• Alnus P. Miller, 1754
• Alnus acuminata Kunth
• Alnus acutissima (H. Winkl.) Callier accepted as Alnus acuminata Kunth
• Alnus alisoviana Mandl accepted as Alnus incana (L.) Moench
• Alnus alnobetula (Ehrh.) K. Koch accepted as Alnus viridis (Chaix) DC.
• Alnus alnus (L.) Britton accepted as Alnus incana (L.) Moench
• Alnus alpina Vill. accepted as Alnus viridis (Chaix) DC.
• Alnus ambigua Beck accepted as Alnus pubescens Tausch
• Alnus americana (Regel) Czerep. accepted as Alnus incana (L.) Moench
• Alnus americana K. Koch accepted as Alnus serrulata (Aiton) Willd.
• Alnus arguta (Schltdl.) Spach accepted as Alnus acuminata Kunth
• Alnus aschersoniana Callier
• Alnus aurea K. Koch accepted as Alnus glutinosa (L.) Gaertn.
• Alnus autumnalis Hartig ex Garcke accepted as Alnus serrulata (Aiton) Willd.
• Alnus badensis Lange ex Regel accepted as Alnus pubescens Tausch
• Alnus balatonialis Borbás accepted as Alnus pubescens Tausch
• Alnus barbata C.A. Mey. accepted as Alnus glutinosa (L.) Gaertn.
• Alnus barbata Fr. ex Nyman accepted as Alnus pubescens Tausch
• Alnus beckii Callier accepted as Alnus pubescens Tausch
• Alnus borealis (Norrl.) C. Regel accepted as Alnus incana (L.) Moench
• Alnus borealis Koidz.
• Alnus brembana Rota accepted as Alnus viridis (Chaix) DC.
• Alnus californica (Regel) H. Winkl. accepted as Alnus rhombifolia Nutt.
• Alnus canadensis Lodd. ex Loudon accepted as Alnus incana (L.) Moench
• Alnus castaneifolia Mirb. accepted as Alnus acuminata Kunth
• Alnus cerifera Hartig ex Regel accepted as Alnus glutinosa (L.) Gaertn.
• Alnus communis Desf. ex Kuntze accepted as Alnus incana (L.) Moench
• Alnus cordata (Loisel.) Loisel.
• Alnus cordata Desf. accepted as Alnus cordata (Loisel.) Loisel.
• Alnus cordifolia Ten. accepted as Alnus cordata (Loisel.) Loisel.
• Alnus corylifolia A. Kern. ex Dalla Torre accepted as Alnus viridis (Chaix) DC.
• Alnus cremastogyne Burkill
• Alnus crispa (Aiton) Pursh accepted as Alnus viridis (Chaix) DC.
• Alnus cuneata Geyer ex Walp.
• Alnus cylindrostachya (H. Winkl.) Makino accepted as Alnus fauriei H. Lév. & Vaniot
• Alnus densiflora C.H. Mull. accepted as Alnus incana (L.) Moench
• Alnus denticulata C.A. Mey. accepted as Alnus glutinosa (L.) Gaertn.
• Alnus dimitrovii Jordanov & Kitanov
• Alnus dioica Roxb. accepted as Aporosa octandra (Buch.-Ham. ex D. Don) Vickery
• Alnus dubia Req. ex Regel accepted as Alnus glutinosa (L.) Gaertn.
• Alnus elliptica Req.
• Alnus emarginata (Matsum.) Shirai accepted as Alnus matsumurae Callier
• Alnus emarginata Krock. ex Steud. accepted as Alnus glutinosa (L.) Gaertn.
• Alnus fallacina Callier
• Alnus fauriei H. Lév. & Vaniot
• Alnus februaria Kuntze accepted as Alnus glutinosa (L.) Gaertn.
• Alnus fernandi-coburgii C.K. Schneid.
• Alnus ferruginea Kunth accepted as Alnus acuminata Kunth
• Alnus fiekii Callier
• Alnus figerti Callier
• Alnus firma Siebold & Zucc.
• Alnus firmifolia Fernald accepted as Alnus jorullensis Kunth
• Alnus formosana (Burkill) Makino
• Alnus fruticosa Rupr. accepted as Alnus viridis (Chaix) DC.
• Alnus gigantea Nakai
• Alnus glabrata Fernald accepted as Alnus acuminata Kunth
• Alnus glandulosa Sarg. accepted as Alnus viridis (Chaix) DC.
• Alnus glauca F. Michx. accepted as Alnus incana (L.) Moench
• Alnus glutinosa (L.) Gaertn.
• Alnus glutipes (Jarm. ex Czerpek) Vorosch.
• Alnus gracilis
• Alnus guatemalensis Gand. accepted as Alnus acuminata Kunth
• Alnus hakkodensis Hayashi
• Alnus hanedae Suyinata
• Alnus harinoki Siebold accepted as Alnus japonica (Thunb.) Steud.
• Alnus henedae Sugim.
• Alnus henryi C.K. Schneid.
• Alnus hirsuta (Spach) Rupr.
• Alnus hirtella (Franch. & Sav.) Koidz. accepted as Alnus firma Siebold & Zucc.
• Alnus hosoii Mizush.
• Alnus hybrida Rchb. accepted as Alnus pubescens Tausch
• Alnus imperialis Dippel accepted as Alnus glutinosa (L.) Gaertn.
• Alnus incana (L.) Moench
• Alnus incisa Steud. accepted as Alnus glutinosa (L.) Gaertn.
• Alnus inokumai Murai & Kusaka accepted as Alnus hirsuta (Spach) Rupr.
• Alnus integrifolia Roxb. ex Pax & K. Hoffm.
• Alnus integrifolia Roxb. ex Steud. accepted as Aporosa octandra (Buch.-Ham. ex D. Don) Vickery
• Alnus intermedia K. Koch accepted as Alnus elliptica Req.
• Alnus intermedia Schrad. ex Regel accepted as Alnus incana (L.) Moench
• Alnus jackii Hu accepted as Alnus trabeculosa Hand.-Mazz.
• Alnus japonica (Thunb.) Steud.
• Alnus japonica Siebold & Zucc. accepted as Alnus serrulatoides Callier
• Alnus jorullensis Benth. accepted as Alnus acuminata Kunth
• Alnus jorullensis Kunth
• Alnus kamschatica (Regel) Kudô ex Masam. accepted as Alnus viridis (Chaix) DC.
• Alnus katoana Yanagita
• Alnus koehnei Callier
• Alnus kolaensis Orlova accepted as Alnus incana (L.) Moench
• Alnus laciniata Ehrh. accepted as Alnus glutinosa (L.) Gaertn.
• Alnus lanata Duthie ex Bean
• Alnus lanceolata Phil. accepted as Alnus acuminata Kunth
• Alnus languinosa Gilib. accepted as Alnus incana (L.) Moench
• Alnus latifolia Desf. accepted as Alnus serrulata (Aiton) Willd.
• Alnus lindenii Regel accepted as Alnus acuminata Kunth
• Alnus lobata Nyman accepted as Alnus incana (L.) Moench
• Alnus longifolia Bové ex Spach accepted as Alnus orientalis Decne.
• Alnus macrocarpa Lodd. ex Loudon accepted as Alnus glutinosa (L.) Gaertn.
• Alnus macrocarpa Req. ex Nyman accepted as Alnus cordata (Loisel.) Loisel.
• Alnus macrophylla Desf. ex Steud. accepted as Alnus serrulata (Aiton) Willd.
• Alnus mairei H. Lév.