Scanning electron micrograph (SEM) of a number of a large grouping of Gram-negative Legionella pneumophila bacteria. Note the presence of polar flagella, and pili, or long streamers. a number of these bacteria seem to display an elongated-rod morphology. L. pneumophila are known to most frequently exhibit this configuration when grown in broth, however, they can also elongate when plate-grown cells age, as it was in this case, especially when they've been refrigerated. The usual L. pneumophila morphology consists of stout, "fat" bacilli, which is the case for the vast majority of the organisms depicted here. Mag., x6500