Shrubs , open to rather densely ascending, to 10 m. Bark light gray, smooth; lenticels small, inconspicuous. Winter buds stipitate, ellipsoid to obovoid, 3--6 mm, apex mostly rounded; stalks 2--4 mm; scales 2, equal, valvate, moderately to heavily resin-coated. Leaf blade broadly elliptic to obovate, 5--14 × 3.5--8 cm, leathery, base broadly to narrowly cuneate, margins flat, serrulate, without noticeably larger secondary teeth, apex obtuse to rounded; surfaces abaxially glabrous to moderately villous, slightly to moderately resin-coated. Inflorescences formed season before flowering and exposed during winter; staminate catkins in 1 or more clusters of 2--5, 3--8.5 cm, stamens 4; pistillate catkins in 1 or more clusters of 3--5. Flowering before new growth in spring. Infructescences ovoid-ellipsoid, 1--2.2 × 0.6--1.2 cm; peduncles 1--3(--5) mm. Samaras obovate, wings narrower than body, irregularly elliptic or obovate, leathery. 2 n = 28.
"Much like no. 2 [Alnus incana (L.) Moench]; lvs elliptic to obovate, tending to be broadest above the middle, obtuse to rounded, serrate with very fine, sharp, nearly regular teeth, obtuse to cuneate at base, beneath green and glabrous, or thinly pubescent on the veins; 2n=28. Wet soil; N.S. and s. Que. to n. Fla., w. to n. Ind., s. Ill., Mo., Okla., and w. Tex."
|Smooth alder, hazel alder|