Touch Receptor of Venus Flytrap, Dionaea muscipula

Numerous small structures (stellate trichomnes) protrude from the surface of marginal hairs, outer leaf surface, and stem of Dionaea muscipula Ellis. None are present inside the trap. Mechanical stimulation causes small action potentials and eventual closure of the trap, independently of the sensitive trigger hairs. Subthreshold stimulation of these structures appears to sensitize the trigger hairs and facilitate closure of the trap. This suiggests that these structures act as touch sensors or receptors.