| Rhododendron hybr. | | a | |
| Rhododendron spp. | | a | |
| Rhododendron aberconwayi Cowan | | a | |
| Rhododendron achroanthum Balf. f. & W. W. Sm. | Rhododendron rupicola W. W. Sm. var. rupicola | | i |
| Rhododendron acraium Balf. f. & W. W. Sm. | Rhododendron primuliflorum Bureau & Franch. | | i |
| Rhododendron acuminatum Hook. f. | | a | i |
| Rhododendron adamsii Rehder | | 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 albiflorum Hook. | | a | |
| Rhododendron albrechtii Maxim. | | 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 amagianum (Makino) H. Hara | | a | |
| Rhododendron amamiense Ohwi | Rhododendron latoucheae Franch. | | |
| Rhododendron amaurophyllum Balf. f. & Forrest | Rhododendron saluenense Franch. subsp. saluenense | | i |
| Rhododendron ambiguum Hemsl. | | a | |
| Rhododendron anagalliflorum Wernham | | a | |
| Rhododendron annae Franch. | | a | |
| Rhododendron anthopogon D. Don | | a | |
| Rhododendron anthopogon D. Don subsp. anthopogon | | a | i |
| Rhododendron anthopogon D. Don subsp. hypenanthum (Balf. f.) Cullen | | a | i |
| 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 arendsii Arends | | a | |
| 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 artosquameum Balf. f. & Forrest | Rhododendron oreotrephes W. W. Sm. | | i |
| Rhododendron atlanticum (Ashe) Rehder | | a | |
| Rhododendron atropurpureum Sleumer | | a | |
| Rhododendron aucklandii Hook. f. | Rhododendron griffithianum Wight | | i |
| Rhododendron augustinii Hemsl. | | a | |
| Rhododendron augustinii Hemsl. subsp. augustinii | | a | i |
| Rhododendron augustinii Hemsl. subsp. chasmanthum (Diels) Cullen | | a | i |
| Rhododendron augustinii Hemsl. subsp. hardyi (Davidian) Cullen | | a | i |
| Rhododendron augustinii Hemsl. subsp. rubrum (Davidian) Cullen | | a | i |
| Rhododendron aureum Georgi | | a | |
| Rhododendron auriculatum Hemsl. | | a | |
| Rhododendron aurigeranum Sleumer | | a | |
| Rhododendron auritum Tagg | | a | |
| Rhododendron austrinum (Small) Rehder | | a | |
| Rhododendron austrokiusianum Hatus. | Rhododendron obtusum (Lindl.) Planch. | | |
| Rhododendron azaleodendron M. Vilm. & Bois | | a | |
| Rhododendron azaleoides hort. ex Dum. Cours. | Rhododendron ponticum L. | | |
| Rhododendron baileyi Balf. f. | | a | i |
| Rhododendron bainbridgeanum Tagg & Forrest | | a | |
| Rhododendron balfourianum Diels | | a | |
| Rhododendron balfourianum Diels var. aganniphoides Tagg & Forrest | Rhododendron balfourianum Diels | | i |
| Rhododendron balsaminiflorum Carriere | Rhododendron indicum (L.) Sweet | | |
| 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 benhallii Craven | | a | |
| Rhododendron beyerinckianum Koord. | | a | |
| Rhododendron boothii Nutt. | | a | |
| Rhododendron brachyandrum Balf. f. & Forrest | Rhododendron eclecteum Balf. f. & Forrest var. eclecteum | | i |
| Rhododendron brachyanthum Franch. | | a | |
| Rhododendron brachyanthum Franch. subsp. brachyanthum | | a | i |
| Rhododendron brachyanthum Franch. subsp. hypolepidotum (Franch.) Cullen | | a | i |
| Rhododendron brachyanthum Franch. var. hypolepidotum Franch. | Rhododendron brachyanthum Franch. subsp. hypolepidotum (Franch.) Cullen | | 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 brevistylum Franch. | Rhododendron heliolepis Franch. var. brevistylum (Franch.) Cullen | | |
| Rhododendron brookeanum H. Low ex Lindl. | | a | |
| Rhododendron brunneifolium Balf. f. & Forrest | Rhododendron eudoxum Balf. f. & Forrest var. brunneifolium (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron bullatum Franch. | Rhododendron edgeworthii Hook. f. | | |
| Rhododendron bureavii Franch. | | a | |
| Rhododendron burmanicum Hutch. | | a | |
| Rhododendron buxifolium H. Low ex Hook. f. var. robustum Sleumer | | a | i |
| Rhododendron caeruleum H. Lev. | Rhododendron rigidum Franch. | | |
| Rhododendron calciphilum Hutch. & Kingdon-Ward | Rhododendron calostrotum Balf. f. & Kingdon-Ward subsp. riparium (Kingdon-Ward ex Hutch.) Cullen | | |
| 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 calostrotum Balf. f. & Kingdon-Ward | | a | i |
| Rhododendron calostrotum Balf. f. & Kingdon-Ward subsp. calostrotum | | a | i |
| Rhododendron calostrotum Balf. f. & Kingdon-Ward subsp. keleticum (Balf. f. & Forrest) Cullen | | a | i |
| Rhododendron calostrotum Balf. f. & Kingdon-Ward subsp. riparioides Cullen | | a | i |
| Rhododendron calostrotum Balf. f. & Kingdon-Ward subsp. riparium (Kingdon-Ward ex Hutch.) Cullen | | a | i |
