What prey do underground leaves of Philcoxia trap and digest?

Underground leaves of Philcoxia trap and digest nematodes.

Philcoxia is a small genus of Brazilian plants with leaves that grow beneath or close to the sandy soil surface. Those leaves bear sticky, stalked glands that can capture microscopic roundworms, or nematodes, passing across them. This hidden trapping strategy is one of the genus’s most unusual adaptations.

Researchers first became interested after observing nematodes on the leaves of Philcoxia minensis. Experiments later used nitrogen marked in nematode tissue to show that the plant digests the prey and absorbs nutrients from it. The leaves also produce phosphatases, enzymes commonly associated with carnivory.

The discovery helped distinguish Philcoxia from plants that merely have unusual underground leaves. Early testing did not detect one expected digestive enzyme, but that result did not rule out carnivory. A common mistake is to choose insects such as midges or mosquitoes; Philcoxia’s documented prey are nematodes, not flying insects.