A tree with smooth bronze bark. Leaves: broadly ovate, acute, sharply serrate except at the rounded subcordate and often unequal base. Flowers: staminate aments clustered with light brown scales, pistillate aments short-stalked, with ovate acute green scales. Fruit: strobiles cylindrical, puberulous, erect or pendulous on slender stalks.
The Black Birch is a small tree with slender spreading pendulous branches and lustrous copper or bronze bark. The leaves are broad, and pointed at the apex, pale green above, and yellowish with minute glandular dots below, their short stems often slightly reddened, and they turn completely yellow in the autumn before falling.
Betula alba var. papyrifera, or Paper Birch, is a large forest tree, with outer lustrous white bark peeling off in thin layers, and disclosing the inner orange surface. The leaves are ovate, very pointed, also coarsely double-toothed all round, and rounded at the base.
Betula glandulosa, or Dwarf Birch, is a small shrub growing from one to five feet high, or procumbent at high altitudes, with glandular, warty twigs, and rounded leaves, bluntly toothed.