| Common Name | Scientific Name | Code |
| n/a | Alnus ?fallacina Callier [incana ? serrulata] | ALFA4 |
| n/a | Alnus pendula Matsum. | ALPE10 |
| n/a | Alnus trabeculosa Hand.-Mazz. | ALTR12 |
| n/a | Betula ?alpestris Fr. | BEAL7 |
| n/a | Betula ?alpestris Fr. var. ?sukaczewii (Soczava) Govaerts | BEALS |
| n/a | Betula ?dugleana Lepage [nana ? neoalaskana] | BEDU |
| n/a | Betula ?eastwoodiae Sarg. (pro sp.) [nana ? occidentalis] | BEEA |
| n/a | Betula ?hornei Butler (pro sp.) [nana ? papyrifera] | BEHO |
| n/a | Betula ?jackii Schneid. [lenta ? pumila] | BEJA |
| n/a | Betula ?purpusii Schneid. [alleghaniensis ? pumila] | BEPU3 |
| n/a | Betula ?sandbergii Britt. [papyrifera ? pumila] | BESA |
| n/a | Betula ?sargentii Dugle [nana ? pumila] | BESA3 |
| n/a | Betula ?utahensis Britt. (pro sp.) [occidentalis ? papyrifera] | BEUT |
| n/a | Betula ?winteri Dugle [neoalaskana ? papyrifera] | BEWI2 |
| n/a | Betula nana L. ssp. exilis (Sukatschev) Hult | BENAE |
| n/a | Betula nana L. ssp. perfiljevii (V.N. Vassil) A.& D. L?ve | BENAP |
| n/a | Betula pendula Roth var. dalecarlica Schneid. [excluded] | BEPED |
| n/a | Betula platyphylla Sukatschev var. japonica (Miq.) Hara [excluded] | BEPLJ2 |
| n/a | Betula platyphylla Sukatschev var. kamtschatica (Regel) Hara [excluded] | BEPLK2 |
| alder | Alnus P. Mill. | ALNUS |
| Alnus glutinosa | Alnus alnus (L.) Britt. | ALAL7 |
| Alnus incana ssp. rugosa | Alnus incana (L.) Moench var. americana Regel | ALINA |
| Alnus incana ssp. rugosa | Alnus rugosa (Du Roi) Spreng. | ALRU3 |
| Alnus incana ssp. rugosa | Alnus rugosa (Du Roi) Spreng. var. americana (Regel) Fern. | ALRUA |
| Alnus incana ssp. tenuifolia | Alnus ?purpusii Callier | ALPU5 |
| Alnus incana ssp. tenuifolia | Alnus incana (L.) Moench var. occidentalis (Dippel) C.L. Hitchc. | ALINO |
| Alnus incana ssp. tenuifolia | Alnus incana (L.) Moench var. virescens S. Wats. | ALINV |
| Alnus incana ssp. tenuifolia | Alnus tenuifolia Nutt. | ALTE2 |
| Alnus maritima | Alnus maritima (Marsh.) Muhl. ex Nutt. ssp. metoporina (Furlow) E. Murr. | ALMAM3 |
| Alnus maritima | Alnus maritima (Marsh.) Muhl. ex Nutt. var. metoporina (Furlow) E. Murr. | ALMAM4 |
| Alnus maritima | Alnus metoporina Furlow | ALME2 |
| Alnus maritima | Betula-Alnus maritima Marsh. | BEMA |
| Alnus rhombifolia | Alnus rhombifolia Nutt. var. bernardina Munz & Johnston | ALRHB |
| Alnus rubra | Alnus oregona Nutt. | ALOR |
| Alnus rubra | Alnus oregona Nutt. var. pinnatisecta Starker | ALORP |
| Alnus serrulata | Alnus incana (L.) Moench var. serrulata (Ait.) Boivin | ALINS |
| Alnus serrulata | Alnus noveboracensis Britt. | ALNO |
| Alnus serrulata | Alnus serrulata (Ait.) Willd. var. subelliptica Fern. | ALSES |
| Alnus viridis ssp. crispa | Alnus ?hultenii Murai p.p. | ALHU3 |
| Alnus viridis ssp. crispa | Alnus crispa (Ait.) Pursh | ALCR6 |