| Rhododendron caloxanthum Balf. f. & Farrer | Rhododendron campylocarpum Hook. f. subsp. caloxanthum (Balf. f. & Farrer) D. F. Chamb. | | i |
| Rhododendron camelliiflorum Hook. f. | | a | 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 campylogynum Franch. | | a | |
| Rhododendron camtschaticum Pall. | Therorhodion camtschaticum (Pall.) Small | | |
| Rhododendron camtschaticum subsp. glandulosum | | 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 cantabile Balf. f. ex Hutch. | Rhododendron russatum Balf. f. & Forrest | | i |
| Rhododendron capitatum Maxim. | | a | |
| Rhododendron carneum Hutch. | | a | |
| Rhododendron carolinianum Rehder | Rhododendron minus Michx. var. minus | | |
| Rhododendron carringtoniae F. Muell. | | a | |
| Rhododendron catacosmum Balf. f. ex Tagg | | a | i |
| Rhododendron catawbiense Michx. | | a | |
| Rhododendron caucasicum Pall. | | a | |
| Rhododendron cephalanthum Franch. | | a | |
| Rhododendron cephalanthum Franch. subsp. cephalanthum | | a | i |
| Rhododendron cephalanthum Franch. subsp. platyphyllum (Balf. f. & W. W. Sm.) Cullen | | a | i |
| 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 chamaecistus L. | Rhodothamnus chamaecistus (L.) Rchb. | | |
| 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 chamaetortum Balf. f. & Kingdon-Ward | Rhododendron cephalanthum Franch. subsp. cephalanthum | | i |
| Rhododendron chamberlainii Craven | Diplarche multiflora Hook. f. & Thomson | | |
| Rhododendron chameunum Balf. f. & Forrest | Rhododendron saluenense Franch. subsp. chameunum (Balf. f. & Forrest) Cullen | | i |
| Rhododendron chapmanii (Alph. Wood) A. Gray | Rhododendron minus Michx. var. chapmanii (Alph. Wood) W. H. Duncan & Pullen | | |
| Rhododendron charitopes Balf. f. & Farrer | | a | i |
| Rhododendron charitostreptum Balf. f. & Kingdon-Ward | Rhododendron brachyanthum Franch. subsp. hypolepidotum (Franch.) Cullen | | i |
| Rhododendron chartophyllum Franch. | Rhododendron yunnanense Franch. | | |
| Rhododendron chasmanthoides Balf. f. & Forrest | Rhododendron augustinii Hemsl. subsp. chasmanthum (Diels) Cullen | | i |
| Rhododendron chasmanthum Diels | Rhododendron augustinii Hemsl. subsp. chasmanthum (Diels) Cullen | | |
| Rhododendron christianae Sleumer | | a | |
| Rhododendron christii F. Forst. | | a | |
| Rhododendron chrysanthum Pall. | Rhododendron aureum Georgi | | |
| Rhododendron chrysanthum Pall. var. nikomontanum Komatsu | Rhododendron nikomontanum (Komatsu) Nakai | | i |
| Rhododendron chryseum Balf. f. & Kingdon-Ward | Rhododendron rupicola W. W. Sm. var. chryseum (Balf. f. & Kingdon-Ward) Philipson & M. N. Philipson | | i |
| Rhododendron chrysodoron Tagg ex Hutch. | | a | |
| Rhododendron chrysolepis Hutch. & Kingdon-Ward | | a | |
| Rhododendron ciliatum Hook. f. | | a | i |
| Rhododendron ciliicalyx Franch. | | a | |
| Rhododendron cinnabarinum Hook. f. | | a | i |
| Rhododendron cinnabarinum Hook. f. subsp. cinnabarinum | | a | i |
| Rhododendron cinnabarinum Hook. f. subsp. tamaense (Davidian) Cullen | | a | i |
| Rhododendron cinnabarinum Hook. f. subsp. xanthocodon (Hutch.) Cullen | | a | 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 citrinum (Hassk.) Hassk. | | a | |
| Rhododendron clementinae Forrest | | a | |
| Rhododendron clivicola Balf. f. & W. W. Sm. | Rhododendron primuliflorum Bureau & Franch. | | i |
| 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 columbianum (Piper) Harmaja | | a | |
| Rhododendron commonae F. Forst. | | a | |
| Rhododendron concatenans Hutch. | Rhododendron cinnabarinum Hook. f. subsp. xanthocodon (Hutch.) Cullen | | |
| Rhododendron concinnum Hemsl. | | a | |
| Rhododendron coriaceum Franch. | | a | |
| Rhododendron coriifolium Sleumer | | a | |
| Rhododendron coryanum Tagg & Forrest | | a | |
| Rhododendron coryphaeum Balf. f. & Forrest | Rhododendron praestans Balf. f. & W. W. Sm. | | i |
| Rhododendron cosmetum Balf. f. & Forrest | Rhododendron saluenense Franch. subsp. chameunum (Balf. f. & Forrest) Cullen | | i |
| Rhododendron crassum Franch. | Rhododendron maddenii Hook. f. subsp. crassum (Franch.) Cullen | | |
| Rhododendron crebreflorum Hutch. & Kingdon-Ward | Rhododendron cephalanthum Franch. subsp. cephalanthum | | |
| Rhododendron crinigerum Franch. | | a | |
| Rhododendron croceum Balf. f. & W. W. Sm. | Rhododendron wardii W. W. Sm. var. wardii | | i |
| Rhododendron cruttwellii Sleumer | | a | |
| Rhododendron cubittii Hutch. | Rhododendron veitchianum Hook. | | |
| Rhododendron cucullatum Hand.-Mazz. | Rhododendron roxieanum Forrest var. cucullatum (Hand.-Mazz.) D. F. Chamb. | | |
