Plants of South Eastern New South Wales
Alnus glutinosa
Common name
Black Alder, Common Alder, European Alder
Family
Betulaceae
Where found
Wet forest, along streams, near lakes, and damp ground. Tolerant of water logged conditions. Canberra, Katoomba, and Kosciuszko National Park.
Notes
Introduced deciduous tree to 20 m high. Bark grey to dark brown, smooth in young trees, fissured, becoming deeply furrowed in older trees. Branchlets smooth, new buds sticky and with resinous warts. Leaves alternating up the stems, 3-14 cm long, 30–110 mm wide, upper surface glossy dark green, lower surface paler green with rusty-brown hairs in the angles of the veins, margins wavy and toothed. Separate male and female flowers on the same plant. Flowers in catkins, in clusters of 2-5. Male catkins 25-160 mm long, reddish to reddish brown. Female catkins about 35 mm long, red to reddish-brown, becoming dark brown to black and somewhat woody and cone-like in seed, 12-25 mm long. Individual flowers small, male flowers with 4 'petals', female flowers with 0 'petals'. Flowers autumn to winter.
Pest plant ACT.
PlantNET description: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Alnus~glutinosa (accessed 4 May 2021)
Detailed description in Wikipedia: https://en.wikipedia.org/wiki/Alnus_glutinosa (accessed 4 May 2021)
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