| Alnus viridis ssp. crispa | Alnus crispa (Ait.) Pursh var. elongata Raup | ALCRE |
| Alnus viridis ssp. crispa | Alnus crispa (Ait.) Pursh var. mollis (Fern.) Fern. | ALCRM |
| Alnus viridis ssp. crispa | Alnus viridis (Chaix) DC. var. crispa (Ait.) House | ALVIC2 |
| Alnus viridis ssp. crispa | Duschekia viridis (Vill.) Opiz p.p. | DUVI3 |
| Alnus viridis ssp. sinuata | Alnus alnobetula (Ehrh.) K. Koch p.p. | ALAL9 |
| Alnus viridis ssp. sinuata | Alnus crispa (Ait.) Pursh ssp. laciniata Hult | ALCRL |
| Alnus viridis ssp. sinuata | Alnus crispa (Ait.) Pursh ssp. sinuata (Regel) Hult | ALCRS |
| Alnus viridis ssp. sinuata | Alnus sinuata (Regel) Rydb. | ALSI3 |
| Alnus viridis ssp. sinuata | Alnus viridis (Chaix) DC. var. sinuata Regel | ALVIS2 |
| Alnus viridis ssp. sinuata | Duschekia sinuata (Regel) Pouzar | DUSI |
| American hazelnut | Corylus americana Walt. | COAM3 |
| American hornbeam | Carpinus caroliniana Walt. | CACA18 |
| American hornbeam | Carpinus caroliniana Walt. ssp. caroliniana | CACAC2 |
| American hornbeam | Carpinus caroliniana Walt. ssp. virginiana (Marsh.) Furlow | CACAV |
| Arizona alder | Alnus oblongifolia Torr. | ALOB2 |
| Asian white birch | Betula platyphylla Sukatschev | BEPL2 |
| Asian white birch | Betula platyphylla Sukatschev var. platyphylla | BEPLP |
| beaked hazelnut | Corylus cornuta Marsh. | COCO6 |
| beaked hazelnut | Corylus cornuta Marsh. var. cornuta | COCOC2 |
| Betula ?alpestris var. ?sukaczewii | Betula ?sukaczewii Soczava | BESU3 |
| Betula ?caerulea var. grandis | Betula ?caerulea-grandis Blanch. | BECA8 |
| Betula ?eastwoodiae | Betula ?arbuscula Dugle | BEAR2 |
| Betula ?hornei | Betula ?ungavensis Lepage | BEUN |
| Betula ?utahensis | Betula ?commixta Sarg. | BECO4 |
| Betula ?utahensis | Betula andrewsii A. Nels. | BEAN |
| Betula ?utahensis | Betula occidentalis Hook. var. fecunda Fern. | BEOCF2 |
| Betula ?utahensis | Betula papyrifera Marsh. var. subcordata (Rydb.) Sarg. | BEPAS |
| Betula ?utahensis | Betula piperi Britt. | BEPI3 |
| Betula alleghaniensis var. alleghaniensis | Betula alleghaniensis Britt. var. fallax (Fassett) Brayshaw | BEALF |
| Betula alleghaniensis var. alleghaniensis | Betula lutea Michx. f. | BELU |
| Betula alleghaniensis var. alleghaniensis | Betula lutea Michx. f. var. fallax Fassett | BELUF |
| Betula alleghaniensis var. macrolepis | Betula lutea Michx. f. var. macrolepis Fern. | BELUM |
| Betula borealis | Betula pubescens Ehrh. ssp. borealis (Spach) A.& D. L?ve | BEPUB |
| Betula minor | Betula papyrifera Marsh. var. minor (Tuckerman) S. Wats. & Coult. | BEPAM |
| Betula minor | Betula saxophila Lepage | BESA4 |
| Betula nana ssp. exilis | Betula exilis Sukatschev | BEEX |
| Betula nana ssp. exilis | Betula glandulosa Michx. var. sibirica (Ledeb.) Schneid. | BEGLS |
