Growth of DX on agar as seen at the light microscope. The filament starting from 3 cells in (1) grows at the periphery (2, 3) and in (4) the specific curvature appears at both ends when the filament is still unique. In (5) the first ramification occurs, enlarged in insets that show duplication and rupture of the filament. In (6) the circle is closed and insets show the rapid cell progression at the closure point. In (7) many lateral ramifications emerge. In (8) these ramifications converge in a few big trunks displaying the specific curvature. In (9) the final shape of the colony is shown. Scale bar: 1–4 = 100 μm; 5–8 = 500 μm; 9 = 1 cm.