| Rhododendron aberconwayi Cowan | | a | |
| Rhododendron adenogynum Diels | | a | |
| Rhododendron adenophorum Balf. f. & W. W. Sm. | Rhododendron adenogynum Diels | | i |
| Rhododendron aganniphum Balf. f. & Kingdon-Ward | | a | i |
| Rhododendron aganniphum Balf. f. & Kingdon-Ward var. aganniphum | | a | i |
| Rhododendron aganniphum Balf. f. & Kingdon-Ward var. flavorufum (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron agastum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron agetum Balf. f. & Forrest | Rhododendron neriiflorum Franch. subsp. agetum (Balf. f. & Forrest) Tagg | | i |
| Rhododendron agglutinatum Balf. f. & Forrest | Rhododendron phaeochrysum Balf. f. & W. W. Sm. var. agglutinatum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron aiolopeplum Balf. f. & Forrest | Rhododendron phaeochrysum Balf. f. & W. W. Sm. var. levistratum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron alabamense Rehder | | a | |
| Rhododendron albertsenianum Forrest | | a | |
| Rhododendron alutaceum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron alutaceum Balf. f. & W. W. Sm. var. alutaceum | | a | i |
| Rhododendron alutaceum Balf. f. & W. W. Sm. var. iodes (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron alutaceum Balf. f. & W. W. Sm. var. russotinctum (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron annae Franch. | | a | |
| Rhododendron anthosphaerum Diels | | a | |
| Rhododendron aperantum Balf. f. & Kingdon-Ward | | a | i |
| Rhododendron apodectum Balf. f. & W. W. Sm. | Rhododendron dichroanthum Diels subsp. apodectum (Balf. f. & W. W. Sm.) Cowan | | i |
| Rhododendron araiophyllum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron araliiforme Balf. f. & Forrest | Rhododendron vernicosum Franch. | | i |
| Rhododendron arborescens (Pursh) Torr. | | a | |
| Rhododendron arboreum Sm. | | a | |
| Rhododendron arboreum Sm. subsp. arboreum | | a | i |
| Rhododendron arboreum Sm. subsp. cinnamomeum (Lindl.) Tagg var. cinnamomeum Lindl. | | a | i |
| Rhododendron arboreum Sm. subsp. delavayi (Franch.) D. F. Chamb. | | a | i |
| Rhododendron arboreum Sm. subsp. nilagiricum (Zenker) Tagg | | a | i |
| Rhododendron arboreum Sm. subsp. zeylanicum (T. J. Booth) Tagg | | a | i |
| Rhododendron arboreum Sm. var. campbelliae (Hook. f.) C. B. Clarke | Rhododendron arboreum Sm. subsp. cinnamomeum (Lindl.) Tagg var. cinnamomeum Lindl. | | i |
| Rhododendron arboreum Sm. var. nilagiricum (Zenker) C. B. Clarke | Rhododendron arboreum Sm. subsp. nilagiricum (Zenker) Tagg | | i |
| Rhododendron argyrophyllum Franch. | | a | |
| Rhododendron argyrophyllum Franch. subsp. argyrophyllum | | a | i |
| Rhododendron argyrophyllum Franch. subsp. hypoglaucum (Hemsl.) D. F. Chamb. | | a | i |
| Rhododendron arizelum Balf. f. & Forrest | | a | i |
| Rhododendron atlanticum (Ashe) Rehder | | a | |
| Rhododendron aucklandii Hook. f. | Rhododendron griffithianum Wight | | i |
| Rhododendron aureum Georgi | | a | |
| Rhododendron auriculatum Hemsl. | | a | |
| Rhododendron austrinum (Small) Rehder | | a | |
| Rhododendron azaleoides hort. ex Dum. Cours. | Rhododendron ponticum L. | | |
| Rhododendron bainbridgeanum Tagg & Forrest | | a | |
| Rhododendron balfourianum Diels | | a | |
| Rhododendron balfourianum Diels var. aganniphoides Tagg & Forrest | Rhododendron balfourianum Diels | | i |
| Rhododendron barbatum Wall. ex G. Don | | a | |
| Rhododendron basilicum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron beesianum Diels | | a | |
| Rhododendron beimaense Balf. f. & Forrest | Rhododendron erythrocalyx Balf. f. & Forrest | | i |
