Family: Betulaceae
black alder, European alder
[Alnus alnus (L.) Britton, more...]
Robert R. Kowal
Paul Drobot
University of Wisconsin-Stevens Point, Robert W. Freckmann Herbarium (UWSP)
Etymology: Alnus: ancient Latin name derived from the Celtic, "growth along streams"
Plants: perennial tree to 40'-60' tall, often with several trunks and a narrow crown; dark brown, smooth bark becoming darker and breaking into fissures with time; pale, horizontal lenticels
Leaves: leaf obovate to nearly oval, leathery, edges coarsely and often irregularly doubly toothed; heavily coated with resin on top and bottom
Flowers: winter buds stalked; male catkins in 1 or more clusters 1 1/2"-5" long; blooms in early spring
Fruits: oval to nearly round, stalked fruit clusters; samaras obovate, wings only narrow, thickened ridges
Habitat: moist to wet; streambanks, floodplains, wetland edges
Conservation Status: Introduced - locally established; potentially invasive
Plants: perennial tree to 40'-60' tall, often with several trunks and a narrow crown; dark brown, smooth bark becoming darker and breaking into fissures with time; pale, horizontal lenticels
Leaves: leaf obovate to nearly oval, leathery, edges coarsely and often irregularly doubly toothed; heavily coated with resin on top and bottom
Flowers: winter buds stalked; male catkins in 1 or more clusters 1 1/2"-5" long; blooms in early spring
Fruits: oval to nearly round, stalked fruit clusters; samaras obovate, wings only narrow, thickened ridges
Habitat: moist to wet; streambanks, floodplains, wetland edges
Conservation Status: Introduced - locally established; potentially invasive
Flora of North America: Flora of North America Floristic Rating: Wetland Indicator = FACW- WIS DNR-Bureau of Endangered Resources: Detailed information on Wisconsin invasive species including decription, habitats, control methods Invasive And Exotic Species of North America: Descriptions, management issues, warnings, photos, etc. USDA Plants Database: Federal Distribution and detailed information including photos University of Wisconsin - Green Bay: Trees: Photos, descriptions, information USDA Agricultural Research Service (ARS): Images of seeds, fruits, embryos, etc. Virginia Tech Dept. of Forestry, College of Natural Resources: detailed description and photographs Landscape Plants of the Upper Midwest; UW-Extension: Interactive guide providing information on cultivation including: soil, zone, growth rate, landscape uses, pruning, light requirements; with photos and Latin name pronounciation
Paul Drobot
Paul Drobot
Paul Drobot
Paul Drobot
Paul Drobot
Paul Drobot
Kurt Stüber
Botanical Illustration
Botanical Illustration
Robert W. Freckmann
Michael Clayton
