Alnus incana (L.) Moench
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Tall colonial shrub or small tree; winter buds evidently stalked, with 2–3 equal scales; lvs oval, elliptic, or ovate, broadest near or below the middle, obtuse to short- acuminate, sharply and irregularly double-serrate or almost lobulate, broadly obtuse to rounded at base, with mostly 8–14 principal veins on a side, soon becoming pale and glaucous beneath, ± pubescent, especially on the veins, not glutinous; staminate catkins mature before the lvs begin to open; anthers virtually sessile; fruiting catkins mostly sessile or only short-pedunculate, crowded in small, naked infls, 1–1.5(2) cm, seldom much over 1 cm thick; frs 2–3.5 mm, narrowly coriaceous-winged or merely thin-margined; 2n=28. Wet soil; circumboreal, s. to Md., W.Va., Ill., and the w. cordillera. E. Amer. pls, as here described, are var. americana Regel (A. rugosa; A. incana ssp. rugosa)