| Rhododendron brachyandrum Balf. f. & Forrest | Rhododendron eclecteum Balf. f. & Forrest var. eclecteum | | i |
| Rhododendron brachycarpum D. Don ex G. Don | | a | |
| Rhododendron brachycarpum D. Don ex G. Don subsp. fauriei (Franch.) D. F. Chamb. | Rhododendron brachycarpum D. Don ex G. Don | | i |
| Rhododendron brachycarpum D. Don ex G. Don subsp. tigerstedtii Nitz. | Rhododendron brachycarpum D. Don ex G. Don | | i |
| Rhododendron brachycarpum D. Don ex G. Don var. lutescens Koidz. | Rhododendron nikomontanum (Komatsu) Nakai | | i |
| Rhododendron brunneifolium Balf. f. & Forrest | Rhododendron eudoxum Balf. f. & Forrest var. brunneifolium (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron bureavii Franch. | | a | |
| Rhododendron calendulaceum (Michx.) Torr. | | a | |
| Rhododendron californicum Hook. | Rhododendron macrophyllum D. Don ex G. Don | | |
| Rhododendron callimorphum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron callimorphum Balf. f. & W. W. Sm. var. callimorphum | | a | i |
| Rhododendron callimorphum Balf. f. & W. W. Sm. var. myiagrum (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron calophytum Franch. | | a | |
| Rhododendron caloxanthum Balf. f. & Farrer | Rhododendron campylocarpum Hook. f. subsp. caloxanthum (Balf. f. & Farrer) D. F. Chamb. | | i |
| Rhododendron campanulatum D. Don | | a | |
| Rhododendron campanulatum D. Don var. wallichii (Hook. f.) Hook. f. | Rhododendron wallichii Hook. f. | | i |
| Rhododendron campbelliae Hook. f. | Rhododendron arboreum Sm. subsp. cinnamomeum (Lindl.) Tagg var. cinnamomeum Lindl. | | i |
| Rhododendron campylocarpum Hook. f. | | a | i |
| Rhododendron campylocarpum Hook. f. subsp. caloxanthum (Balf. f. & Farrer) D. F. Chamb. | | a | i |
| Rhododendron campylocarpum Hook. f. subsp. campylocarpum | | a | i |
| Rhododendron canadense (L.) Torr. | | a | |
| Rhododendron canescens (Michx.) Sweet | | a | |
| Rhododendron canescens (Michx.) Sweet var. candidum (Small) Rehder | Rhododendron canescens (Michx.) Sweet | | i |
| Rhododendron catacosmum Balf. f. ex Tagg | | a | i |
| Rhododendron catawbiense Michx. | | a | |
| Rhododendron caucasicum Pall. | | a | |
| Rhododendron cerasinum Tagg | | a | |
| Rhododendron chaetomallum Balf. f. & Forrest | Rhododendron haematodes Franch. subsp. chaetomallum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron chalarocladum Balf. f. & Forrest | Rhododendron selense Franch. subsp. selense | | i |
| Rhododendron chamaethomsonii (Tagg) Cowan & Davidian | | a | |
| Rhododendron chamaethomsonii (Tagg) Cowan & Davidian var. chamaedoron (Tagg) D. F. Chamb. | | a | i |
| Rhododendron chamaethomsonii (Tagg) Cowan & Davidian var. chamaethauma (Tagg) Cowan & Davidian | | a | i |
| Rhododendron chamaethomsonii (Tagg) Cowan & Davidian var. chamaethomsonii | | a | i |
| Rhododendron chrysanthum Pall. | Rhododendron aureum Georgi | | |
| Rhododendron chrysanthum Pall. var. nikomontanum Komatsu | Rhododendron nikomontanum (Komatsu) Nakai | | i |
| Rhododendron citriniflorum Balf. f. & Forrest | | a | i |
| Rhododendron citriniflorum Balf. f. & Forrest var. citriniflorum | | a | i |
| Rhododendron citriniflorum Balf. f. & Forrest var. horaeum (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron clementinae Forrest | | a | |
| Rhododendron cloiophorum Balf. f. & Forrest | Rhododendron sanguineum Franch. var. cloiophorum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron colletum Balf. f. & Forrest | Rhododendron beesianum Diels | | i |
| Rhododendron coriaceum Franch. | | a | |
| Rhododendron coryanum Tagg & Forrest | | a | |
| Rhododendron coryphaeum Balf. f. & Forrest | Rhododendron praestans Balf. f. & W. W. Sm. | | i |