| Rhododendron cuffeanum Craib ex Hutch. | | a | |
| Rhododendron culminicola F. Muell. | | a | |
| Rhododendron cumberlandense E. L. Braun | | a | |
| Rhododendron cuneatum W. W. Sm. | | a | |
| Rhododendron dalhousieae Hook. f. | | a | i |
| Rhododendron dalhousieae Hook. f. var. dalhousieae | | a | i |
| Rhododendron dalhousieae Hook. f. var. rhabdotum (Balf. f. & R. E. Cooper) Cullen | | a | i |
| Rhododendron dasycladum Balf. f. & W. W. Sm. | Rhododendron selense Franch. subsp. dasycladum (Balf. f. & W. W. Sm.) D. F. Chamb. | | i |
| Rhododendron dasypetalum Balf. f. & Forrest | | a | i |
| Rhododendron dauricum L. | | a | |
| Rhododendron dauricum L. var. mucronulatum (Turcz.) Maxim. | Rhododendron mucronulatum Turcz. var. mucronulatum | | i |
| Rhododendron dauricum L. var. sempervirens Sims | Rhododendron ledebourii Pojark. | | i |
| Rhododendron davidsonianum Rehder & E. H. Wilson | | a | |
| Rhododendron decandrum (Makino) Makino | | a | |
| 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 deleiense Hutch. & Kingdon-Ward | Rhododendron tephropeplum Balf. f. & Forrest | | |
| Rhododendron dendricola Hutch. | | a | |
| Rhododendron desquamatum Balf. f. & Forrest | Rhododendron rubiginosum Franch. | | i |
| 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 dielsianum Schltr. | | a | |
| Rhododendron dilatatum Miq. | | a | |
| Rhododendron dilatatum Miq. var. decandrum Makino | Rhododendron decandrum (Makino) Makino | | i |
| Rhododendron discolor Franch. | Rhododendron fortunei Lindl. subsp. discolor (Franch.) D. F. Chamb. | | |
| Rhododendron diversipilosum (Nakai) Harmaja | | a | |
| Rhododendron drumonium Balf. f. & Kingdon-Ward | Rhododendron telmateium Balf. f. & W. W. Sm. | | i |
| 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 edgarianum Rehder & E. H. Wilson | | a | |
| Rhododendron edgeworthii Hook. f. | | a | i |
| Rhododendron elliottii G. Watt | | a | |
| Rhododendron ellipticum Maxim. | Rhododendron moulmainense Hook. f. | | |
| Rhododendron erastum Balf. f. & Forrest | | a | i |
| Rhododendron ericoides H. Low ex Hook. f. | | a | i |
| Rhododendron eriocarpum (Hayata) Nakai | | a | |
| 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 exquisitum Hutch. | Rhododendron oreotrephes W. W. Sm. | | |
| 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 fallacinum Sleumer | | a | |
| Rhododendron fargesii Franch. | Rhododendron oreodoxa Franch. var. fargesii (Franch.) D. F. Chamb. | | |
| Rhododendron farrerae Tate ex Sweet | | a | |
| Rhododendron fastigiatum Franch. | | a | |
| Rhododendron fauriei Franch. | Rhododendron brachycarpum D. Don ex G. Don | | |
| Rhododendron ferrugineum L. | | a | |
| 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 formosum Wall. | | a | |
| Rhododendron formosum Wall. var. formosum | | a | i |
| Rhododendron formosum Wall. var. inaequale C. B. Clarke | | a | i |
| Rhododendron formosum Wall. var. johnstoneanum Brandis | Rhododendron johnstoneanum (Brandis) G. Watt ex Hutch. | | i |
| 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 forsterianum hort. ex Rehder | | a | |
| Rhododendron fortunei Lindl. | | a | |
| Rhododendron fortunei Lindl. subsp. discolor (Franch.) D. F. Chamb. | | a | i |
| Rhododendron fortunei Lindl. subsp. fortunei | | a | i |
| Rhododendron fragrans Paxton | | a | |
| Rhododendron fragrantissimum Burb. ex Rehder | | a | |
| 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 gaultheriifolium J. J. Sm. | | a | |
| Rhododendron genestierianum Forrest | | a | |
| Rhododendron giganteum Tagg | Rhododendron protistum Balf. f. & Forrest var. giganteum (Tagg) D. F. Chamb. | | |
| Rhododendron glaucophyllum Rehder | | a | |
| 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 glomerulatum Hutch. | Rhododendron yungningense Balf. f. ex Hutch. | | |
| Rhododendron gowenianum Sweet | Rhododendron hybr. | | |
| Rhododendron gracilentum F. Muell. | | a | |
| Rhododendron grande Wight | | a | |
| Rhododendron griersonianum Balf. f. & Forrest | | a | i |
| Rhododendron griffithianum Wight | | a | |
| Rhododendron groenlandicum (Oeder) Kron & Judd | | 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 hansemannii Warb. | Rhododendron macgregoriae F. Muell. | | |
| Rhododendron hardingii Forrest ex Tagg | Rhododendron annae Franch. | | |
| Rhododendron hardyi Davidian | Rhododendron augustinii Hemsl. subsp. hardyi (Davidian) Cullen | | |
| Rhododendron heliolepis Franch. | | a | |
| Rhododendron heliolepis Franch. var. brevistylum (Franch.) Cullen | | a | i |
| Rhododendron heliolepis Franch. var. heliolepis | | a | i |
