Changes in normalized cell length (NCL) and tissue volume densities (V-v) of five trap tissues were studied during reopening of fully closed traps of Venus's flytrap (Dionaea muscipula Ellis). Four trap-reopening stages were identified based on morphological changes observed in time-lapse video: (1) Sealed-the last stage of trap closure before the trap began to reopen; (2) Deappressed-characterized by a convex bulge in the upper region of the trap; (3) Release-in which the bulge region moved closer to the trap margins initiating lobe separation while the marginal tynes remained interdigitated; (4) Fully opened-the trap lobes assumed a morphology similar to that of a nonstimulated trap. Morphological changes associated with trap reopening occurred as a series of relatively fast (1-5 h) and slow (10-15 h) movements and appeared to be a reversal of the morphologies observed during trap closure. However, comparison of changes in NCL of trap tissues during closure and reopening showed very little statistical correlation indicating that the tissue dynamics associated with trap closure were not simply reversed during reopening. Although the precise cell movements that provided driving force for trap morphological change were not delineated in this study, comparison of NCL data suggested that tissues in the trap lobe were alternately ''active'' and ''quiescent'' in temporally and regionally complex patterns. Changes in the NCL of analogous tissues on opposite sides of the mid-trap tissues within a trap region showed high positive correlation values, which indicated the possibility of coordinated activity in opposing tissues.