Flora of North America species comparison

dark gray, smooth, becoming blackish and breaking into shallow vertical plates in age;

lenticels inconspicuous.

blade narrowly ovate or lanceolate to narrowly elliptic, 5–9 × 3–6 cm, leathery, base narrowly to broadly cuneate or narrowly rounded, margins flat, sharply and coarsely doubly serrate, rarely evenly and densely short-serrate, major teeth sharp, acuminate, secondary teeth distinctly larger, apex long to short-acuminate, rarely acute;

surfaces abaxially glabrous to sparsely pubescent or infrequently villous, moderately resin-coated.

blade broadly to narrowly ovate or elliptic, 3–11 × 3–8 cm, base rounded, obtuse, or cuneate, sometimes nearly cordate, margins serrulate to coarsely doubly serrate, apex acute to rounded;

surfaces abaxially glabrous to tomentose, lightly to heavily resin-coated.

formed season before flowering and exposed during winter; staminate catkins in 1 or more clusters of 3–6, 3.5–10 cm; pistillate catkins in 1 or more clusters of 2–7.

staminate catkins in 1 cluster of 2–4, formed late in growing season before flowering and exposed during winter; pistillate catkins in 1 or more clusters of 2–10, formed season before blooming, enclosed in buds during winter, exposed with new growth in spring.

ovoid, ellipsoid, or nearly cylindric, 1–2.5 × 0.8–1.5 cm;

peduncles 5–10 mm.

ovoid to ellipsoid or nearly cylindric;

peduncles relatively long, thin.

buds stipitate, ovoid, 4–8 mm, apex rounded;

stalks 1.5–4 mm;

scales 2, equal, valvate, sometimes incompletely covering underlying leaves, moderately resin-coated.

buds nearly sessile, ovoid, apex acuminate;

stalks usually not over 1 mm;

scales 4–6, unequal, imbricate.

before new growth in spring.

with new growth in spring.

elliptic to obovate, wings narrower than body, irregular in shape, leathery.

elliptic to obovate, wings wider than body, membranaceous.