| Rhododendron hemidartum Balf. f. ex Tagg | Rhododendron pocophorum Balf. f. ex Tagg var. hemidartum (Balf. f. ex Tagg) D. F. Chamb. | | i |
| Rhododendron hemitrichotum Balf. f. & Forrest | | a | i |
| Rhododendron heptamerum Balf. f. | Rhododendron anthosphaerum Diels | | i |
| Rhododendron herzogii Warb. | | a | |
| Rhododendron himertum Balf. f. & Forrest | Rhododendron sanguineum Franch. var. himertum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron hippophaeoides Balf. f. & W. W. Sm. | | a | i |
| Rhododendron hirsutum L. | | a | |
| 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 hypenanthum Balf. f. | Rhododendron anthopogon D. Don subsp. hypenanthum (Balf. f.) Cullen | | i |
| Rhododendron hyperythrum Hayata | | a | |
| Rhododendron hypoglaucum Hemsl. | Rhododendron argyrophyllum Franch. subsp. hypoglaucum (Hemsl.) D. F. Chamb. | | |
| Rhododendron hypolepidotum (Franch.) Balf. f. & Forrest | Rhododendron brachyanthum Franch. subsp. hypolepidotum (Franch.) Cullen | | i |
| Rhododendron hypoleucum (Kom.) Harmaja | | a | |
| Rhododendron impeditum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron imperator Kingdon-Ward | Rhododendron uniflorum Kingdon-Ward var. imperator (Kingdon-Ward) Cullen | | |
| Rhododendron inaequale (C. B. Clarke) Hutch. | Rhododendron formosum Wall. var. inaequale C. B. Clarke | | |
| Rhododendron inconspicuum J. J. Sm. | | a | |
| Rhododendron indicum (L.) Sweet | | a | |
| Rhododendron indicum (L.) Sweet f. japonicum Maxim. | Rhododendron kiusianum Makino | | i |
| Rhododendron indicum (L.) Sweet var. eriocarpum Hayata | Rhododendron eriocarpum (Hayata) Nakai | | i |
| Rhododendron indicum (L.) Sweet var. phoeniceum Sweet | Rhododendron pulchrum Sweet | | i |
| Rhododendron insculptum Hutch. & Kingdon-Ward | | a | |
| Rhododendron insigne Hemsl. & E. H. Wilson | | a | |
| Rhododendron intricatum Franch. | | a | |
| Rhododendron invasorium Sleumer | Rhododendron inconspicuum J. J. Sm. | | |
| 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 iteaphyllum Hutch. | Rhododendron formosum Wall. var. formosum | | |
| 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 jasminiflorum Hook. | | a | |
| Rhododendron jasminiflorum Hook. var. jasminiflorum | | a | i |
| Rhododendron jasminiflorum Hook. var. punctatum Ridl. | | a | i |
| Rhododendron javanicum (Blume) Benn. | | a | |
| Rhododendron javanicum (Blume) Benn. var. schadenbergii (Warb.) Sleumer | | a | i |
| Rhododendron jenestierianum Forrest | | a | |
| Rhododendron johnstoneanum (Brandis) G. Watt ex Hutch. | | a | |
| Rhododendron jucundum Balf. f. & W. W. Sm. | Rhododendron selense Franch. subsp. jucundum (Balf. f. & W. W. Sm.) D. F. Chamb. | | i |
| Rhododendron kaempferi Planch. | | a | |
| Rhododendron kaempferi Planch. f. album Nakai | Rhododendron kaempferi Planch. | | i |
| Rhododendron kamtschaticum Pall., orth. var. | Therorhodion camtschaticum (Pall.) Small | | i |
| Rhododendron kanehirae E. H. Wilson | | a | |
| Rhododendron kasoense Hutch. & Kingdon-Ward | | a | |
| Rhododendron kawakamii Hayata | | a | |
| Rhododendron keiskei Miq. | | a | |
| Rhododendron keleticum Balf. f. & Forrest | Rhododendron calostrotum Balf. f. & Kingdon-Ward subsp. keleticum (Balf. f. & Forrest) Cullen | | i |
| Rhododendron keysii Nutt. | | a | |
| Rhododendron kiusianum Makino | | a | |
| Rhododendron kiyosumense (Makino) Makino | | a | |
| Rhododendron komiyamae Makino | | a | |
| Rhododendron konori Becc. | | a | |
| Rhododendron kosterianum C. K. Schneid. | | a | |
| Rhododendron kroniae Craven | | a | |
| Rhododendron kyawi Lace & W. W. Sm. | | a | |
| Rhododendron lacteum Franch. | | a | |
| Rhododendron laetum J. J. Sm. | | a | |
| Rhododendron lanatum Hook. f. | | a | i |
| Rhododendron lanigerum Tagg | | a | |
| Rhododendron lapponicum (L.) Wahlenb. | | a | |
| Rhododendron lasiostylum Hayata | | a | |
| Rhododendron latoucheae Franch. | | a | |
| Rhododendron ledebourii Pojark. | | a | |
| Rhododendron lepidostylum Balf. f. & Forrest | | a | i |
| Rhododendron lepidotum Wall. ex G. Don | | a | |
| Rhododendron leptanthum F. Muell. | | a | |
| Rhododendron leptocarpum Nutt. | | a | |
| Rhododendron leptothrium Balf. f. & Forrest | | a | i |
| Rhododendron leucaspis Tagg | | a | |
| Rhododendron levistratum Balf. f. & Forrest | Rhododendron phaeochrysum Balf. f. & W. W. Sm. var. levistratum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron lindaueanum Koord. | | a | |
| Rhododendron lindleyi T. Moore | | a | |
| Rhododendron linearifolium Siebold & Zucc. | Rhododendron macrosepalum Maxim. | | |
