc....
Lotzof, K. "Carnivorous plants: the meat-eaters of the plant world." Natural History Museum. Retrieved October 7, 2025, from https://www.nhm.ac.uk/discover...
Melchior P., Reiss E., Payne Z., Vuong N., Hovorka K., Lindsay HL., Diaz GR., Gaire T., Noyes N. 2024. Analysis of the northern pitcher plant (Sarracenia purpurea L.) phytotelm bacteriome throughout a temperate region growing season. PLoS One 19, no. 7. doi:10.1371/journal.pone.0306602.
Petruzzello, M. "Bladderwort". Britannica. Retrieved October 7, 2025, from https://www.britannica.com/plant/bladderwort
Schaefer, J. 2021. "From Poetry to Pulp Fiction: Carnivorous Plants in Popular Culture". Biodiversity Heritage Library. https://blog.biodiversitylibra...
T. Lawrence Mellichamp. "Drosera". Flora of North America. Retrieved October 7, 2025, from https://floranorthamerica.org/...
U.S. Forest Service. Purple Pitcherplant, Saddle Flower (Sarracenia purpurea L.). Retrieved October 7, 2025, from https://www.fs.usda.gov/wildfl...
Written by Madeleine Bagnall, Plants of Concern Program Assistant.