Streptomyces bacteria. Coloured scanning electron micrograph (SEM) of chains of spores of the soil bacteria Streptomyces sp. Streptomyces species are natural producers of various antibiotics, including streptomycin. Streptomyces bacteria share many characteristics with fungi. The bacteria commonly grow in the soil as branching networks of filaments and chains of spores (as seen here). These spore chains, produced at the tips of aerial mycelia, may be straight or coiled and they produce a dark pigment in the bacteria when it is seen in culture. Magnification: x3,400 at 5x7cm size. x12,000 at 10x7 inch size.