Induction of growth of F colonies on minimal medium (MMA) by maculae: a R macula; b M macula; c E. coli macula. (Day 7) Middle row: macroscopic appearance, top and bottom row – magnified details (see inserts the macroscopic structure). Note the smooth, non-interactive edges without scouts. d Helper colony of E. coli (arrow) in center of dense sowing of F. (Day 7). Bars: 1 cm in all macro-, 100 μm in all micro-photographs.