A genus of mycelium-forming bacteria. They are found in soil and in root nodules in a variety of non-leguminous, dicotyledonous (Dicotolydoneae) plants. The root nodules can bring about the fixation of atmospheric nitrogen. F. alni occurs in coralloid nodules on the roots of alder (Alnus). Nodules are generally present only near the soil surface.
Subjects: Plant Sciences and Forestry.