The stems contained a central cavity which expanded upwards and also increased in diameter. Both processes might decrease the mechanical strength of the stem. Nonetheless, no difference was found in the development of the cavities in stems that had bent by day 7 of vase life and stems that had not yet bent. This suggested that the central cavity is not important in determining stem bending. A similar conclusion can be reached from a comparison with other cultivars. Stems of cv. Cora, which also showed early bending (van Doorn et al., 1994; present preliminary experiments) had a cavity just as in cv. Tamara. However, cv. Mickey, which did not show stem bending in most vase life experiments (van Doorn et al.,1994; present preliminary experiments) also had a cavity similar to cv. Tamara. Finally, cv. Nikita did not bend (van Doorn et al. 1994) and had no cavity in the stems. These data indicate absence of a relationship between the presence of a stem cavity and stem bending.