It is well known from experiments that bacterial species Bacillus subtilis exhibit various colony patterns. These are essentially classified into five types in the morphological diagram, depending on the substrate softness and nutrient concentration. (A) diffusion-limited aggregation-like; (B)...

As a hydrodynamic analog of the dendritic crystal growth we have performed viscous fingering experiments under the influence of linear anisotropy through a single straight groove. One finger always tends to grow faster on the groove, accompanied by side branches. It was found that (1) the...

Colonies of bacterial species called Bacillus subtilis have been found to grow two-dimensionally and self-similarly on agar plates through diffusion-limited processes in a nutrient concentration field. We obtained a fractal dimension of the colony patterns of D=1.73±0.02, very close to that of...