Polarity in mechanoreceptor cells of trigger hairs of Dionaea muscipula Ellis.

Both the apical and the basal cell poles of the sensory cells in trigger hairs of Dionaea muscipula are structured identically. A complex of concentrically arranged endoplasmic reticulum cisternae occupies each of the poles. One to four vacuoles are enclosed within the central cisterna and contain polyphenols (deposits of "tannin"). Structural polarity, whether symmetric or asymmetric, as well as the occurrence of abundant endoplasmic reticulum and numerous mitochondria are characteristics of the perception cells of most animals and plants.