| Rhododendron crinigerum Franch. | | a | |
| Rhododendron croceum Balf. f. & W. W. Sm. | Rhododendron wardii W. W. Sm. var. wardii | | i |
| Rhododendron cucullatum Hand.-Mazz. | Rhododendron roxieanum Forrest var. cucullatum (Hand.-Mazz.) D. F. Chamb. | | |
| Rhododendron cumberlandense E. L. Braun | | a | |
| Rhododendron dasycladum Balf. f. & W. W. Sm. | Rhododendron selense Franch. subsp. dasycladum (Balf. f. & W. W. Sm.) D. F. Chamb. | | i |
| Rhododendron decorum Franch. | | a | |
| Rhododendron decorum Franch. subsp. decorum | | a | i |
| Rhododendron decorum Franch. subsp. diaprepes (Balf. f. & W. W. Sm.) T. L. Ming | | a | i |
| Rhododendron degronianum Carriere | | a | |
| Rhododendron degronianum Carriere subsp. degronianum | | a | i |
| Rhododendron degronianum Carriere subsp. heptamerum (Maxim.) H. Hara | | a | i |
| Rhododendron degronianum Carriere subsp. heptamerum (Maxim.) H. Hara var. heptamerum (Maxim.) Sealy ex Davidian | | a | i |
| Rhododendron degronianum Carriere subsp. heptamerum (Maxim.) H. Hara var. hondoense (Nakai) H. Hara | | a | i |
| Rhododendron degronianum Carriere subsp. heptamerum (Maxim.) H. Hara var. kyomaruense (T. Yamaz.) H. Hara | | a | i |
| Rhododendron degronianum Carriere subsp. yakushimanum (Nakai) H. Hara | | a | i |
| Rhododendron degronianum Carriere subsp. yakushimanum (Nakai) H. Hara var. intermedium (Sugim.) H. Hara | | a | i |
| Rhododendron degronianum Carriere subsp. yakushimanum (Nakai) H. Hara var. yakushimanum (Nakai) Kitam. | | a | i |
| Rhododendron delavayi Franch. | Rhododendron arboreum Sm. subsp. delavayi (Franch.) D. F. Chamb. | | |
| Rhododendron diaprepes Balf. f. & W. W. Sm. | Rhododendron decorum Franch. subsp. diaprepes (Balf. f. & W. W. Sm.) T. L. Ming | | i |
| Rhododendron dichroanthum Diels | | a | |
| Rhododendron dichroanthum Diels subsp. apodectum (Balf. f. & W. W. Sm.) Cowan | | a | i |
| Rhododendron dichroanthum Diels subsp. dichroanthum | | a | i |
| Rhododendron dichroanthum Diels subsp. scyphocalyx (Balf. f. & Forrest) Cowan | | a | i |
| Rhododendron dichroanthum Diels subsp. septentrionale Cowan | | a | i |
| Rhododendron dictyotum Balf. f. ex Tagg | Rhododendron traillianum Forrest & W. W. Sm. var. dictyotum (Balf. f. ex Tagg) D. F. Chamb. | | i |
| Rhododendron didymum Balf. f. & Forrest | Rhododendron sanguineum Franch. var. didymum (Balf. f. & Forrest) T. L. Ming | | i |
| Rhododendron discolor Franch. | Rhododendron fortunei Lindl. subsp. discolor (Franch.) D. F. Chamb. | | |
| Rhododendron dryophyllum Balf. f. & Forrest | Rhododendron phaeochrysum Balf. f. & W. W. Sm. var. phaeochrysum | | i |
| Rhododendron dumosulum Balf. f. & Forrest | Rhododendron phaeochrysum Balf. f. & W. W. Sm. var. agglutinatum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron eclecteum Balf. f. & Forrest | | a | i |
| Rhododendron eclecteum Balf. f. & Forrest var. bellatulum Tagg | | a | i |
| Rhododendron eclecteum Balf. f. & Forrest var. brachyandrum (Balf. f. & Forrest) Cowan & Davidian | Rhododendron eclecteum Balf. f. & Forrest var. eclecteum | | i |
| Rhododendron eclecteum Balf. f. & Forrest var. eclecteum | | a | i |
| Rhododendron elliottii G. Watt | | a | |
| Rhododendron erastum Balf. f. & Forrest | | a | i |
| Rhododendron eriogynum Balf. f. & W. W. Sm. | Rhododendron facetum Balf. f. & Kingdon-Ward | | i |
| Rhododendron eritimum Balf. f. & W. W. Sm. | Rhododendron anthosphaerum Diels | | i |
| Rhododendron erythrocalyx Balf. f. & Forrest | | a | i |
| Rhododendron euchaites Balf. f. & Forrest | Rhododendron neriiflorum Franch. subsp. neriiflorum | | i |
| Rhododendron eudoxum Balf. f. & Forrest | | a | i |