| Rhododendron linearifolium Siebold & Zucc. var. macrosepalum (Maxim.) Makino | Rhododendron macrosepalum Maxim. | | i |
| Rhododendron litangense Balf. f. ex Hutch. | Rhododendron impeditum Balf. f. & W. W. Sm. | | i |
| Rhododendron litiense Balf. f. & Forrest | Rhododendron wardii W. W. Sm. var. wardii | | i |
| Rhododendron lochiae F. Muell. | | a | |
| Rhododendron loderi Millais | | a | |
| Rhododendron longiflorum Lindl. | | a | |
| Rhododendron longistylum Rehder & E. H. Wilson | | a | |
| Rhododendron lowii Hook. f. | | a | i |
| Rhododendron lowndesii Davidian | | a | |
| Rhododendron lucidum Franch. | Rhododendron vernicosum Franch. | | |
| Rhododendron ludlowii Cowan | | a | |
| Rhododendron lukiangense Franch. | | a | |
| Rhododendron luteosquamatum Sleumer | | a | |
| Rhododendron lutescens Franch. | | a | |
| Rhododendron luteum Sweet | | a | |
| Rhododendron lysolepis Hutch. | | a | |
| Rhododendron macabeanum G. Watt ex Balf. f. | | a | i |
| Rhododendron macgregoriae F. Muell. | | a | |
| Rhododendron macrocarpum Van Houtte | | a | |
| Rhododendron macrophyllum D. Don ex G. Don | | a | |
| Rhododendron macrosepalum Maxim. | | a | |
| Rhododendron macrostemon Maxim. | Rhododendron hybr. | | |
| Rhododendron maddenii Hook. f. | | a | i |
| Rhododendron maddenii Hook. f. subsp. crassum (Franch.) Cullen | | a | i |
| Rhododendron maddenii Hook. f. subsp. maddenii | | a | i |
| Rhododendron magnificum Kingdon-Ward | | a | |
| Rhododendron makinoi Tagg ex Nakai | | a | |
| Rhododendron manipurense Balf. f. & G. Watt | Rhododendron maddenii Hook. f. subsp. crassum (Franch.) Cullen | | i |
| Rhododendron mariesii Hemsl. & E. H. Wilson | | a | |
| Rhododendron martinianum Balf. f. & Forrest | | a | i |
| Rhododendron maximum L. | | a | |
| Rhododendron maxwellii Gibbs | | a | |
| Rhododendron maxwellii Millais | Rhododendron pulchrum Sweet | | |
| Rhododendron mayebarae Nakai & H. Hara | | a | |
| Rhododendron megacalyx Balf. f. & Kingdon-Ward | | a | i |
| Rhododendron megeratum Balf. f. & Forrest | | a | i |
| Rhododendron menziesii Craven | | a | |
| Rhododendron menziesii Craven subsp. glabella (A. Gray) Craven | | a | i |
| Rhododendron menziesii Craven subsp. menziesii | | a | i |
| 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 micranthum Turcz. | | a | |
| Rhododendron micromeres Tagg | Rhododendron leptocarpum Nutt. | | |
| Rhododendron microphyton Franch. | | a | |
| Rhododendron mimetes Tagg & Forrest | | a | |
| Rhododendron mimetes Tagg & Forrest var. simulans Tagg & Forrest | | a | i |
| Rhododendron minus Michx. | | a | |
| Rhododendron minus Michx. var. chapmanii (Alph. Wood) W. H. Duncan & Pullen | | a | i |
| Rhododendron minus Michx. var. minus | | a | i |
| Rhododendron mishmiense Hutch. & Kingdon-Ward | Rhododendron boothii Nutt. | | |
| 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 mollicomum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron morii Hayata | | a | |
| Rhododendron moulmainense Hook. f. | | a | i |
| Rhododendron moupinense Franch. | | a | |
| Rhododendron mucronatum (Blume) G. Don | | a | |
| Rhododendron mucronatum (Blume) G. Don var. mucronatum | | a | i |
| Rhododendron mucronatum (Blume) G. Don var. ripense (Makino) E. H. Wilson | | a | i |
| Rhododendron mucronulatum Turcz. | | a | |
| Rhododendron mucronulatum Turcz. var. ciliatum Nakai | | a | i |
| Rhododendron mucronulatum Turcz. var. maritimum Nakai | | a | i |
| Rhododendron mucronulatum Turcz. var. mucronulatum | | a | i |
| Rhododendron muliense Balf. f. & Forrest | Rhododendron rupicola W. W. Sm. var. muliense (Balf. f. & Forrest) Philipson & M. N. Philipson | | i |
| Rhododendron multicolor Miq. | | a | |
| Rhododendron multiflorum (Maxim.) Craven | | a | |
| Rhododendron multiflorum (Maxim.) Craven f. bicolor (Makino) Craven | | a | i |
| Rhododendron multiflorum (Maxim.) Craven var. purpurea (Makino) Craven | | a | i |
| Rhododendron multinervium Sleumer | | a | |
| Rhododendron myiagrum Balf. f. & Forrest | Rhododendron callimorphum Balf. f. & W. W. Sm. var. myiagrum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron myrtilloides Balf. f. & Kingdon-Ward | Rhododendron campylogynum Franch. | | i |
| Rhododendron nakaharae Hayata | | a | |
| Rhododendron neoglandulosum Harmaja | Rhododendron columbianum (Piper) Harmaja | | |
| 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 nipponicum Matsum. | | a | |
| Rhododendron nivale Hook. f. | | a | i |
| Rhododendron nivale Hook. f. subsp. australe Philipson & M. N. Philipson | | a | i |