| Betula nana ssp. exilis | Betula nana L. var. sibirica Ledeb. | BENAS |
| Betula nana ssp. perfiljevii | Betula perfiljevii V.N. Vassil | BEPE4 |
| Betula neoalaskana | Betula alaskana Sarg. | BEAL5 |
| Betula neoalaskana | Betula papyrifera Marsh. ssp. humilis (Regel) Hult | BEPAH |
| Betula neoalaskana | Betula papyrifera Marsh. var. humilis (Regel) Fern. & Raup | BEPAH2 |
| Betula neoalaskana | Betula papyrifera Marsh. var. neoalaskana (Sarg.) Raup | BEPAN |
| Betula neoalaskana | Betula resinifera Britt. | BERE3 |
| Betula occidentalis | Betula beeniana A. Nels. | BEBE3 |
| Betula occidentalis | Betula fontinalis Sarg. | BEFO2 |
| Betula occidentalis | Betula occidentalis Hook. var. inopina (Jepson) C.L. Hitchc. | BEOCI |
| Betula occidentalis | Betula papyrifera Marsh. ssp. occidentalis (Hook.) Hult | BEPAO |
| Betula occidentalis | Betula papyrifera Marsh. var. occidentalis (Hook.) Sarg. | BEPAO2 |
| Betula papyrifera var. cordifolia | Betula alba L. var. cordifolia (Regel) Regel | BEALC2 |
| Betula papyrifera var. cordifolia | Betula cordifolia Regel | BECO3 |
| Betula papyrifera var. kenaica | Betula kenaica W.H. Evans | BEKE2 |
| Betula papyrifera var. kenaica | Betula neoalaskana Sarg. var. kenaica (W.H. Evans) Boivin | BENEK |
| Betula papyrifera var. papyrifera | Betula alba L. var. commutata Regel | BEALC |
| Betula papyrifera var. papyrifera | Betula papyrifera Marsh. var. commutata (Regel) Fern. | BEPAC |
| Betula papyrifera var. papyrifera | Betula papyrifera Marsh. var. elobata (Fern.) Sarg. | BEPAE |
| Betula papyrifera var. papyrifera | Betula papyrifera Marsh. var. macrostachya Fern. | BEPAM2 |
| Betula papyrifera var. papyrifera | Betula papyrifera Marsh. var. pensilis Fern. | BEPAP2 |
| Betula pendula | Betula verrucosa Ehrh. | BEVE2 |
| Betula platyphylla var. japonica | Betula japonica (Miq.) Sieb. [excluded] | BEJA3 |
| Betula platyphylla var. japonica | Betula mandshurica (Regel) Nakai var. japonica (Miq.) Rehd. [excluded] | BEMAJ2 |
| Betula platyphylla var. kamtschatica | Betula kamtschatica (Regel) Jansson ex Vassiljev [excluded] | BEKA2 |
| Betula platyphylla var. kamtschatica | Betula mandshurica (Regel) Nakai var. kamtschatica (Regel) Rehd. [excluded] | BEMAK2 |
| Betula platyphylla var. platyphylla | Betula mandshurica (Regel) Nakai | BEMA2 |
| Betula pubescens var. pubescens | Betula alba L. | BEAL3 |
| Betula pumila var. glandulifera | Betula glandulifera (Regel) Butler | BEGL2 |
| Betula pumila var. glandulifera | Betula glandulosa Michx. var. glandulifera (Regel) Gleason | BEGLG |
| Betula pumila var. glandulifera | Betula glandulosa Michx. var. hallii (T.J. Howell) C.L. Hitchc. | BEGLH |
| Betula pumila var. glandulifera | Betula nana L. var. glandulifera (Regel) Boivin | BENAG |
| Betula pumila var. renifolia | Betula nana L. var. renifolia (Fern.) Boivin | BENAR |