| Rhododendron eudoxum Balf. f. & Forrest var. brunneifolium (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron eudoxum Balf. f. & Forrest var. eudoxum | | a | i |
| Rhododendron eudoxum Balf. f. & Forrest var. mesopolium (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron exasperatum Tagg | | a | |
| Rhododendron eximium Nutt. | Rhododendron falconeri Hook. f. subsp. eximium (Nutt.) D. F. Chamb. | | |
| Rhododendron facetum Balf. f. & Kingdon-Ward | | a | i |
| Rhododendron falconeri Hook. f. | | a | i |
| Rhododendron falconeri Hook. f. subsp. eximium (Nutt.) D. F. Chamb. | | a | i |
| Rhododendron falconeri Hook. f. subsp. falconeri | | a | i |
| Rhododendron fargesii Franch. | Rhododendron oreodoxa Franch. var. fargesii (Franch.) D. F. Chamb. | | |
| Rhododendron fauriei Franch. | Rhododendron brachycarpum D. Don ex G. Don | | |
| Rhododendron fictolacteum Balf. f. | Rhododendron rex H. Lev. subsp. fictolacteum (Balf. f.) D. F. Chamb. | | i |
| Rhododendron flammeum (Michx.) Sarg. | | a | |
| Rhododendron flavorufum Balf. f. & Forrest | Rhododendron aganniphum Balf. f. & Kingdon-Ward var. flavorufum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron flavum G. Don | Rhododendron luteum Sweet | | |
| Rhododendron floccigerum Franch. | | a | |
| Rhododendron formosanum Hemsl. | | a | |
| Rhododendron forrestii Balf. f. ex Diels | | a | i |
| Rhododendron forrestii Balf. f. ex Diels subsp. forrestii | | a | i |
| Rhododendron forrestii Balf. f. ex Diels subsp. papillatum D. F. Chamb. | | a | i |
| Rhododendron fortunei Lindl. | | a | |
| Rhododendron fortunei Lindl. subsp. discolor (Franch.) D. F. Chamb. | | a | i |
| Rhododendron fortunei Lindl. subsp. fortunei | | a | i |
| Rhododendron fulgens Hook. f. | | a | i |
| Rhododendron fulvastrum Balf. f. & Forrest | | a | i |
| Rhododendron fulvoides Balf. f. & Forrest | Rhododendron fulvum Balf. f. & W. W. Sm. | | i |
| Rhododendron fulvum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron galactinum Balf. f. ex Tagg | | a | i |
| Rhododendron giganteum Tagg | Rhododendron protistum Balf. f. & Forrest var. giganteum (Tagg) D. F. Chamb. | | |
| Rhododendron glischrum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron globigerum Balf. f. & Forrest | Rhododendron alutaceum Balf. f. & W. W. Sm. var. alutaceum | | i |
| Rhododendron grande Wight | | a | |
| Rhododendron griersonianum Balf. f. & Forrest | | a | i |
| Rhododendron griffithianum Wight | | a | |
| Rhododendron gymnanthum Diels | Rhododendron lukiangense Franch. | | |
| Rhododendron gymnogynum Balf. f. & Forrest | Rhododendron anthosphaerum Diels | | i |
| Rhododendron habrotrichum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron haemaleum Balf. f. & Forrest | Rhododendron sanguineum Franch. var. haemaleum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron haematodes Franch. | | a | |
| Rhododendron haematodes Franch. subsp. chaetomallum (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron haematodes Franch. subsp. haematodes | | a | i |
| Rhododendron hardingii Forrest ex Tagg | Rhododendron annae Franch. | | |
| Rhododendron hemidartum Balf. f. ex Tagg | Rhododendron pocophorum Balf. f. ex Tagg var. hemidartum (Balf. f. ex Tagg) D. F. Chamb. | | i |
| Rhododendron heptamerum Balf. f. | Rhododendron anthosphaerum Diels | | i |
| Rhododendron himertum Balf. f. & Forrest | Rhododendron sanguineum Franch. var. himertum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron hirtipes Tagg | | a | |
| Rhododendron hodgsonii Hook. f. | | a | i |
| Rhododendron hookeri Nutt. | | a | |
