Waterwheel Plant
Quick Facts & Botanical Stats
Species Overview
What is the Waterwheel Plant? The waterwheel plant (Aldrovanda vesiculosa) is a rootless, free-floating aquatic carnivorous plant in the Droseraceae family. Is it related to the Venus flytrap? Yes, it is the closest living relative of the Venus flytrap, using active underwater snap traps to catch aquatic invertebrates. The traps are arranged in wheel-like whorls around a central floating stem, giving the plant its common name.
Physical Appearance & Anatomy
What does a waterwheel plant look like? The plant grows as a submerged, rootless stem. How are the traps arranged? The stem produces whorls of 8 leaves arranged like spokes on a waterwheel. Each leaf ends in a small, active snap trap (2 to 3 mm) lined with trigger hairs and sharp, interlocking teeth along the margins. The leaves contain air bubbles in the petioles to keep the plant floating.
Habitat & Growth Behavior
Where does the waterwheel plant grow? It grows in clean, shallow, warm, acidic, nutrient-poor freshwaters, such as lake margins and bog ponds. How fast is the underwater trap? When an aquatic insect touches the trigger hairs, the trap snaps shut in less than 20 milliseconds, making it one of the fastest movements in the plant kingdom, especially under water.
Ecological Role & Symbioses
What does the waterwheel plant eat? It feeds on small aquatic invertebrates, including water fleas (Daphnia), mosquito larvae, copepods, and protozoa. How does it help the water ecosystem? It acts as a natural biological filter and mosquito predator in shallow waters, recycling nutrients in low-nitrogen wetlands.
Reproduction, Lifecycle & Propagation
The waterwheel plant reproduces sexually and asexually. In summer, it occasionally produces single, small white flowers that float on the water surface and are insect-pollinated. In cold climates, it survives winter by forming dense, dormant winter buds (turions) that sink to the bottom of the pond. In spring, the turions rise and sprout. It propagates mostly by stem division.
Conservation Status & Environmental Threats
Aldrovanda vesiculosa is listed as Endangered on the IUCN Red List. It has vanished from over 90% of its historic wild locations globally. Threats include water pollution (eutrophication), wetland drainage, and invasive species. It requires pristine, low-nutrient water conditions and is protected in nature reserves in Europe and Japan.
Interesting Fun Facts
- The waterwheel plant is the closest living relative of the Venus flytrap, using active snap traps to catch prey under water.
- The underwater traps snap shut in less than 20 milliseconds, faster than the blink of an eye.
- The plant is rootless and floats freely, absorbing all nutrients from the tiny water insects it traps and digests.
- To survive freezing winter temperatures in Europe, the plant forms tight, sinking winter buds called turions.
Related Plants
Common Bladderwort
Least ConcernWhat is a bladderwort? The common bladderwort (Utricularia vulgaris) is an aquatic carnivorous plant in the Lentibulariaceae family. Floating freely in ponds, it lacks roots and leaves. How does it catch prey? It is famous for its suction traps, which are small, air-filled bladders. When an aquatic insect touches the trigger hairs, the bladder door opens, sucking in the prey in milliseconds, making it one of the fastest movements in nature.
Venus Flytrap
EndangeredWhat is a Venus flytrap? The Venus flytrap (Dionaea muscipula) is a small carnivorous plant belonging to the Droseraceae family. Native exclusively to the nitrogen-poor coastal bogs of North and South Carolina, it is globally famous for its rapid, active leaf traps. Why is the Venus flytrap carnivorous? Because it grows in nutrient-starved, acidic soil, it has evolved traps to catch insects, digesting them to absorb essential nitrogen and phosphorus. Charles Darwin famously described the Venus flytrap as 'one of the most wonderful plants in the world'.