Scientists have characterised the movement of the Venus flytrap's aquatic cousin in detail for the first time.
The carnivorous Aldrovanda vesiculosa, also known as the waterwheel plant, snaps its "trap" shut ten times faster than the flytrap.
As it is quite rare in the wild, the plant's mechanism has not previously been studied in great detail.
It is thought that the waterwheel and the flytrap may share a common ancestor.
However there is no fossil evidence for what this ancestor might have looked like.
"This is one of the main questions in the carnivorous plant community," says Dr Simon Poppinga, an author on the study.
"Snap traps evolved only once in plants. There are two different mechanisms. Which one was first?"
The study ... found that the waterwheel doesn't use quite the same method as the flytrap.
Editor's note: Read the full study (behind paywall)
Read full, original post: Waterwheel: Ten times faster than a Venus flytrap