| Rhododendron nivale Hook. f. subsp. boreale Philipson & M. N. Philipson | | a | i |
| Rhododendron nivale Hook. f. subsp. nivale | | a | 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 nudipes Nakai | | a | |
| Rhododendron nummatum J. J. Sm. | | a | |
| Rhododendron nuttallii T. J. Booth ex Nutt. | | a | |
| Rhododendron oblongifolium (Small) Millais | Rhododendron viscosum (L.) Torr. | | |
| Rhododendron obtusum (Lindl.) Planch. | | a | |
| Rhododendron obtusum (Lindl.) Planch. f. amoenum (Lindl.) E. H. Wilson | Rhododendron obtusum (Lindl.) Planch. | | i |
| Rhododendron obtusum (Lindl.) Planch. var. japonicum (Maxim.) Kitam. | Rhododendron kiusianum Makino | | i |
| Rhododendron obtusum (Lindl.) Planch. var. kaempferi (Planch.) E. H. Wilson | Rhododendron kaempferi Planch. | | i |
| Rhododendron occidentale (Torr. & A. Gray) A. Gray | | a | |
| Rhododendron oldhamii Maxim. | | a | |
| Rhododendron oleifolium Franch. | Rhododendron virgatum Hook. f. subsp. oleifolium (Franch.) Cullen | | |
| Rhododendron omurasaki Makino | Rhododendron pulchrum Sweet | | |
| 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 oreotrephes W. W. Sm. | | a | |
| Rhododendron oulotrichum Balf. f. & Forrest | Rhododendron trichocladum Franch. | | i |
| Rhododendron ovatum (Lindl.) Maxim. | | a | |
| Rhododendron pachypodum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron pagophilum Balf. f. & Kingdon-Ward | Rhododendron selense Franch. subsp. selense | | i |
| Rhododendron paludosum Hutch. & Kingdon-Ward | Rhododendron nivale Hook. f. subsp. nivale | | |
| Rhododendron palustre (L.) Kron & Judd | Rhododendron tomentosum Harmaja | | |
| Rhododendron parvifolium Adams | Rhododendron lapponicum (L.) Wahlenb. | | |
| Rhododendron pemakoense Kingdon-Ward | | a | |
| Rhododendron pentandrum (Maxim.) Craven | | a | |
| Rhododendron pentaphyllum Maxim. | | a | |
| Rhododendron pentaphyllum Maxim. var. nikoense Komatsu | | a | i |
| Rhododendron periclymenoides (Michx.) Shinners | | a | |
| Rhododendron phaedropum Balf. f. & Farrer | Rhododendron neriiflorum Franch. subsp. phaedropum (Balf. f. & Farrer) Tagg | | i |
| Rhododendron phaeochitum F. Muell. | | a | |
| 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 phoeniceum (Sweet) G. Don | Rhododendron pulchrum Sweet | | |
| Rhododendron phoeniceum (Sweet) G. Don var. calycinum (Lindl.) E. H. Wilson | Rhododendron pulchrum Sweet | | i |
| Rhododendron pilosum (Michx.) Craven | | a | |
| Rhododendron planetum Balf. f. | | a | i |
| Rhododendron platyphyllum Balf. f. & W. W. Sm. | Rhododendron cephalanthum Franch. subsp. platyphyllum (Balf. f. & W. W. Sm.) Cullen | | i |
| Rhododendron pleianthum Sleumer | | a | |
| 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 polycladum Franch. | | a | |
| Rhododendron ponticum L. | | a | |
| Rhododendron poukhanense H. Lev. | Rhododendron yedoense Maxim. var. poukhanense (H. Lev.) Nakai | | |
| Rhododendron praecox hort. | | a | |
| Rhododendron praestans Balf. f. & W. W. Sm. | | a | i |
| Rhododendron praevernum Hutch. | | a | |
| Rhododendron primuliflorum Bureau & Franch. | | a | |
| Rhododendron prinophyllum (Small) Millais | | a | |
| Rhododendron probum Balf. f. & Forrest | Rhododendron selense Franch. subsp. selense | | i |
| Rhododendron pronum Tagg & Forrest | | a | |
| Rhododendron prostratum W. W. Sm. | Rhododendron saluenense Franch. subsp. chameunum (Balf. f. & Forrest) Cullen | | |
| 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 pruniflorum Hutch. & Kingdon-Ward | | a | |
| Rhododendron prunifolium (Small) Millais | | a | |
| Rhododendron przewalskii Maxim. | | a | |
| Rhododendron pseudochrysanthum Hayata | | a | |
| Rhododendron pseudoyanthinum Balf. f. ex Hutch. | Rhododendron concinnum Hemsl. | | i |
| Rhododendron pubescens Balf. f. & Forrest | | a | i |
| Rhododendron pulchrum Sweet | | a | |
| Rhododendron pulchrum Sweet var. calycinum (Lindl.) Rehder | Rhododendron pulchrum Sweet | | i |
| Rhododendron pulchrum Sweet var. maxwellii Rehder | Rhododendron pulchrum Sweet | | i |
| Rhododendron pulchrum Sweet var. phoeniceum (Sweet) Rehder | Rhododendron pulchrum Sweet | | i |
| Rhododendron pulchrum Sweet var. tebotan (Komatsu) Rehder | Rhododendron hybr. | | i |
| Rhododendron pumilum Hook. f. | | a | i |
| Rhododendron punctatum Andrews | Rhododendron minus Michx. var. minus | | |
| Rhododendron punctatum Andrews var. chapmanii Alph. Wood | Rhododendron minus Michx. var. chapmanii (Alph. Wood) W. H. Duncan & Pullen | | i |
| 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 quinquefolium Bisset & S. Moore | | a | |
