Alnus rubra
species of deciduous tree
Alnus rubra, the red alder,
is a deciduous broadleaf tree native to western North America (Alaska, Yukon, British Columbia, Washington, Oregon, California, Idaho and Montana).
Description
Alnus rubra is the largest species of alder in North America and one of the largest in the world, reaching heights of 20 to 30 metres (66 to 98 ft). The official tallest red alder (as of 1979) stands 32 m (105 ft) tall in Clatsop County, Oregon (US). The trunks range from 25 to 50 centimetres (10 to 19+1⁄2 in) in diameter. The bark is mottled, ashy-gray and smooth, often colonized by white lichen and moss. The leaves are ovate, 7 to 15 centimetres (2+3⁄4 to 6 in) long, with bluntly serrated edges and a distinct point at the end; the leaf margin is revolute, the very edge being curled under, a diagnostic character which distinguishes it from all other alders. Rather than turning yellow in autumn, its leaves darken in colour and wither before they are shed. The male flowers are dangling reddish catkins 10 to 15 cm (4 to 6 in) long in early spring. Female flowers occur in clusters of (3) 4–6 (8). Female catkins are erect during anthesis, but otherwise pendant.
This brief starts where responsible research should: with the source description of “Alnus rubra” as species of deciduous tree. Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the science & nature register because the source frames it as species of deciduous tree. Its deeper value depends on whether names, dates, institutions and citations support that framing.
Stable identifiers, scientific names and standards terminology offer the best bridge between this overview and specialist evidence. The source revision retrieved here is dated Aug 13, 2026. The linked authority identifier is Q1818806. The Library of Congress control number is sh85112026. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1979.
Current terminology should not be projected backward without checking the classification used when the underlying evidence was created. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Check terminology, classification and the date of the cited evidence. Scientific names and technical consensus can change while older records retain historical value.
- Current terminology
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Primary datasets, specimen catalogues, standards bodies and the most recent peer-reviewed literature.
Three-step research path
- Establish the record: confirm the title “Alnus rubra”, its source revision and the description used here.
- Expand the search: follow Alnus rubra primary sources, Alnus rubra archive and Alnus research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
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This entry incorporates text from “Alnus rubra” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.