Alnus incana subsp. rugosa (Du Roi) R.T.Clausen

Shrubs , open, spreading, to 9 m. Bark dark grayish to reddish brown, smooth; lenticels whitish, prominent, horizontal. Winter buds parallel to twig, ellipsoid, 3--7 mm, apex acute or obtuse; stalks 2--4 mm. Leaf blade ovate to elliptic, 4--11 × 3--8 cm, firm, base cuneate to narrowly rounded, margins usually coarsely doubly serrate, toothed to base, apex acute or short-acuminate to slightly obtuse; surfaces abaxially often glaucous, glabrous to sparsely pubescent, often more densely so on veins, slightly to not noticeably resin-coated. Inflorescences: staminate catkins in 1 or more clusters of 2--4, 2--7 cm; pistillate catkins in 1 or more clusters of 2--6. Infructescences ovoid, 1--1.7 × 0.8--1.2 cm; peduncles 1--5 mm. 2 n = 28.

It grows along streams and lake shores. It suits hardiness zones 2-6.

The buds and young catkins are edible but not very tasty. The inner bark can be eaten raw, cooked or dried and ground into flour. It should be aged for a few days before eating.

Can be grown by seedlings.