| Rhododendron horaeum Balf. f. & Forrest | Rhododendron citriniflorum Balf. f. & Forrest var. horaeum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron houlstonii Hemsl. & E. H. Wilson | Rhododendron fortunei Lindl. subsp. discolor (Franch.) D. F. Chamb. | | |
| Rhododendron hylaeum Balf. f. & Farrer | | a | i |
| Rhododendron hylothreptum Balf. f. & W. W. Sm. | Rhododendron anthosphaerum Diels | | i |
| Rhododendron hymenanthes Makino | Rhododendron degronianum Carriere subsp. heptamerum (Maxim.) H. Hara var. heptamerum (Maxim.) Sealy ex Davidian | | |
| Rhododendron hyperythrum Hayata | | a | |
| Rhododendron hypoglaucum Hemsl. | Rhododendron argyrophyllum Franch. subsp. hypoglaucum (Hemsl.) D. F. Chamb. | | |
| Rhododendron insigne Hemsl. & E. H. Wilson | | a | |
| Rhododendron iodes Balf. f. & Forrest | Rhododendron alutaceum Balf. f. & W. W. Sm. var. iodes (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron irroratum Franch. | | a | |
| Rhododendron ixeuticum Balf. f. & W. W. Sm. | Rhododendron crinigerum Franch. | | i |
| Rhododendron japanoheptamerum Kitam. | Rhododendron degronianum Carriere subsp. heptamerum (Maxim.) H. Hara var. heptamerum (Maxim.) Sealy ex Davidian | | |
| Rhododendron japanoheptamerum Kitam. var. kyomaruense (T. Yamaz.) T. Yamaz. | Rhododendron degronianum Carriere subsp. heptamerum (Maxim.) H. Hara var. kyomaruense (T. Yamaz.) H. Hara | | i |
| Rhododendron japonicum (A. Gray) J. V. Suringar | Rhododendron molle (Blume) G. Don subsp. japonicum (A. Gray) Kron | | |
| Rhododendron japonicum (A. Gray) J. V. Suringar var. glaucophyllum H. Hara ex Ohwi, nom. inval. | Rhododendron molle (Blume) G. Don subsp. japonicum (A. Gray) Kron | | i |
| Rhododendron japonicum (Blume) C. K. Schneid. | Rhododendron degronianum Carriere subsp. heptamerum (Maxim.) H. Hara var. heptamerum (Maxim.) Sealy ex Davidian | | |
| Rhododendron jucundum Balf. f. & W. W. Sm. | Rhododendron selense Franch. subsp. jucundum (Balf. f. & W. W. Sm.) D. F. Chamb. | | i |
| Rhododendron kosterianum C. K. Schneid. | | a | |
| Rhododendron kyawi Lace & W. W. Sm. | | a | |
| Rhododendron lacteum Franch. | | a | |
| Rhododendron lanatum Hook. f. | | a | i |
| Rhododendron lanigerum Tagg | | a | |
| Rhododendron levistratum Balf. f. & Forrest | Rhododendron phaeochrysum Balf. f. & W. W. Sm. var. levistratum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron litiense Balf. f. & Forrest | Rhododendron wardii W. W. Sm. var. wardii | | i |
| Rhododendron lucidum Franch. | Rhododendron vernicosum Franch. | | |
| Rhododendron lukiangense Franch. | | a | |
| Rhododendron luteum Sweet | | a | |
| Rhododendron macabeanum G. Watt ex Balf. f. | | a | i |
| Rhododendron macrophyllum D. Don ex G. Don | | a | |
| Rhododendron magnificum Kingdon-Ward | | a | |
| Rhododendron makinoi Tagg ex Nakai | | a | |
| Rhododendron martinianum Balf. f. & Forrest | | a | i |
| Rhododendron maximum L. | | a | |
| Rhododendron mesopolium Balf. f. & Forrest | Rhododendron eudoxum Balf. f. & Forrest var. mesopolium (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron metternichii Siebold & Zucc. | Rhododendron degronianum Carriere subsp. heptamerum (Maxim.) H. Hara var. heptamerum (Maxim.) Sealy ex Davidian | | |
| Rhododendron metternichii Siebold & Zucc. subsp. pentamerum (Maxim.) Sugim. | Rhododendron degronianum Carriere subsp. degronianum | | i |
| Rhododendron metternichii Siebold & Zucc. subsp. yakushimanum (Nakai) Sugim. | Rhododendron degronianum Carriere subsp. yakushimanum (Nakai) H. Hara var. yakushimanum (Nakai) Kitam. | | i |
| Rhododendron metternichii Siebold & Zucc. var. heptamerum Maxim. | Rhododendron degronianum Carriere subsp. heptamerum (Maxim.) H. Hara var. heptamerum (Maxim.) Sealy ex Davidian | | i |