| Betula szechuanica | Betula mandshurica (Regel) Nakai var. szechuanica (Schneid.) Rehd. | BEMAS |
| Betula szechuanica | Betula platyphylla Sukatschev var. szechuanica Schneid. | BEPLS |
| Betula uber | Betula lenta L. ssp. uber (Ashe) E. Murr. | BELEU2 |
| Betula uber | Betula lenta L. var. uber Ashe | BELEU |
| big blue birch | Betula ?caerulea Blanch. (pro sp.) var. grandis Blanch. (pro nm.) | BECAG |
| birch | Betula L. | BETUL |
| blue birch | Betula ?caerulea Blanch. (pro sp.) var. caerulea | BECAC |
| blue birch | Betula ?caerulea Blanch. (pro sp.) [papyrifera ? populifolia] | BECA4 |
| bog birch | Betula pumila L. | BEPU4 |
| bog birch | Betula pumila L. var. glabra Regel | BEPUG2 |
| bog birch | Betula pumila L. var. glandulifera Regel | BEPUG |
| bog birch | Betula pumila L. var. pumila | BEPUP2 |
| bog birch | Betula pumila L. var. renifolia Fern. | BEPUR |
| California hazelnut | Corylus cornuta Marsh. var. californica (A. DC.) Sharp | COCOC |
| Carpinus caroliniana ssp. caroliniana | Carpinus americana Michx. | CAAM21 |
| Carpinus caroliniana ssp. virginiana | Carpinus betulus L. var. virginiana Marsh. | CABEV |
| Carpinus caroliniana ssp. virginiana | Carpinus caroliniana Walt. var. virginiana (Marsh.) Fern. | CACAV2 |
| Chinese hazelnut | Corylus colurna L. var. chinensis (Franchet) Burkill | COCOC6 |
| Chisos hophornbeam | Ostrya virginiana (P. Mill.) K. Koch var. chisosensis (Correll) Henrickson, comb. nov. ined. | OSVIC |
| coigue | Nothofagus dombeyi (Mirb.) Blume | NODO |
| common filbert | Corylus avellana L. | COAV80 |
| Corylus americana | Corylus americana Walt. var. indehiscens Palmer & Steyermark | COAMI |
| Corylus colurna var. chinensis | Corylus chinensis Franchet | COCH7 |
| Corylus cornuta var. californica | Corylus californica (A. DC.) Rose | COCA23 |
| Corylus cornuta var. californica | Corylus cornuta Marsh. ssp. californica (A. DC.) E. Murr. | COCOC9 |
| Corylus cornuta var. californica | Corylus cornuta Marsh. var. glandulosa Boivin | COCOG2 |
| Corylus cornuta var. cornuta | Corylus rostrata Ait. | CORO5 |
| Corylus ferox var. thibetica | Corylus thibetica Batalin | COTH2 |
| downy birch | Betula pubescens Ehrh. | BEPU5 |
| downy birch | Betula pubescens Ehrh. var. pubescens | BEPUP4 |
| dwarf birch | Betula nana L. | BENA |
| dwarf white birch | Betula minor (Tuckerman) Fern. | BEMI |
| European alder | Alnus glutinosa (L.) Gaertn. | ALGL2 |
| European hornbeam | Carpinus betulus L. | CABE8 |
| European white birch | Betula pendula Roth | BEPE3 |
| giant filbert | Corylus maxima Miller | COMA18 |
| gray alder | Alnus incana (L.) Moench | ALIN2 |
| gray alder | Alnus incana (L.) Moench ssp. incana (L.) Moench [excluded] | ALINI2 |
| gray birch | Betula populifolia Marsh. | BEPO |
| green alder | Alnus viridis (Chaix) DC. | ALVI5 |
