Betula nigra L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Tree to 30 m, the brown bark exfoliating in thin layers, scaly- roughened on larger trunks; lvs ovate-oblong or deltoid-ovate, 4–8 cm, acute, sharply double-serrate above, entire toward the cuneate base, tomentose beneath when young, soon glabrescent on the surface but remaining softly villous on the veins beneath and tomentose on the petiole; lateral veins 6–10 pairs; fruiting catkins on peduncles 5–8 mm, cylindric, 1.5–3 cm; scales pubescent, 6–8 mm, parted above the middle into 3 oblong lobes; frs pubescent, depressed-ovate, 3–4 × 4–7 mm, the body 2.5–4 mm wide. Swamps and flood-plain forests; N.H. to Fla., w. to s. O., se. Minn., e. Kans. and Tex.
river birch, red birch