One of Darwins many interests was carnivorous plants and in his writings on the subject he proposed that the waterwheel plant Aldrovanda vesiculosa:
Aldrovanda vesiculosa project (pics.) was the closes relative of the venus flytrap. Now genetic studies have revealed that the waterwheel is the closest living relative of the flytrap.
"Evolutionary studies have shown that carnivory arose independently within several lineages of flowering plants. However, it has been unclear whether snap-traps evolved twice or only once, because the aquatic waterwheel plant (Aldrovanda vesiculosa) has been poorly studied. Using DNA sequences from four genes, Cameron et al. show that Aldrovanda is sister to Venus’ flytrap (Dionaea muscipula), and that this pair is sister to the sundews (Drosera). These results indicate that snap-traps are derived from adhesive flypaper-traps and share a common ancestry, despite the fact that this fast action mechanism is used by both a terrestrial and an aquatic species."
Kenneth M. Cameron, Kenneth J. Wurdack, and Richard W. Jobson. Molecular evidence for the common origin of snap-traps among carnivorous plants. American Journal of Botany (in press)
There is a press release on the research here:
Page not found » New York Botanical Garden
This shows yet again what a great scientist Charles Darwin was.