False-colour scanning electron micrograph (SEM) of a nitrogen-fixing bacterium, Rhizobium legumino- sarum, on the root hair of a pea plant, Pisum sativum. Rhizobium is a free-living soil bacterium for most of its life, but at times forms a symbiotic association with the roots of leguminous plants. In return for breaking down atmospheric nitrogen & converting it into a form the plant can use, the bacterium gains access to the plant's carbohydrate food stores & is kept safe in the plant's tissue. Magnification: x9285 at 35mm size, x14,900 at 6x6cm size. (More detailed information available on request). Full colour version: green on yellow. BW original is B238/23M. Reference: MICROCOSMOS, figure 5.18, page 98. See