Alnus serrulata(Aiton) Willd.

Brookside alderCommon alderHazel alderSmooth alderTag alderhazel alder

WFO wfo-0000947620 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Alnus serrulata, photographed by Joseph Aubert
fig. a Joseph Aubert, CC BY 4.0 / 2022-05-07 / obs. 196193313
Alnus serrulata, photographed by Bruce Slater
fig. b Bruce Slater, CC BY 4.0 / obs. 194175303
Alnus serrulata, photographed by ragbird
fig. c ragbird, CC0 1.0 / obs. 183486256
Alnus serrulata, photographed by Alan Weakley
fig. d Alan Weakley, CC0 1.0 / obs. 182844799
Alnus serrulata, photographed by Robert Harris
fig. e Robert Harris, CC BY 4.0 / obs. 181610032
Alnus serrulata, photographed by Leila Dasher
fig. f Leila Dasher, CC BY 4.0 / obs. 179344611
Alnus serrulata, photographed by Leila Dasher
fig. g Leila Dasher, CC BY 4.0 / obs. 179346702
Alnus serrulata, photographed by Michael J. Papay
fig. h Michael J. Papay, CC BY 4.0 / obs. 164447809

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 32 botanical countries

Regions where Alnus serrulata is native: Alabama, Arkansas, Connecticut, Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Mississippi, Missouri, New Hampshire, New Jersey, New York, North Carolina, Nova Scotia, Ohio, Oklahoma, Pennsylvania, Québec, Rhode I., South Carolina, Tennessee, Texas, Vermont, Virginia, West Virginia AlabamaArkansasConnecticutFloridaGeorgiaIllinoisIndianaKentuckyLouisianaMaineMarylandMassachusettsMississippiMissouriNew HampshireNew JerseyNew YorkNorth CarolinaNova ScotiaOhioOklahomaPennsylvaniaQuébecSouth CarolinaTennesseeTexasVermontVirginiaWest Virginia DelawareDistrict of ColumbiaRhode I.
Native distribution of Alnus serrulata, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows. Regions too small to draw at this scale are marked with a dot.
RegionTDWG codeContinent
Alabama ALA NORTHERN AMERICA
Arkansas ARK
Connecticut CNT
Delaware DEL
District of Columbia WDC
Florida FLA
Georgia GEO
Illinois ILL
Indiana INI
Kentucky KTY
Louisiana LOU
Maine MAI
Maryland MRY
Massachusetts MAS
Mississippi MSI
Missouri MSO
New Hampshire NWH
New Jersey NWJ
New York NWY
North Carolina NCA
Nova Scotia NSC
Ohio OHI
Oklahoma OKL
Pennsylvania PEN
Québec QUE
Rhode I. RHO
South Carolina SCA
Tennessee TEN
Texas TEX
Vermont VER
Virginia VRG
West Virginia WVA

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Flowering 81 in flower of 290 examined

Peak flowering in Feb. Each bar is the share of Alnus serrulata observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 81 of 290 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Also published as 31 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Alnus americana K.Koch
  • Alnus autumnalis Hartig ex Garcke
  • Alnus glutinosa lus. obtusifolia Regel
  • Alnus glutinosa prol. oblongata (Aiton) Rouy
  • Alnus glutinosa var. autumnalis Kuntze
  • Alnus glutinosa var. oblongata (Aiton) Pers.
  • Alnus glutinosa var. serrulata (Aiton) Regel
  • Alnus incana var. serrulata (Aiton) B.Boivin
  • Alnus latifolia Desf.
  • Alnus macrophylla Desf. ex Corrie
  • Alnus macrophylla Desf. ex Steud.
  • Alnus noveboracensis Britton
  • Alnus oblongata (Aiton) Willd.
  • Alnus oblongata var. elliptica Corrie
  • Alnus rubra Desf. ex Corrie
  • Alnus rubra Desf. ex Steud.
  • Alnus rugosa var. obtusifolia (Regel) H.J.P.Winkl.
  • Alnus rugosa var. serrulata (Aiton) H.J.P.Winkl.
  • Alnus serrulata f. emarginata Fernald
  • Alnus serrulata f. mollescens Fernald
  • Alnus serrulata f. nanella Fernald
  • Alnus serrulata f. noveboracensis (Britton) Fernald
  • Alnus serrulata f. serrulata
  • Alnus serrulata var. macrophylla Spach

and 7 more.

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.