The bacterial and fungal flora of the bark, wood, and pith of alder, black cottonwood, maple, and willow

The occurrence and distribution of symbiotic cauloplane organisms on dormant cuttings of 1- to 2-year-old stems of alder, black cottonwood, maple, and willow were determined from tissue samples removed to 2% malt extract and nutrient broth agars, and from scanning electron micrographs of the bark surfaces. Fungal and bacterial symbionts were found to be confined to the bark surfaces, where their occurrence was related to the surface topography. Inner bark, wood, and pith were virtually aseptic.