| hazel alder | Alnus serrulata (Ait.) Willd. | ALSE2 |
| hazelnut | Corylus L. | CORYL |
| Himalayan hazelnut | Corylus ferox Wallich | COFE5 |
| Himalayan hazelnut | Corylus ferox Wallich var. ferox | COFEF |
| hophornbeam | Ostrya virginiana (P. Mill.) K. Koch | OSVI |
| hophornbeam | Ostrya virginiana (P. Mill.) K. Koch var. virginiana | OSVIV |
| hophornbean | Ostrya Scop. | OSTRY |
| hornbeam | Carpinus L. | CARPI |
| Italian alder | Alnus cordata (Loisel.) Duby | ALCO13 |
| Japanese alder | Alnus japonica (Thunb.) Steud. | ALJA8 |
| Kenai birch | Betula papyrifera Marsh. var. kenaica (W.H. Evans) A. Henry | BEPAK |
| Knowlton's hophornbeam | Ostrya knowltonii Sarg. | OSKN |
| monarch birch | Betula maximowicziana Regel | BEMA5 |
| mountain alder | Alnus viridis (Chaix) DC. ssp. crispa (Ait.) Turrill | ALVIC |
| mountain paper birch | Betula papyrifera Marsh. var. cordifolia (Regel) Fern. | BEPAC2 |
| Murray's birch | Betula murrayana Barnes & Dancik | BEMU2 |
| Nepal alder | Alnus nepalensis D. Don | ALNE2 |
| northern birch | Betula borealis Spach | BEBO |
| Ostrya virginiana var. chisosensis | Ostrya chisosensis Correll | OSCH2 |
| Ostrya virginiana var. virginiana | Ostrya virginiana (P. Mill.) K. Koch var. lasia Fern. | OSVIL |
| paper birch | Betula papyrifera Marsh. | BEPA |
| paper birch | Betula papyrifera Marsh. var. papyrifera | BEPAP |
| red alder | Alnus rubra Bong. | ALRU2 |
| resin birch | Betula glandulosa Michx. | BEGL |
| resin birch | Betula neoalaskana Sarg. | BENE4 |
| river birch | Betula nigra L. | BENI |
| roble beech | Nothofagus obliqua (Birb.) Blume | NOOB |
| seaside alder | Alnus maritima (Marsh.) Muhl. ex Nutt. | ALMA7 |
| Siberian alder | Alnus viridis (Chaix) DC. ssp. fruticosa (Rupr.) Nyman | ALVIF |
| Siberian hazelnut | Corylus heterophylla Fisch. ex Trautv. | COHE12 |
| Sitka alder | Alnus viridis (Chaix) DC. ssp. sinuata (Regel) A.& D. L?ve | ALVIS |
| southern beech | Nothofagus Blume, nom. cons. | NOTHO7 |
| speckled alder | Alnus incana (L.) Moench ssp. rugosa (Du Roi) Clausen | ALINR |
| sweet birch | Betula lenta L. | BELE |
| Szechuan white birch | Betula szechuanica (Schneid.) C.A. Jansson | BESZ |
| thinleaf alder | Alnus incana (L.) Moench ssp. tenuifolia (Nutt.) Breitung | ALINT |
| Tibetan hazelnut | Corylus ferox Wallich var. thibetica (Batalin) Franchet | COFET |
| Turkish hazelnut | Corylus colurna L. | COCO30 |
| Turkish hazelnut | Corylus colurna L. var. colurna | COCOC5 |
| Virginia roundleaf birch | Betula uber (Ashe) Fern. | BEUB |
| water birch | Betula occidentalis Hook. | BEOC2 |
| white alder | Alnus rhombifolia Nutt. | ALRH2 |
| yellow birch | Betula alleghaniensis Britt. | BEAL2 |
| yellow birch | Betula alleghaniensis Britt. var. alleghaniensis | BEALA |
| yellow birch | Betula alleghaniensis Britt. var. macrolepis (Fern.) Brayshaw | BEALM |