| Rhododendron metternichii Siebold & Zucc. var. hondoense Nakai | Rhododendron degronianum Carriere subsp. heptamerum (Maxim.) H. Hara var. hondoense (Nakai) H. Hara | | i |
| Rhododendron metternichii Siebold & Zucc. var. intermedium Sugim. | Rhododendron degronianum Carriere subsp. yakushimanum (Nakai) H. Hara var. intermedium (Sugim.) H. Hara | | i |
| Rhododendron metternichii Siebold & Zucc. var. kyomaruense T. Yamaz. | Rhododendron degronianum Carriere subsp. heptamerum (Maxim.) H. Hara var. kyomaruense (T. Yamaz.) H. Hara | | i |
| Rhododendron metternichii Siebold & Zucc. var. pentamerum Maxim. | Rhododendron degronianum Carriere subsp. degronianum | | i |
| Rhododendron metternichii Siebold & Zucc. var. yakushimanum (Nakai) Ohwi | Rhododendron degronianum Carriere subsp. yakushimanum (Nakai) H. Hara var. yakushimanum (Nakai) Kitam. | | i |
| Rhododendron mimetes Tagg & Forrest | | a | |
| Rhododendron mimetes Tagg & Forrest var. simulans Tagg & Forrest | | a | i |
| Rhododendron molle (Blume) G. Don | | a | |
| Rhododendron molle (Blume) G. Don subsp. japonicum (A. Gray) Kron | | a | i |
| Rhododendron molle (Blume) G. Don subsp. molle | | a | i |
| Rhododendron morii Hayata | | a | |
| Rhododendron myiagrum Balf. f. & Forrest | Rhododendron callimorphum Balf. f. & W. W. Sm. var. myiagrum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron neriiflorum Franch. | | a | |
| Rhododendron neriiflorum Franch. subsp. agetum (Balf. f. & Forrest) Tagg | | a | i |
| Rhododendron neriiflorum Franch. subsp. neriiflorum | | a | i |
| Rhododendron neriiflorum Franch. subsp. phaedropum (Balf. f. & Farrer) Tagg | | a | i |
| Rhododendron nikomontanum (Komatsu) Nakai | | a | |
| Rhododendron nilagiricum Zenker | Rhododendron arboreum Sm. subsp. nilagiricum (Zenker) Tagg | | |
| Rhododendron niphargum Balf. f. & Kingdon-Ward | Rhododendron uvarifolium Diels | | i |
| Rhododendron niveum Hook. f. | | a | i |
| Rhododendron nudiflorum Torr. | Rhododendron periclymenoides (Michx.) Shinners | | |
| Rhododendron nudiflorum Torr. f. glandiferum (Porter) Fernald | Rhododendron periclymenoides (Michx.) Shinners | | i |
| Rhododendron oblongifolium (Small) Millais | Rhododendron viscosum (L.) Torr. | | |
| Rhododendron occidentale (Torr. & A. Gray) A. Gray | | a | |
| Rhododendron orbiculare Decne. | | a | |
| Rhododendron oreodoxa Franch. | | a | |
| Rhododendron oreodoxa Franch. var. fargesii (Franch.) D. F. Chamb. | | a | i |
| Rhododendron oreodoxa Franch. var. oreodoxa | | a | i |
| Rhododendron pagophilum Balf. f. & Kingdon-Ward | Rhododendron selense Franch. subsp. selense | | i |
| Rhododendron periclymenoides (Michx.) Shinners | | a | |
| Rhododendron phaedropum Balf. f. & Farrer | Rhododendron neriiflorum Franch. subsp. phaedropum (Balf. f. & Farrer) Tagg | | i |
| Rhododendron phaeochrysum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron phaeochrysum Balf. f. & W. W. Sm. var. agglutinatum (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron phaeochrysum Balf. f. & W. W. Sm. var. levistratum (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron phaeochrysum Balf. f. & W. W. Sm. var. phaeochrysum | | a | i |
| Rhododendron planetum Balf. f. | | a | i |
| Rhododendron pocophorum Balf. f. ex Tagg | | a | i |
| Rhododendron pocophorum Balf. f. ex Tagg var. hemidartum (Balf. f. ex Tagg) D. F. Chamb. | | a | i |
| Rhododendron pocophorum Balf. f. ex Tagg var. pocophorum | | a | i |
| Rhododendron poecilodermum Balf. f. & Forrest | Rhododendron roxieanum Forrest var. roxieanum | | i |
| Rhododendron ponticum L. | | a | |
| Rhododendron praestans Balf. f. & W. W. Sm. | | a | i |
| Rhododendron praevernum Hutch. | | a | |
