Wood anatomy of <em>Betula uber</em> (Ashe) Fernald is described and compared with woods of other birches belonging to series <em>Humiles</em> and series <em>Costatae</em>. Anatomically, wood of <em>B. uber</em> is typical of birches in general. On the basis of pore size and frequency, fiber characteristics, axial xylem parenchyma distribution, and absence of aggregate rays, it is argued that <em>B. uber</em> is properly classified in series <em>Costatae</em>. Resolution of its relationships within series <em>Costatae</em> is not apparent from wood data.