Cellular pattern formation in the system succinonitrile-0.075 wt% acetone in a supercritical regime is analyzed on the basis of a set of purely diffusive space experiments in bulk samples. Order-disorder investigations using the minimal-spanning-tree approach yield steady-state patterns for the microgravity experiments of an order which suggests a honeycomb structure disturbed by Gaussian noise. The most important morphology parameter, primary spacing of the cellular array, is critically discussed in comparison to the established theoretical models. It is found that analytical models fail to describe cell sizes in supercritical cellular growth. In contrast, excellent agreement is demonstrated using the numerical model of Hunt. This implies that modelling supercritical cellular growth requires consideration of interacting solute diffusion fields ahead of the cells and free development of cell shapes,