| Rhododendron prinophyllum (Small) Millais | | a | |
| Rhododendron probum Balf. f. & Forrest | Rhododendron selense Franch. subsp. selense | | i |
| Rhododendron pronum Tagg & Forrest | | a | |
| Rhododendron proteoides Balf. f. & W. W. Sm. | | a | i |
| Rhododendron protistum Balf. f. & Forrest | | a | i |
| Rhododendron protistum Balf. f. & Forrest var. giganteum (Tagg) D. F. Chamb. | | a | i |
| Rhododendron protistum Balf. f. & Forrest var. protistum | | a | i |
| Rhododendron prunifolium (Small) Millais | | a | |
| Rhododendron przewalskii Maxim. | | a | |
| Rhododendron pseudochrysanthum Hayata | | a | |
| Rhododendron puralbum Balf. f. & W. W. Sm. | Rhododendron wardii W. W. Sm. var. puralbum (Balf. f. & W. W. Sm.) D. F. Chamb. | | i |
| Rhododendron purdomii Rehder & E. H. Wilson | | a | |
| Rhododendron recurvoides Tagg & Kingdon-Ward | | a | |
| Rhododendron recurvum Balf. f. & Forrest | Rhododendron roxieanum Forrest var. roxieanum | | i |
| Rhododendron recurvum Balf. f. & Forrest var. oreonastes Balf. f. & Forrest | Rhododendron roxieanum Forrest var. oreonastes (Balf. f. & Forrest) T. L. Ming | | i |
| Rhododendron repens Balf. f. & Forrest | Rhododendron forrestii Balf. f. ex Diels subsp. forrestii | | i |
| Rhododendron repens Balf. f. & Forrest var. chamaedoron Tagg | Rhododendron chamaethomsonii (Tagg) Cowan & Davidian var. chamaedoron (Tagg) D. F. Chamb. | | i |
| Rhododendron repens Balf. f. & Forrest var. chamaethauma Tagg | Rhododendron chamaethomsonii (Tagg) Cowan & Davidian var. chamaethauma (Tagg) Cowan & Davidian | | i |
| Rhododendron repens Balf. f. & Forrest var. chamaethomsonii Tagg | Rhododendron chamaethomsonii (Tagg) Cowan & Davidian var. chamaethomsonii | | i |
| Rhododendron rex H. Lev. | | a | |
| Rhododendron rex H. Lev. subsp. fictolacteum (Balf. f.) D. F. Chamb. | | a | i |
| Rhododendron rex H. Lev. subsp. rex | | a | i |
| Rhododendron rhaibocarpum Balf. f. & W. W. Sm. | Rhododendron selense Franch. subsp. dasycladum (Balf. f. & W. W. Sm.) D. F. Chamb. | | i |
| Rhododendron roseum auct. | Rhododendron prinophyllum (Small) Millais | | |
| Rhododendron roseum Rehder | Rhododendron canescens (Michx.) Sweet | | |
| Rhododendron roxieanum Forrest | | a | |
| Rhododendron roxieanum Forrest var. cucullatum (Hand.-Mazz.) D. F. Chamb. | | a | i |
| Rhododendron roxieanum Forrest var. oreonastes (Balf. f. & Forrest) T. L. Ming | | a | i |
| Rhododendron roxieanum Forrest var. roxieanum | | a | i |
| Rhododendron rufum Batalin | | a | |
| Rhododendron russotinctum Balf. f. & Forrest | Rhododendron alutaceum Balf. f. & W. W. Sm. var. russotinctum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron sanguineum Franch. | | a | |
| Rhododendron sanguineum Franch. subsp. melleum Cowan | Rhododendron sanguineum Franch. var. himertum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron sanguineum Franch. var. cloiophorum (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron sanguineum Franch. var. didymoides Tagg | | a | i |
| Rhododendron sanguineum Franch. var. didymum (Balf. f. & Forrest) T. L. Ming | | a | i |
| Rhododendron sanguineum Franch. var. haemaleum (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron sanguineum Franch. var. himertum (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron sanguineum Franch. var. sanguineum | | a | i |
| Rhododendron schizopeplum Balf. f. & Forrest | Rhododendron aganniphum Balf. f. & Kingdon-Ward var. aganniphum | | i |
| Rhododendron scyphocalyx Balf. f. & Forrest | Rhododendron dichroanthum Diels subsp. scyphocalyx (Balf. f. & Forrest) Cowan | | i |
| Rhododendron selense Franch. | | a | |
