Flora of North America species comparison

dark brown, smooth, becoming darker and breaking into shallow fissures in age;

lenticels pale, horizontal.

thin, close or exfoliating in thin sheets, becoming thicker and frequently furrowed or broken in age;

lenticels often present, prominent, sometimes becoming greatly expanded horizontally.;

bark and wood strongly tanniferous.

blade obovate to nearly orbiculate, 3–9 × 3–8 cm, leathery, base obtuse to broadly cuneate, margins flat, coarsely and often irregularly doubly serrate to nearly dentate, major teeth acute to obtuse or rounded, apex often retuse or obcordate, or occasionally rounded;

surfaces abaxially glabrous to sparsely pubescent, often more heavily on veins, both surfaces heavily resin-coated.

3-ranked, occasionally nearly 2-ranked.

formed season before flowering and exposed during winter; staminate catkins in 1 or more clusters of 2–5, 4–13 cm; pistillate catkins in 1 or more clusters of 2–5.

perianth of 4(–6) sepals, well defined, minute, membranaceous.

2–3 per scale, scales arranged in conelike catkins;

perianth not obvious;

ovules with 1 integument.

ovoid to nearly globose, 1.2–2.5 × 1–1.5 cm;

peduncles 1–10(–20) mm.

1–4 cm, conelike, composed of many scales;

scales either persistent or deciduous with fruits, crowded, small, woody or leathery.

tiny samaras, lateral wings 2, membranous, sometimes reduced to ridges;

pericarp thin, leathery.

buds stipitate, ellipsoid to obovoid, 6–10 mm, apex obtuse;

stalks 2–5 mm;

scales 2–3, outer 2 equal, valvate, usually heavily resin-coated.

before new growth in spring.

obovate, wings reduced to narrow, thickened ridges.

and branches terete.

twigs and buds often covered with small to large, resinous glands;

pith triangular in cross section.

= 28.