| Rhododendron racemosum Franch. | | a | i |
| Rhododendron radicans Balf. f. & Forrest | Rhododendron calostrotum Balf. f. & Kingdon-Ward subsp. keleticum (Balf. f. & Forrest) Cullen | | i |
| Rhododendron radinum Balf. f. & W. W. Sm. | Rhododendron trichostomum Franch. | | i |
| Rhododendron rarum Schltr. | | a | |
| Rhododendron ravum Balf. f. & W. W. Sm. | Rhododendron cuneatum W. W. Sm. | | i |
| 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 redowskianum Maxim. | Therorhodion redowskianum (Maxim.) Hutch. | | |
| 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 reticulatum D. Don ex G. Don | | a | |
| Rhododendron retusum (Blume) Benn. | | a | |
| 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 rhabdotum Balf. f. & R. E. Cooper | Rhododendron dalhousieae Hook. f. var. rhabdotum (Balf. f. & R. E. Cooper) Cullen | | i |
| Rhododendron rhaibocarpum Balf. f. & W. W. Sm. | Rhododendron selense Franch. subsp. dasycladum (Balf. f. & W. W. Sm.) D. F. Chamb. | | i |
| Rhododendron rhombicum Miq. | Rhododendron reticulatum D. Don ex G. Don | | |
| Rhododendron rigidum Franch. | | a | |
| Rhododendron riparium Kingdon-Ward ex Hutch. | Rhododendron calostrotum Balf. f. & Kingdon-Ward subsp. riparium (Kingdon-Ward ex Hutch.) Cullen | | |
| Rhododendron ripense Makino | Rhododendron mucronatum (Blume) G. Don var. ripense (Makino) E. H. Wilson | | |
| 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 roylei Hook. f. | Rhododendron cinnabarinum Hook. f. subsp. cinnabarinum | | i |
| Rhododendron rubiginosum Franch. | | a | |
| Rhododendron rubropilosum Hayata | | a | |
| Rhododendron rubrum Davidian | Rhododendron augustinii Hemsl. subsp. rubrum (Davidian) Cullen | | |
| Rhododendron rufescens Franch. | | a | |
| Rhododendron rufohirtum Hand.-Mazz. | | a | |
| Rhododendron rufum Batalin | | a | |
| Rhododendron rugosum H. Low ex Hook. f. | | a | i |
| Rhododendron rugosum H. Low ex Hook. f. var. coriifolium (Sleumer) Sleumer | Rhododendron coriifolium Sleumer | | i |
| Rhododendron rupicola W. W. Sm. | | a | |
| Rhododendron rupicola W. W. Sm. var. chryseum (Balf. f. & Kingdon-Ward) Philipson & M. N. Philipson | | a | i |
| Rhododendron rupicola W. W. Sm. var. muliense (Balf. f. & Forrest) Philipson & M. N. Philipson | | a | i |
| Rhododendron rupicola W. W. Sm. var. rupicola | | a | i |
| Rhododendron russatum Balf. f. & Forrest | | a | i |
| Rhododendron russotinctum Balf. f. & Forrest | Rhododendron alutaceum Balf. f. & W. W. Sm. var. russotinctum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron saluenense Franch. | | a | |
| Rhododendron saluenense Franch. subsp. chameunum (Balf. f. & Forrest) Cullen | | a | i |
| Rhododendron saluenense Franch. subsp. saluenense | | a | i |
| Rhododendron sanctum Nakai | | a | |
| 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 sargentianum Rehder & E. H. Wilson | | a | |
| Rhododendron sataense Nakai | Rhododendron obtusum (Lindl.) Planch. | | |
| Rhododendron scabridibracteum Sleumer | | a | |
| Rhododendron scabrum G. Don | | a | |
| Rhododendron schadenbergii Warb. | Rhododendron javanicum (Blume) Benn. var. schadenbergii (Warb.) Sleumer | | |
| Rhododendron schizopeplum Balf. f. & Forrest | Rhododendron aganniphum Balf. f. & Kingdon-Ward var. aganniphum | | i |
| Rhododendron schlippenbachii Maxim. | | a | |
| Rhododendron scintillans Balf. f. & W. W. Sm. | Rhododendron polycladum Franch. | | i |
| Rhododendron scyphocalyx Balf. f. & Forrest | Rhododendron dichroanthum Diels subsp. scyphocalyx (Balf. f. & Forrest) Cowan | | i |
| Rhododendron searsiae Rehder & E. H. Wilson | | a | |
| Rhododendron seinghkuense Kingdon-Ward ex Hutch. | | a | |
| 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 semibarbatum Maxim. | | a | |
| Rhododendron serpens Balf. f. & Forrest | Rhododendron erastum Balf. f. & Forrest | | i |
| Rhododendron serpyllifolium (A. Gray) Miq. | | a | |
| Rhododendron setiferum Balf. f. & Forrest | Rhododendron selense Franch. subsp. setiferum (Balf. f. & Forrest) D. F. Chamb. | | i |
| Rhododendron setosum D. Don | | a | |
| Rhododendron shikokianum Makino, nom. inval. | Rhododendron weyrichii Maxim. | | |
| Rhododendron sichotense Pojark. | | a | |
| Rhododendron sidereum Balf. f. | | a | i |
| Rhododendron siderophyllum Franch. | | a | |
| 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 simsii Planch. | | 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 sinonuttallii Balf. f. & Forrest | Rhododendron nuttallii T. J. Booth ex Nutt. | | 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 spinuliferum Franch. | | a | |