| Rhododendron selense Franch. subsp. dasycladum (Balf. f. & W. W. Sm.) D. F. Chamb. | | a | i |
| Rhododendron selense Franch. subsp. jucundum (Balf. f. & W. W. Sm.) D. F. Chamb. | | a | i |
| Rhododendron selense Franch. subsp. selense | | a | i |
| Rhododendron selense Franch. subsp. setiferum (Balf. f. & Forrest) D. F. Chamb. | | a | i |
| Rhododendron serpens Balf. f. & Forrest | Rhododendron erastum Balf. f. & Forrest | | i |
| Rhododendron setiferum Balf. f. & Forrest | Rhododendron selense Franch. subsp. setiferum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron sidereum Balf. f. | | a | i |
| Rhododendron sigillatum Balf. f. & Forrest | Rhododendron phaeochrysum Balf. f. & W. W. Sm. var. levistratum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron simiarum Hance | | a | |
| Rhododendron simulans (Tagg & Forrest) D. F. Chamb. | Rhododendron mimetes Tagg & Forrest var. simulans Tagg & Forrest | | |
| Rhododendron sinogrande Balf. f. & W. W. Sm. | | a | i |
| Rhododendron smirnowii Trautv. | | a | |
| Rhododendron smithii Sweet | | a | |
| Rhododendron souliei Franch. | | a | |
| Rhododendron sperabile Balf. f. & Farrer | | a | i |
| Rhododendron sphaeroblastum Balf. f. & Forrest | | a | i |
| Rhododendron stewartianum Diels | | a | |
| Rhododendron strigillosum Franch. | | a | |
| Rhododendron sutchuenense Franch. | | a | |
| Rhododendron taliense Franch. | | a | |
| Rhododendron tanastylum Balf. f. & Kingdon-Ward | | a | i |
| Rhododendron telopeum Balf. f. & Forrest | Rhododendron campylocarpum Hook. f. subsp. caloxanthum (Balf. f. & Farrer) D. F. Chamb. | | i |
| Rhododendron temenium Balf. f. & Forrest | | a | i |
| Rhododendron thomsonii Hook. f. | | a | i |
| Rhododendron traillianum Forrest & W. W. Sm. | | a | |
| Rhododendron traillianum Forrest & W. W. Sm. var. dictyotum (Balf. f. ex Tagg) D. F. Chamb. | | a | i |
| Rhododendron traillianum Forrest & W. W. Sm. var. traillianum | | a | i |
| Rhododendron trichomiscum Balf. f. & Forrest | Rhododendron eudoxum Balf. f. & Forrest var. eudoxum | | i |
| Rhododendron triplonaevium Balf. f. & Forrest | Rhododendron alutaceum Balf. f. & W. W. Sm. var. russotinctum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron tritifolium Balf. f. & Forrest | Rhododendron alutaceum Balf. f. & W. W. Sm. var. russotinctum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron ungernii Trautv. | | a | |
| Rhododendron uvarifolium Diels | | a | |
| Rhododendron vernicosum Franch. | | a | |
| Rhododendron vesiculiferum Tagg | | a | |
| Rhododendron viscosum (L.) Torr. | | a | |
| Rhododendron viscosum (L.) Torr. f. rhodanthum Rehder | Rhododendron viscosum (L.) Torr. | | i |
| Rhododendron viscosum (L.) Torr. var. glaucum Torr. | Rhododendron viscosum (L.) Torr. | | i |
| Rhododendron viscosum (L.) Torr. var. nitidum (Pursh) A. Gray | Rhododendron viscosum (L.) Torr. | | i |
| Rhododendron wallichii Hook. f. | | a | i |
| Rhododendron wardii W. W. Sm. | | a | |
| Rhododendron wardii W. W. Sm. var. puralbum (Balf. f. & W. W. Sm.) D. F. Chamb. | | a | i |
| Rhododendron wardii W. W. Sm. var. wardii | | a | i |
| Rhododendron wasonii Hemsl. & E. H. Wilson | | a | |
| Rhododendron wellesleyanum Waterer ex Rehder | | a | |
| Rhododendron wightii Hook. f. | | a | i |
| Rhododendron williamsianum Rehder & E. H. Wilson | | a | |
| Rhododendron yakushimanum Nakai | Rhododendron degronianum Carriere subsp. yakushimanum (Nakai) H. Hara var. yakushimanum (Nakai) Kitam. | | |
| Rhododendron yakushimanum Nakai subsp. makinoi (Tagg ex Nakai) D. F. Chamb. | Rhododendron makinoi Tagg ex Nakai | | i |
| Rhododendron zeylanicum T. J. Booth | Rhododendron arboreum Sm. subsp. zeylanicum (T. J. Booth) Tagg | | |