Alnus glutinosa (L.) Gaertn.
  • Fruct. Sem. Pl.
  • Black alder, European alder

Cite taxon page as 'WFO (2020): Alnus glutinosa (L.) Gaertn. Published on the Internet; Accessed on: 26 Oct 2020'

General Information

Trees , to 20 m; trunks often several, crowns narrow. Bark dark brown, smooth, becoming darker and breaking into shallow fissures in age; lenticels pale, horizontal. Winter buds stipitate, ellipsoid to obovoid, 6--10 mm, apex obtuse; stalks 2--5 mm; scales 2--3, outer 2 equal, valvate, usually heavily resin-coated. Leaf blade obovate to nearly orbiculate, 3--9 × 3--8 cm, leathery, base obtuse to broadly cuneate, margins flat, coarsely and often irregularly doubly serrate to nearly dentate, major teeth acute to obtuse or rounded, apex often retuse or obcordate, or occasionally rounded; surfaces abaxially glabrous to sparsely pubescent, often more heavily on veins, both surfaces heavily resin-coated. Inflorescences formed season before flowering and exposed during winter; staminate catkins in 1 or more clusters of 2--5, 4--13 cm; pistillate catkins in 1 or more clusters of 2--5. Flowering before new growth in spring. Infructescences ovoid to nearly globose, 1.2--2.5 × 1--1.5 cm; peduncles 1--10(--20) mm. Samaras obovate, wings reduced to narrow, thickened ridges. 2 n = 28.

  • Provided by: [C].Flora of North America @
    • Source: [
    • 1
    • ]. 

    "Tree, with young parts very glutinous; lvs broadly oval to obovate or subrotund, broadly rounded above or retuse, broadly cuneate to rounded at base, finely serrate, with 5–8 principal veins on a side; fruiting catkins very glutinous, evidently pedunculate in axillary infls, 1.5–2.5 cm, 10–13 mm thick; frs elliptic or suborbicular, 2.5–3.5 mm, narrowly bordered; 2n=28. Native of Eurasia and n. Afr., planted especially along roadsides and occasionally escaped in our range. (A. alnus; A. vulgaris)"

  • Provided by: [D].New York Botanical Garden
    • Source: [
    • 2
    • ]. 


    Tree, 20-30 m high; young growth glutinous; monoecious. Leaves petiolate; blade elliptic to broadly ovate, 60-120 mm long, apex truncate, base cuneate, margins shallowly toothed, sticky when young, later glossy green; petiole up to 50 mm long. Flowers: male catkins 50-100 mm long, pendulous, reddish; female catkins 200 mm long, dark brown to black; Nov.-May. Fruit cone-like with 5-lobed scales, persistent; nutlets winged.

  • Provided by: [B].e-Flora of South Africa
    • Source: [
    • 4
    • ]. 


    Dry Grassland.

  • Provided by: [B].e-Flora of South Africa
    • Source: [
    • 4
    • ]. 


    Native to Europe.

  • Provided by: [B].e-Flora of South Africa
    • Source: [
    • 4
    • ]. 


    Other Local Names

    Black alder, European alder


     Information From

    World Flora Online Data. 2017.
    • A CC0 1.0 Universal (CC0 1.0).
    e-Flora of South Africa
    e-Flora of South Africa. v1.21. 2018. South African National Biodiversity Institute.
    • B All Rights Reserved
    Flora of North America @
    'Flora of North America @ eFloras (2008). Published on the Internet [accessed August 2016]' Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
    • C Flora of North America Association
    New York Botanical Garden
    Descriptions of plants should be attributed to the full citation for each individual article, chapter or book that is the source for each record, which should include the authors of original publication.
    • D Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
    World Flora Online consortium
    World Flora Online Data. 2018.
    • E CC0 1.0 Universal (CC0 1.0).
    International Union for Conservation of Nature v.3
    IUCN 2019. The IUCN Red List of Threatened Species. Version 2019-1.
    • F See IUCN Terms and conditions of use
    Global Tree Search
    BGCI. 2018. GlobalTreeSearch online database. Botanic Gardens Conservation International. Richmond, U.K. Available at Accessed on 30/11/2018.
    • G Botanic Gardens Conservation International
    International Union for Conservation of Nature
    IUCN 2016. IUCN Red List of Threatened Species. Version 2016-2
    • H All Rights Reserved