| Rhododendron stenaulum Balf. f. & W. W. Sm. | Rhododendron moulmainense Hook. f. | | i |
| Rhododendron stewartianum Diels | | a | |
| Rhododendron strigillosum Franch. | | a | |
| Rhododendron subarcticum Harmaja | | a | |
| Rhododendron suberosum Balf. f. & Forrest | Rhododendron yunnanense Franch. | | i |
| Rhododendron sublanceolatum Miq. | Rhododendron scabrum G. Don | | |
| Rhododendron subsessile Rendle | | a | |
| Rhododendron subulatum (Nakai) Harmaja | | a | |
| Rhododendron superbum Sleumer | | a | |
| Rhododendron supranubium Hutch. | Rhododendron pachypodum Balf. f. & W. W. Sm. | | |
| Rhododendron sutchuenense Franch. | | a | |
| Rhododendron taggianum Hutch. | | a | |
| Rhododendron taliense Franch. | | a | |
| Rhododendron tamaense Davidian | Rhododendron cinnabarinum Hook. f. subsp. tamaense (Davidian) Cullen | | |
| Rhododendron tanakae (Maxim.) Ohwi | Rhododendron tsusiophyllum Sugim. | | |
| Rhododendron tanastylum Balf. f. & Kingdon-Ward | | a | i |
| Rhododendron tashiroi Maxim. | | a | |
| Rhododendron taylorii hort. Veitch | Rhododendron hybr. | | |
| Rhododendron tebotan Komatsu | Rhododendron hybr. | | |
| Rhododendron tectum Koidz. | | a | |
| Rhododendron telmateium Balf. f. & W. W. Sm. | | 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 tephropeplum Balf. f. & Forrest | | a | i |
| Rhododendron thomsonii Hook. f. | | a | i |
| Rhododendron timeteum Balf. f. & Forrest | Rhododendron oreotrephes W. W. Sm. | | i |
| Rhododendron tolmachevii Harmaja | | a | |
| Rhododendron tomentosum Harmaja | | a | |
| Rhododendron tomentosum Harmaja subsp. subarcticum (Harmaja) G. D. Wallace | Rhododendron subarcticum Harmaja | | i |
| Rhododendron tomentosum Harmaja subsp. tomentosum | Rhododendron tomentosum Harmaja | | i |
| Rhododendron tosaense Makino | | a | |
| 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 trichocladum Franch. | | a | |
| Rhododendron trichomiscum Balf. f. & Forrest | Rhododendron eudoxum Balf. f. & Forrest var. eudoxum | | i |
| Rhododendron trichostomum Franch. | | a | |
| Rhododendron triflorum Hook. f. | | a | 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 triumphans Yersin & A. Chev. | | a | |
| Rhododendron tschonoskii Maxim. | | a | |
| Rhododendron tsusiophyllum Sugim. | | a | |
| Rhododendron ungernii Trautv. | | a | |
| Rhododendron uniflorum Kingdon-Ward | | a | |
| Rhododendron uniflorum Kingdon-Ward var. imperator (Kingdon-Ward) Cullen | | a | i |
| Rhododendron uniflorum Kingdon-Ward var. uniflorum | | a | i |
| Rhododendron uvarifolium Diels | | a | |
| Rhododendron vaccinioides Hook. f. | | a | i |
| Rhododendron valentinianum Forrest ex Hutch. | | a | |
| Rhododendron vandeursenii Sleumer | Rhododendron vitis-idaea Sleumer | | |
| Rhododendron vaseyi A. Gray | | a | |
| Rhododendron veitchianum Hook. | | a | |
| Rhododendron vernicosum Franch. | | a | |
| Rhododendron vesiculiferum Tagg | | a | |
| Rhododendron vidalii Rolfe | | a | |
| Rhododendron vilmorinianum Balf. f. | Rhododendron augustinii Hemsl. subsp. augustinii | | i |
| Rhododendron virgatum Hook. f. | | a | i |
| Rhododendron virgatum Hook. f. subsp. oleifolium (Franch.) Cullen | | a | i |
| Rhododendron virgatum Hook. f. subsp. virgatum | | a | i |
| Rhododendron viscosepalum Rehder | Rhododendron hybr. | | |
| Rhododendron viscosepalum Rehder var. daviesii Rehder | Rhododendron hybr. | | i |
| 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 vitis-idaea Sleumer | | a | |
| Rhododendron wadanum Makino | | a | |
| 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 weyrichii Maxim. | | a | |
| Rhododendron wightii Hook. f. | | a | i |
| Rhododendron williamsianum Rehder & E. H. Wilson | | a | |
| Rhododendron womersleyi Sleumer | | a | |
| Rhododendron xanthocodon Hutch. | Rhododendron cinnabarinum Hook. f. subsp. xanthocodon (Hutch.) Cullen | | |
| 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 yanthinum Bureau & Franch. | Rhododendron concinnum Hemsl. | | |
| Rhododendron yedoense Maxim. | | a | |
| Rhododendron yedoense Maxim. var. poukhanense (H. Lev.) Nakai | | a | i |
| Rhododendron yedoense Maxim. var. yedoense | | a | i |
| Rhododendron yelliotii Warb. | | a | |
| Rhododendron yungningense Balf. f. ex Hutch. | | a | i |
| Rhododendron yunnanense Franch. | | a | |
| Rhododendron zaleucum Balf. f. & W. W. Sm. | | a | i |
| Rhododendron zeylanicum T. J. Booth | Rhododendron arboreum Sm. subsp. zeylanicum (T. J. Booth) Tagg | | |
| Rhododendron zoelleri Warb. | | a | |