Bogs and Acidic Peatlands of Southern New England by Marsha C. Salett
Alnus incana (L.) Moench
BETULACEAE (Birch Family)
EtymologyAlnus is the classical Latin name for alder; incana is Latin for hoary or gray.
DescriptionA deciduous, broad-leaved shrub or small tree that reaches 15' tall, speckled alder is named for the long, whitish lenticels that mark its dark brown or blackish-gray bark. Both speckled alder and smooth alder (A. serrulata) have multiple trunks and form dense thickets; speckled alder is more common in New England. Alders have shallow, matted root systems that help prevent erosion and enrich soil in association with nitrogen-fixing bacteria that are harbored in the root nodules.
Wetland indicator statusFACW+
Plant Heightto 15 feet
LeavesDeciduous, alternate, simple, with coarsely double-toothed (coarse and fine teeth) margins that are often wavy, 2-3" long; oval, elliptical, or ovate, broadest at or below the middle, with rounded base; pale or whitened undersides.
Flower/InflorescenceMale and female flowers different; clustered in catkins at tips of separate branches. Male catkins: purplish, elongate (1-3"), drooping. Female catkins are oval, somewhat drooping (1/4-1/2"), and turn woody when mature; they look like miniature pinecones.
Flowering PeriodMarch-May, before leaves appear Male and female catkin buds develop in autumn and persist over the winter; buds are covered with 2-3 equal scales
FruitTiny achene (nutlet) in axils of cone-like female catkin.
Fruiting PeriodAugust-October; mature cones persist throughout winter.
HabitatWooded and shrub swamps, stream banks, margins of ponds and lakes.
RangeNewfoundland to British Columbia, south to Maryland and Illinois.
(c) 1998-2006 Marsha C. Salett