This volume of the series The Plant Viruses is devoted to viruses with rod-shaped particles belonging to the following four groups: the toba- moviruses (named after tobacco mosaic virus), the tobraviruses (after to- bacco rattle), the hordeiviruses (after the latin hordeum in honor of the type member barley stripe mosaic virus), and the not yet officially rec- ognized furoviruses (fungus-transmitted rod-shaped viruses, Shirako and Brakke, 1984). At present these clusters of plant viruses are called groups instead of genera or families as is customary in other areas of virology. This pe-...