Alnus Mill. (Betulaceae)

A genus of about twenty-five to thirty-five species of shrubs and trees; of subarctic to warm temperate regions of the Northern Hemisphere, and in montane situations south to n. South America.

Two species occur in North Carolina, both are considered native to the state.

1. Fruit narrowly winged; winter buds stalked, covered by 2-3 equal scales...A. serrulata (Tag alder)

Bark of Alnus serrulata (Photo: S.J. Baskauf, CC BY-NC-SA 3.0; Bioimages)

Twig of Alnus serrulata (Copyright W. Cook)

Leaf scar of Alnus serrulata (Photo: A. Krings, CC BY-NC-SA 3.0)

Leaf of Alnus serrulata (Photo: A. Krings, CC BY-NC-SA 3.0)

Leaves of Alnus serrulata (Copyright W. Cook)

Flowers of Alnus serrulata (Copyright W. Cook)

Inflorescences of Alnus serrulata (Copyright W. Cook)

Female flowers of Alnus serrulata (Copyright W. Cook)

Fruit of Alnus serrulata (Copyright W. Cook)

Detail of infructescence of Alnus serrulata (Copyright W. Cook)

N.C. distribution of Alnus serrulata

U.S. distribution of Alnus serrulata

Alnus serrulata (Tag alder)
(Common; streambanks, bogs, wet thickets; Mt, Pd, CP; Fl: Feb-Mar; Fr: Aug-Oct)

1. Fruit broadly winged; winter buds sessile, covered by multiple, imbricate, unequal scales...A. alnobetula subsp. crispa (Green alder)

Bark of Alnus viridis (Photo A. Krings, CC BY-NC-SA 3.0)

Twig of Alnus viridis (Photo A. Krings, CC BY-NC-SA 3.0)

Leaves of Alnus viridis (Photo A. Krings, CC BY-NC-SA 3.0)

Leaves of Alnus viridis (Copyright Smithsonian Institution)

Flowers of Alnus viridis (coming soon)

Fruit of Alnus viridis (Photo A. Krings, CC BY-NC-SA 3.0)

N.C. distribution of Alnus viridis

U.S. distribution of Alnus viridis

Alnus alnobetula subsp. crispa (Green alder)
(Rare [though locally common]; grassy balds, shrub balds, spruce-fir forests, and rock outcrops at high elevations [1600-1900m] in the Roan Mountain Massif, Mitchell and Avery counties, NC; Mt; Fl: May-Jun, Fr: Jul)